Biomedical subjects

G W Trotter

Publications and source records attributed to G W Trotter.

At least 19 recordsLinked to original sources

PubMed2005

Effects of glucosamine hydrochloride and chondroitin sulphate, alone and in combination, on normal and interleukin-1 conditioned equine articular cartilage explant metabolism.

REASONS FOR PERFORMING STUDY: Clinical trials in human and veterinary literature have documented the benefits of oral nutraceutical joint supplements containing glucosamine (GU) and chondroitin sulphate (CS) to treat mild to moderate osteoarthritis, but the effects of these components have not yet been conclusively determined. OBJECTIVES: To assess varying dosages of GU and CS on normal and interleukin-1alpha (IL-1) conditioned equine cartilage explants and rationalise the use of these products. HYPOTHESIS: Treatment would not be detrimental to cartilage metabolism and higher dosages and the combination of GU and CS would be more beneficial than lower dosages and. GU or CS alone. METHODS: Articular cartilage explants collected from the femoral trochlea and condyles were cultured in normal and IL-1 conditioned media. Treatment groups included 0, 12.5, 25,125 and 250 microg/ml concentrations of GU alone, CS alone, or GU+CS in combination. Glycosaminoglycan (GAG) synthesis and total GAG content in the explants and media were analysed. RESULTS: There were no detrimental effects of GU, CS or GU+CS on cartilage metabolism. High dosages of GU+CS reduced total GAG release into the media (degradation). CONCLUSIONS: Our results suggests that GU+CS may prevent cartilage GAG degradation. POTENTIAL RELEVANCE: The combination of GU and CS may be more effective in preventing or treating osteoarthritis in horses than either product alone.

Animals↗

PubMed2003

Effects of dosage titration of methylprednisolone acetate and triamcinolone acetonide on interleukin-1-conditioned equine articular cartilage explants in vitro.

REASONS FOR PERFORMING STUDY: Osteoarthritis is a frequent sequela of joint disease, especially with severe injuries or if attempts at therapy are unsuccessful. Negative and positive effects of corticosteroid treatment of articular cartilage have been demonstrated by in vitro and in vivo studies. OBJECTIVES: To assess the metabolic effects of varying dosages of methylprednisolone acetate (MPA) and triamcinolone acetonide (TA) on interleukin-1alpha (IL-1) conditioned equine cartilage explants. Our hypothesis was that lower dosages of corticosteroids would be less detrimental to cartilage metabolism than higher dosages. TA would be less detrimental to cartilage metabolism than MPA. METHODS: Treatment groups included articular cartilage explants with no IL-1 (control), IL-1 alone, and IL-1 plus 10, 5, 1 and 0.5 mg/ml MPA or 1.2, 0.6, 0.12 and 0.06 mg/ml TA. Explants were labelled with 35SO4 prior to the beginning and end of the experiment to assess glycosaminoglycan (GAG) degradation and synthesis, respectively. Total GAG content in media and explants and total cartilage DNA were also analysed. RESULTS: MPA and TA reduced GAG synthesis compared to control and IL-1 alone. The highest dosage of MPA (10 mg/ml) reduced GAG synthesis less than lower dosages of MPA and all dosages of TA. Compared to IL-1 alone, all dosages of TA and lower dosages of MPA increased GAG degradation. MPA at 10 mg/ml reduced GAG degradation. Both MPA and TA increased media GAG content compared to control and IL-1 explants. Total cartilage GAGs were unchanged with MPA, but reduced with TA, compared with IL-1 alone. Total cartilage DNA was decreased with MPA and increased with TA compared to IL-1 and control explants. CONCLUSIONS: MPA and TA did not counteract the negative effects of IL-1 and did not maintain cartilage metabolism at control levels. Lower dosages of MPA and TA were not less detrimental to cartilage metabolism than higher dosages. TA did not appear to be less harmful than MPA on cartilage metabolism. The results of this study differ from the findings of comparable in vivo studies. POTENTIAL RELEVANCE: The low numbers of horses used in this study limits extrapolation of these findings to the equine population; however, this study also questions the clinical relevance of this in vitro model.

Animals↗

PubMed2001

Synovial fluid gelatinase concentrations and matrix metalloproteinase and cytokine expression in naturally occurring joint disease in horses.

OBJECTIVES: To determine concentrations of matrix metalloproteinase (MMP)-2 and -9 in synovial fluid; and mRNA expression of MMP-1, -13, and -3; interleukin[IL]-1alpha and beta; and tumor necrosis factor (TNF)-alpha in synovial membrane and articular cartilage from horses with naturally occurring joint disease. SAMPLE POPULATION: Synovial fluid (n = 76), synovial membrane (59), and articular cartilage (45) from 5 clinically normal horses and 55 horses with joint disease categorized as traumatic (acute [AT] or chronic [CT]), osteochondritis dissecans (OCD), or septic (S). PROCEDURE: Synovial fluid gelatinase concentrations were analyzed, using zymography. Synovial membrane and articular cartilage mRNA expression for MMP-1, -3, and -13, IL-1alpha and beta, TNF-alpha, type-II collagen, and aggrecan were analyzed, using quantitative reverse transcriptase-polymerase chain reaction. RESULTS: Synovial fluid pro-MMP-2 concentration was significantly higher in diseased joints than normal joints. Septic joints had significantly higher concentrations of pro and active MMP-9. Stromelysin-1 was expressed in > or = 80% of synovial membrane and articular cartilage samples and was strongly influenced by age. Collagenases were rarely expressed, with MMP-13 expressed only in diseased joints. Interleukin-1beta expression was significantly higher in all OCD samples and was influenced by age. Tumor necrosis factor-alpha expression was significantly higher in cartilage from joints with AT and OCD. There was no correlation between MMP or cytokines and type-II collagen or aggrecan expression. CONCLUSIONS AND CLINICAL RELEVANCE: Matrix metalloproteinase-2 and -3 are abundant in naturally occurring joint disease and normal joints. Interleukin-1beta and TNF-alpha may be important in the pathogenesis of OCD. Age affects MMP and IL-1beta concentrations.

Animals↗

PubMed2000

Removal of large fragments of the extensor process of the distal phalanx via arthrotomy in horses: 14 cases (1992-1998).

OBJECTIVE: To evaluate the outcome of horses with large fragments of the extensor process of the distal phalanx that were removed by use of arthrotomy. DESIGN: Retrospective study. ANIMALS: 14 horses with large fragments of the extensor process of the distal phalanx. PROCEDURE: Medical records for horses with large fragments of the extensor process that were removed by use of arthrotomy were reviewed. Data retrieved from medical records included signalment, use of horse, affected limb, lameness history, lameness examination findings, radiographic findings, surgical technique, and outcome. Follow-up evaluation was obtained by telephone interview. RESULTS: Most affected horses were < 5 years old and had a history of chronic lameness. Lameness grade ranged from 1/5 to 4/5. Fragments involved 20 to 45% of the dorsopalmar articular surface of the distal phalanx. Eight of 14 horses had a successful outcome. Outcome was not associated with age, duration or severity of lameness, or fragment size. CONCLUSIONS AND CLINICAL RELEVANCE: Despite involvement of a large portion of the articular surface and use of arthrotomy, joint instability and permanent soft tissue injury was not a problem in most horses. Outcome may be improved by selection of horses with lameness of < 2 years' duration and careful management after surgery. A fair prognosis may be anticipated for removal of large fragments of the extensor process via arthrotomy.

Animals↗

PubMed2000

Metabolic and mitogenic activities of insulin-like growth factor-1 in interleukin-1-conditioned equine cartilage.

OBJECTIVE: To determine response of interleukin-1alpha (IL-1alpha)-conditioned equine articular cartilage explants to insulin-like growth factor-1 (IGF-1). Sample Population-Cartilage from the trochlea and condyles of the femur of a clinically normal 4-year-old horse. PROCEDURE: Effects of IGF-1 (0 to 500 ng/ml) after addition of IL-1alpha were evaluated by assessing matrix responses, using a sulfated glycosaminoglycan (GAG) assay, matrix 35SO4 GAG incorporation, and release of GAG. Mitogenic response was assessed by 3H-thymidine incorporation into DNA and fluorometric assay of total DNA concentration. RESULTS: Human recombinant IL-1alpha (40 ng/ml) increased the amount of labeled GAG released and decreased labeled and total GAG remaining in explants, and IL-1alpha decreased mitogenic response. Addition of IGF-1 counteracted effects seen with IL-1alpha alone. In general, IGF-1 decreased total and labeled GAG released into the medium, compared with IL-1alpha-treated explants (positive-control sample). Values for these variables did not differ significantly from those for negative-control explants. A significant increase in total and newly synthesized GAG in the explants at termination of the experiment was observed with 500 ng of IGF-1/ml. Labeled GAG remaining in explants was greater with treatment at 50 ng of IGF-1/ml, compared with treatment with IL-1alpha alone. Concentrations of 200 ng of IGF-1/ml abolished actions of IL-1alpha and restored DNA synthesis to values similar to those of negative-control explants. CONCLUSIONS AND CLINICAL RELEVANCE: IGF-1 at 500 ng/ml was best at overcoming detrimental effects associated with IL-1alpha in in vitro explants. These beneficial effects may be useful in horses with osteoarthritis.

Animals↗

PubMed2000

Comparison of Northern blot hybridization and a reverse transcriptase-polymerase chain reaction technique for measurement of mRNA expression of metalloproteinases and matrix components in articular cartilage and synovial membrane from horses with osteoarthritis.

OBJECTIVE: To determine relative amounts of mRNA expression of aggrecan, type-II collagen, matrix metalloproteinase (MMP) 1, and MMP3 in articular cartilage and synovial membrane samples from healthy equine joints and joints with osteoarthritis (OA) and to compare results of Northern blot hybridization with results of a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. SAMPLE POPULATION: Articular cartilage samples from 8 pairs of joints (1 with OA and 1 healthy) from 6 horses and synovial membrane samples from 6 pairs of joints from 5 horses. PROCEDURE: RNA was extracted from samples by use of a modified Trizol procedure. Northern blot hybridization and the RT-PCR assay were performed; results were quantitated by use of glyceraldehyde 3-phosphate dehydrogenase as an internal standard. RESULTS: Articular cartilage samples from joints with mild or moderate OA yielded less total RNA than samples from joints with severe OA. Northern blot hybridization indicated that type-II collagen mRNA expression in articular cartilage samples from joints with OA was significantly greater than expression in samples from healthy joints. The RT-PCR assay identified low levels of MMP3 mRNA expression in 4 of 8 sets of articular cartilage samples and 4 of 6 sets of synovial membrane samples, whereas Northern blot hybridization identified MMP3 mRNA expression in only 1 of 6 sets of articular cartilage samples and 1 of 6 sets of synovial membrane samples. CONCLUSIONS: A RT-PCR assay is more sensitive than Northern blot hybridization for detection of MMP3 mRNA expression in articular cartilage and synovial membrane and requires smaller samples.

Aggrecans↗

PubMed1998

Arthroscopic removal of abaxial fracture fragments of the proximal sesamoid bones in horses: 47 cases (1989-1997).

OBJECTIVE: To determine the outcome of horses after arthroscopic removal of abaxial fracture fragments of the proximal sesamoid bone and association of fracture grade with outcome. DESIGN: Retrospective study. ANIMALS: 47 horses. PROCEDURE: Information obtained from dorsopalmar and dorsoplantar radiographic views of metacarpophalangeal and metatarsophalangeal joints was used to classify fractures as grade 1 (< 15 mm long), grade 2 (15 to 25 mm long), and grade 3 (> 25 mm long) and type 1 (abaxial) and type 2 (apical-abaxial). Outcome was determined by whether the horse returned to its intended use, raced in the same class or higher (racehorses), or performed satisfactorily (nonracehorses). Number of starts, performance index, and money earned were also used to evaluate performance of racehorses. RESULTS: Follow-up information was obtained for 41 horses (35 racehorses, 6 nonracehorses). Twenty-five racehorses were able to return to racing (16 in the same class, 9 in a lower class). All 6 nonracehorses were able to return to performance at the same level. Horses with small fracture fragments or fractures involving the abaxial aspect of the proximal sesamoid bone only had a more favorable outcome, compared with horses with large or apical-abaxial fractures. CLINICAL IMPLICATIONS: Overall, horses with abaxial fractures of the proximal sesamoid bone have a favorable prognosis for return to racing, but only a fair prognosis for return to racing in the same class, after arthroscopic removal of fracture fragments. Successful results can be expected for nonracehorses.

Age Factors↗

PubMed1998

The assessment of chondrocyte proteoglycan metabolism using molecular sieve column chromatography as compared to three commonly utilized techniques.

OBJECTIVE: Various methods have been used to quantify [35S] sulfate incorporation into proteoglycans and separate this from unincorporated [35S] sulfate. The methods currently used have not been compared for accuracy or precision, ease of completion and relative economics. This experiment evaluated and compared cetylpyridinium chloride (CPC) precipitation, potassium acetate (KAc) precipitation, rapid filtration, modified dye-binding (AB) technique to molecular weight exclusion chromatography (PD-10) as techniques to quantitate chondrocyte proteoglycan metabolism. METHODS: Each of the first three techniques was compared to the PD-10 technique as a 'gold standard' based on this technique's accuracy, precision and repeatability in molecular weight exclusion utilizing sieve chromatography. Articular cartilage was harvested, cultured and labeled with [35S] sulfate in a routine manner. Seventeen samples were processed and each was analyzed by the four different methodologies. Linear regression analysis was used to predict the linear relationship of PD-10 chromatography to the other methods (CPC, KAc, and AB) in the amount of proteoglycan synthesis in a pulse chase experiment. RESULTS: The KAc and AB methods had a significant linear relationship to the PD-10 method but the CPC did not. The AB technique was much easier than the KAc method to complete although the relative economics were similar per sample, when capital equipment costs were not considered. CONCLUSIONS: Either the KAc or AB methods compared favorably to the PD-10 method, although the AB procedure was much easier, and was more precise and more accurate. The CPC method did not compare favorably to the PD-10 method in precision or accuracy although it was easier and cost effective.

Alcian Blue↗

PubMed1998

Effects of osteochondral fragmentation and intra-articular triamcinolone acetonide treatment on subchondral bone in the equine carpus.

To determine the effects of osteochondral fragmentation and intra-articular corticosteroid treatment on dynamics of bone remodelling and fragility, 12 horses each had a unilateral, 8 mm osteochondral fragment created in the distal aspect of one radiocarpal bone. Six of the horses were treated in the fragmented joint, and the other 6 were treated in the nonfragmented joint with 12 mg of triamcinolone acetonide (TA) 14 and 28 days after surgery. All horses were exercised on a high-speed treadmill starting 15 days, and ending 72 days after surgery. Horses treated with TA in the fragmented joints were significantly less lame than those treated in the nonfragmented joints. Third carpal bones from joints with fragments showed significantly more vascularity, single labelled surface, total labelled surface and mineralising surface in subchondral and subjacent trabecular bone. Trends were also seen towards higher vascular canal volume and osteochondral junction remodelling sites in third carpal bones from fragmented joints. No significant differences were seen in microdamage density or size between fragmented and nonfragmented joints. No significant influence of TA treatment was seen on any parameter measured. The results from this study show that osteochondral fragmentation induces significant changes in remodelling of opposing bones, and that the administration of corticosteroids into joints with fragmentation does not significantly alter bone remodelling or fragility.

Animals↗

PubMed1998

CLoning of equine interleukin 1 alpha and equine interleukin 1 beta and determination of their full-length cDNA sequences.

OBJECTIVES: To clone equine interleukin 1 alpha (IL-1 alpha) and equine interleukin 1 beta (IL-1 beta) and determine their full-length cDNA sequences. PROCEDURES: The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a lambda phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1 alpha and IL-1 beta cDNA probes. The cDNA nucleotide sequences for equine IL-1 alpha and equine IL-1 beta were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using computer software, for sequence characteristics and compared with sequences reported for other species. RESULTS: The cDNA for equine IL-1 alpha was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equine IL-1 beta was 1,473 base pairs in length with an ORF encoding a peptide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL-1 alpha and sequences for IL-1 alpha of other species ranged from 62.5 to 82.2%; similarity between amino acid sequence of equine IL-1 beta and sequences for IL-1 beta of other species ranged from 62.5 to 82.2%; similarity between amino acid sequences of equine IL-1 alpha and equine IL-1 beta was 26%. CONCLUSIONS AND CLINICAL RELEVANCE: Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses.

Amino Acid Sequence↗

PubMed1998

Cloning of equine interleukin 1 receptor antagonist and determination of its full-length cDNA sequence.

OBJECTIVES: To clone equine interleukin 1 receptor antagonist (IL-1ra) and determine its full-length cDNA sequence. PROCEDURE: A cDNA library derived from lipopolysaccharide-stimulated equine monocytes was screened by means of plaque hybridization to radiolabeled equine IL-1ra DNA probes generated by means of the polymerase chain reaction. The cDNA nucleotide sequence for equine IL-1ra was determined by use of the dideoxy chain termination technique, analyzed by use of computer software for sequence characteristics, and compared with sequences reported for IL-1ra of other species. RESULTS: The cDNA of equine IL-1ra was 1,614 base pairs in length with an ORF encoding a peptide of 177 amino acids with a predicted molecular mass of 20.427 kd. Similarity between the amino acid sequence of equine IL-1ra and sequences for human, murine, rat, and lapine IL-1ra was 76%. Similarity between sequence for equine IL-1ra and sequences for equine interleukin-1 alpha and equine interleukin-1 beta were 22.6 and 24.6%, respectively. CONCLUSION: Comparison of the sequence for equine IL-1ra with sequences for IL-1ra of other species indicated a high degree of conservation. CLINICAL RELEVANCE: Results establish a basis for studying the roles of interleukin-1 in healthy and diseased joints in horses.

Amino Acid Sequence↗

PubMed1998

Effects of 6alpha-methylprednisolone acetate on an equine osteochondral fragment exercise model.

OBJECTIVE: To determine effects of intra-articularly administered 6alpha-methylprednisolone acetate (MPA) in exercised horses with carpal osteochondral fragmentation. ANIMALS: 18 horses: 3 groups of 6 each. PROCEDURE: An osteochondral (chip) fragment was created in 1 randomly chosen middle carpal joint of each horse. Polyionic fluid (PF) was injected into both middle carpal joints of horses in the control group. In horses of the MPA-control group, MPA was injected into the middle carpal joint without an osteochondral fragment; a similar volume of PF was injected into the contralateral middle carpal joint. In the MPA-treated group of horses, 100 mg of MPA was injected into the middle carpal joint containing the osteochondral fragment; a similar volume of PF was injected into the contralateral joint. Injections were administered on postsurgical days 14 and 28, and horses were exercised on a high-speed treadmill for 8 weeks, starting on postsurgical day 15. RESULTS: Clinical improvement in degree of lameness was not associated with MPA administration. Joints that contained an osteochondral fragment and were treated with MPA had lower prostaglandin E2 concentration in synovial fluid, and lower scores for intimal hyperplasia and vascularity in synovial membrane, compared with PF-treated joints. However, articular cartilage erosion and morphologic lesions suggested possible deleterious effect of intra-articular MPA administration. CONCLUSIONS: Some beneficial effects of MPA administration on synovial fluid and synovial membrane were identified; however, the deleterious findings contrast with those associated with triamcinolone acetonide used in a similar model, but agree with other results of MPA administration in normal and abnormal joints.

Animals↗

PubMed1997

Effects of triamcinolone acetonide on an in vivo equine osteochondral fragment exercise model.

The objective of this study was to determine the effects of intra-articularly administered triamcinolone acetonide (TA) in exercised equine athletes with carpal osteochondral fragmentation. Eighteen horses were randomly assigned to each of 3 groups. An osteochondral chip fragment was created in one randomly chosen intercarpal joint of each horse. Both intercarpal joints in the placebo control group (CNT) horses were injected with intra-articular administration (IA) of polyionic fluid. Both joints in the TA control group (TA CNT) horses were treated with 12 mg of TA in the intercarpal joint without an osteochondral fragment, and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. The TA treated group (TA TX) horses were treated with 12 mg of TA in the joint that contained the osteochondral fragment and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. All horses were treated IA on days 13 and 27 after surgery and exercised on a high speed treadmill for 6 weeks starting on Day 14. Horses in the TA TX group were significantly less lame than horses in the CNT and TA CNT groups. Horses in either TA CNT or TA TX groups had lower total protein, and higher hyaluronan, and glycosaminoglycan concentrations in synovial fluid than did those in the CNT group. Synovial membrane collected from subjects in TA CNT and TA TX groups had significantly less inflammatory cell infiltration, subintimal hyperplasia and subintimal fibrosis compared to the CNT group. Articular cartilage histomorphological parameters were significantly better from the TA CNT and TA TX groups compared to the CNT group. In conclusions, results from this study support favourable effects of TA on degree of clinically detectable lameness, and on synovial fluid, synovial membrane, and articular cartilage morphological parameters, both with direct intra-articular administration and remote site administration as compared to placebo treatment. The clinical use of IA administered TA in horses may be therapeutically beneficial in selected cases of osteochondral fragmentation and osteoarthritis.

Animals↗

PubMed1997

Effects of intravenous administration of sodium hyaluronate on carpal joints in exercising horses after arthroscopic surgery and osteochondral fragmentation.

OBJECTIVE: To evaluate the effects of arthroscopic surgery, osteochondral fragmentation, and treatment with IV administered hyaluronate on histologic, histochemical, and biochemical measurements within the carpal joints of horses. ANIMALS: 12 clinically normal horses, 2 to 7 years of age. PROCEDURE: Horses had an osteochondral fragment created at the distal aspect of the radiocarpal bone of 1 randomly chosen middle carpal joint to simulate osteochondral fragmentation. Horses were treated with 40 mg of hyaluronate or saline solution (placebo) intravenously once a week for 3 consecutive weeks (days 13, 20, and 27 after surgery). Treadmill exercise proceeded 5 days per week beginning 15 days, and ending 72 days, after surgery. Clinical evaluations were performed at the beginning and end of the study. Synovial fluid samples were obtained aseptically from both middle carpal joints on days 0, 13, 20, 27, 34, and 72 after surgery, and total protein, inflammatory cell, hyaluronate, glycosaminoglycan, and prostaglandin E2 concentrations were measured in each sample. All horses were euthanatized on day 72. Synovial membrane and articular cartilage were obtained for histologic evaluation. Articular cartilage samples were also obtained aseptically for determining glycosaminoglycan content and chondrocyte synthetic rate for glycosaminoglycans. RESULTS: Horses treated with hyaluronate intravenously had lower lameness scores (were less lame), significantly better synovial membrane histologic scores, and significantly lower concentrations of total protein and prostaglandin E2 within synovial fluid 72 days after surgery, compared with placebo-treated horses. Treatment with intravenously administered hyaluronate had no significant effects on glycosaminoglycan content, synthetic rate or morphologic scoring in articular cartilage, or other synovial fluid measurements. CONCLUSION: Intravenously administered hyaluronate appears to alleviate signs of lameness by interacting with synoviocytes, and by decreasing production and release of inflammatory mediators.

Animals↗

PubMed1996

Advances in equine arthroscopy.

Surgical procedures completed under arthroscopic guidance have become commonplace in many equine practices and have largely replaced surgery using arthrotomy incisions. With a limited amount of equipment, numerous diagnostic and surgical procedures can be completed. Surgeons need to become familiar with regional and intraarticular (intrasynovial) anatomy to ensure that proper surgical approaches are used, access to the lesion will be realized, and potential complications will be minimized. Specialized motorized instruments and surgical lasers are now available and may be useful in the treatment of selected clinical cases.

Animals↗

PubMed1996

Maintenance of equine articular cartilage explants in serum-free and serum-supplemented media, compared with that in a commercial supplemented medium.

OBJECTIVE: To evaluate the effects of a commercially defined, serum-free medium additive on equine articular cartilage explants, compared with effects of serum-free and serum-supplemented media. ANIMALS: Articular cartilage from a 3-year-old, mixed breed horse euthanatized for reasons other than musculoskeletal disease or sepsis. PROCEDURE: Media were changed every 48 hours, and the glycosaminoglycan (GAG) content was determined in media collected at each time point. Glycosaminoglycan synthesis by explant chondrocytes, and residual GAG content of articular cartilage (as a measure of explant GAG loss) were determined at the end of the study (day 8). RESULTS: Articular cartilage explants in serum-free medium and the commercial supplemented medium had significantly lower GAG synthesis and GAG content than did those incubated in serum-supplemented medium. There were no significant differences in GAG synthesis and content between serum-free and commercial supplemented medium groups. When comparing medium GAG content for all treatment groups, the GAG content in serum-free medium on day 8 was significantly greater than that in commercial supplemented medium, but significant differences were not evident in percentage of release of GAG (as an indicator of GAG degradation) among all 3 treatment groups. CONCLUSIONS: Commercial supplemented medium had effects on articular cartilage matrix GAG loss into medium equal to those of serum-supplemented medium (eg, both lost articular cartilage explant GAG to a similar degree). However, residual articular cartilage GAG content was higher in serum-supplemented medium, as was GAG synthesis. Commercial supplemented medium appears to either lack the proper ingredients to maintain steady-state GAG synthesis, or lacks proper concentrations of these ingredients.

Analysis of Variance↗

PubMed1995

Arthroscopic surgery for subchondral cystic lesions of the medial femoral condyle in horses: 41 cases (1988-1991).

Clinical signs, radiographic and arthroscopic findings, and outcome for 41 horses with subchondral cystic lesions of the medial femoral condyle treated by arthroscopic surgery were reviewed. There were 17. Quarter Horses, 15 Arabians, 8 Thoroughbreds, and 1 Holsteiner, with 28 (68%) of the horses being 1 to 3 years old. For all horses, the owners' complaint was mild to moderate hind limb lameness or an altered gait. Bilateral radiographic abnormalities of the medial femoral condyle were detected in 27 horses. Nineteen of the 27 horses had lesions identified bilaterally at arthroscopic surgery. In addition to the subchondral cystic lesion, 13 joints in 11 horses had an osteochondritis dissecans lesion on the articular surface of the medial femoral condyle that extended from the opening of the subchondral cystic lesion. Surgical debridement performed via arthroscopy was the only treatment for 37 lesions of 23 horses. Debridement followed by drilling of the defect bed was performed in 23 lesions of 18 horses. Complete follow-up information was obtained for 39 horses; 22 (56%) had a successful result and 17 (44%) had an unsuccessful result. In a separate analysis excluding horses with unsuccessful results because of factors not directly attributable to the subchondral cystic lesion of the medial femoral condyle, 23 of 31 (74%) horses had a successful result and 8 of 31 (26%) horses had an unsuccessful result.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Long-term fate and effects of exercise on sternal cartilage autografts used for repair of large osteochondral defects in horses.

Bilateral osteochondral defects (10 mm2 x 3 mm deep) were created on the distal articular surface of the radial carpal bone of ten, 2- to 3-year-old horses. One defect of each horse was repaired, using a sternal cartilage autograft (treated), and the other was left untreated (control). The horses were exercised on a high-speed treadmill at incrementally increased speed and duration over the course of 12 months. Horses were evaluated arthroscopically at 6 to 7 weeks, and clinical examinations were conducted weekly at exercise. Twelve months after surgery, carpuses of each horse were radiographed and clinically examined prior to euthanasia. A gross pathologic evaluation of each joint was conducted, and samples were collected for histologic, histochemical, histomorphometric, and biochemical evaluation. Radiographically, the grafted joints had more extensive evidence of arthropathy, and clinically, 8 of the 10 horses were more lame in the grafted limb. On the basis of histomorphometry, the repair tissue of the grafted defects contained a greater median percentage of hyaline cartilage (45%) than that of control defects (4.5%), and the control defects contained a greater percentage of fibrocartilage (82%) than did grafted defects (28.5%). A greater median percentage of repair tissue stained with safranin-O in the grafted defects (24.5%) than in the control defects (3.5%). On gross pathologic and histologic evaluation, repair tissue of the control defects had better continuity and was more firmly attached to the subchondral bone than was repair tissue of the grafted defects. Repair tissue of the grafted defects had extensive fissure and flap formation. Histologically, subchondral bone reactivity and fibroplasia was extensive in grafted joints. Repair tissue of grafted defects had a greater percentage of type II collagen (mean +/- SEM, 83.5 +/- 2.95%) than did controls (mean, 79.4 +/- 3.87%) that was not statistically significant. Hexosamine content was significantly higher (P < 0.05) in repair tissue of the grafted defect (mean, 28.9 +/- 3.00 mg/g of dry weight) vs control (mean, 20.6 +/- 1.85 mg/g of dry weight). On the basis of this experimental model, sternal cartilage autografts cannot be recommended at this time for repair of osteochondral defects in athletic horses.

Animals↗