Biomedical subjects

G L Tipoe

Publications and source records attributed to G L Tipoe.

At least 19 recordsLinked to original sources

PubMed2006

Inhibitors of inducible nitric oxide (NO) synthase are more effective than an NO donor in reducing carbon-tetrachloride induced acute liver injury.

The exact functional role of nitric oxide (NO) in liver injury is currently a source of controversy. NO is enzymatically synthesized by nitric oxide synthase (NOS). In this study, we assessed the role of inducible NOS (iNOS) in carbon tetrachloride (CCl4)-induced acute liver injury using inhibitors of iNOS, and an NO donor. Adult ICR mice were injected with CCl4 with or without the iNOS inhibitors (5-methylisothiourea hemisulfate [SMT] and l-N6-(1-iminoethyl)-lysine [L-NIL]) and an NO donor (Sodium Nitroprusside [SNP]). Blood and liver tissues were collected for analysis. Immunohistochemistry (IHC), serum alanine aminotransferase (ALT), serum total 8-isoprostane analysis, RT-PCR, Western Blotting (WB) and EMSA were done. Our results showed increased levels of ALT, necrosis, total 8-isoprostane and nitrotyrosine after CCl4 administration. iNOS inhibitors and SNP abrogated these effects but the effect was more pronounced with SMT and L-NIL. RT-PCR, WB and IHC in CCl4-treated mice demonstrated upregulation of TNF-alpha, iNOS, and COX-2. The administration of iNOS inhibitors with CCl4 diminished the expression of these proinflammatory mediators. NF-kappaB was also upregulated in CCl4-treated mice and was reversed in mice pretreated with iNOS inhibitors. SNP pretreated mice also showed a lower expression of COX-2 when compared with CCl4 treated mice but TNF-alpha, iNOS and NF-kappaB activity were unaffected. We propose that a high level of nitric oxide is associated with CCl4-induced acute liver injury and the liver injury can be ameliorated by decreasing the NO level with iNOS inhibitors and an NO donor with the former more effective in reducing CCl4-induced liver injury.

Alanine Transaminase↗

PubMed2005

Inhaled fluticasone in bronchiectasis: a 12 month study.

BACKGROUND: The clinical efficacy of inhaled corticosteroid (ICS) treatment has not been evaluated in bronchiectasis, despite the presence of chronic airway inflammation. METHODS: After three consecutive weekly visits, 86 patients were randomised to receive either fluticasone 500 mug twice daily (n = 43, 23F, mean (SD) age 57.7 (14.4) years) or matched placebo (n = 43, 34F, 59.2 (14.2) years) and reviewed regularly for 52 weeks in a double blind fashion. RESULTS: 35 and 38 patients in the fluticasone and placebo groups completed the study. Significantly more patients on ICS than on placebo showed improvement in 24 hour sputum volume (OR 2.5, 95% CI 1.1 to 6.0, p = 0.03) but not in exacerbation frequency, forced expiratory volume in 1 second, forced vital capacity, or sputum purulence score. Significantly more patients with Pseudomonas aeruginosa infection receiving fluticasone showed improvement in 24 hour sputum volume (OR 13.5, 95% CI 1.8 to 100.2, p = 0.03) and exacerbation frequency (OR 13.3, 95% CI 1.8 to 100.2, p = 0.01) than those given placebo. Logistic regression models revealed a significantly better response in sputum volume with fluticasone treatment than with placebo among subgroups of patients with 24 hour sputum volume <30 ml (p = 0.04), exacerbation frequency </=2/year (p = 0.04), and sputum purulence score >5 (p = 0.03). CONCLUSIONS: ICS treatment is beneficial to patients with bronchiectasis, particularly those with P. aerurginosa infection.

Administration, Inhalation↗

PubMed2004

Overexpression of iNOS and down-regulation of BMPs-2, 4 and 7 in retinoic acid induced cleft palate formation.

The present work studied the induction of cleft palate formation in embryos developed from pregnant BALB/c mice treated orally with retinoic acid (RA). Previous studies on mature somatic cell types showed that RA exerted inhibitory effects on inducible nitric oxide synthase (iNOS) production. For the first time, our study has shown that RA actually stimulates significant expression of iNOS at specific zones of the affected embryonic palatal tissues at three consecutive stages, from gestation day 13 (GD13) to day 16 (GD16). Enzymatically, iNOS facilitates intracellular nitric oxide (NO) synthesis from L-arginine. When NO reacts with reactive superoxides it may result in irreparable cell injury. NO was also reported to induce apoptosis in some mammalian cell systems. Based on our findings, we propose that such an increase in NO production might be associated with apoptosis in the embryonic palatal tissues in the RA-treated mice. The detrimental effects of NO resulted in a reduction in proliferating palatal cells and therefore disturbed the normal plasticity of the palatal shelves. With iNOS overexpression, our findings also showed that there was significant concomitant down-regulation in the expressions of Bone Morphogenetic Proteins (BMPs) -2, 4, and 7 with regional variations particularly in the palatal mesenchymal cells for those embryos developing cleft palate. Since specific spatial and temporal expressions of BMPs -2, 4, and 7 are critical during normal palatal morphogenesis, any deficiency in the epithelial-mesenchymal interaction may result in retarding growth at the embryonic palatal shelves. Taken together, our study has demonstrated cleft palate formation in the BALB/c embryos involved overexpression of iNOS and down-regulation of BMPs-2, 4 and 7.

Animals↗

PubMed2004

Bronchiectasis: not an orphan disease in the East.

Bronchiectasis is a common disease in the developing world. While the aetiology of bronchiectasis is diverse, many patients suffer from idiopathic disease. Although the pathogenesis of bronchiectasis is poorly understood, there are three distinct pathogenic elements, namely infection, inflammation and enzymatic actions. These interact to perpetuate airway destruction in many cases. There are four patient stereotypes: rapidly progressive, slowly progressive, indolent disease and haemoptysis-predominant. The diagnosis of bronchiectasis is best made with high resolution computed tomography, which should be followed by delineation of aetiology and evaluation of disease severity. Management of bronchiectasis is unsatisfactory and there are no disease-modifying drugs or treatment guidelines. Specific therapy to correct an underlying defect should be instituted whenever possible, although established disease often continues to deteriorate relentlessly. Treatment with prolonged, high-dose antibiotics is useful for exacerbations and probably also for some severely affected patients with frequent exacerbations who habour Pseudomonas aeruginosa in their airways. Commencement of long-term nebulised aminoglycoside, elective in-patient intravenous antibiotic therapy, long-term oral antibiotic or low-dose macrolide therapy requires special considerations. Inhaled corticosteroid therapy reduces chemokine expression in bronchiectasis in vivo, and may be useful for some patients. For severely affected patients, the use of non-invasive positive-pressure ventilation with supplementary oxygen sometimes helps. The lack of enthusiasm about bronchiectasis has already resulted in a lack of research in the treatment of this frustrating disease, and such research needs to be encouraged.

Asia↗

PubMed2004

Exhaled nitric oxide in bronchiectasis: the effects of inhaled corticosteroid therapy.

SETTING: While exhaled nitric oxide (eNO) levels are reduced by inhaled corticosteroid therapy in asthma, such treatment effect is unclear in bronchiectasis. DESIGN: Stable non-smoking bronchiectasis patients were randomised to receive either fluticasone (1 mg/daily) or identical placebo via the Accuhaler device. RESULTS: Sixty non-smoking patients (38 women; mean age 56.4 +/- 12.7 years) were recruited. Of these, half received inhaled fluticasone and half placebo therapy. eNO was measured using a chemiluminescence analyser at 0, 4, 12, 24, 36 and 52 weeks. There was no significant difference in eNO levels between fluticasone and placebo patients over the study period. There was no correlation between baseline eNO with age, FEV1, FVC, 24 h sputum volume or number of bronchiectatic segments. Patients with Pseudomonas aeruginosa (PA) infection, but not their counterparts, displayed a correlation between 0- and 52-week eNO levels. PA infection was associated with significantly lower eNO levels among the patients. CONCLUSIONS: Inhaled fluticasone therapy, despite being an effective anti-inflammatory agent, has no significant effect on eNO production, either at individual time points or over the entire 52-week profile, in bronchiectasis. It appears that eNO might not reflect the extent of airway inflammation in bronchiectasis.

Administration, Inhalation↗

PubMed2003

Down-regulation of aquaporin 3 in bronchiectatic airways in vivo.

Bronchiectasis is characterized pathologically by permanent abnormal bronchial dilation, and clinically by chronic sputum production. Aquaporin 3 (AQP3), a recently described water channel that is also found in large airway cell membrane, could play a role in the pathogenesis and particularly that of bronchorrhea in bronchiectasis. However, little is known of its in vivo distribution and physiological role in human airways. We have, therefore, performed this quantitative immunohistochemistry study on endobronchial biopsies to evaluate the expression and clinical relevance of AQP3 in patients with idiopathic bronchiectasis (n = 25, 15 F, 64.3 +/- 11.5 years) and control subjects (n = 14, 5 F, 57.5 +/- 12.0 years). Quantitative image analysis was performed to evaluate the expression of AQP3 in the bronchial epithelial cells. Our results show that AQP3 was predominantly expressed in the basal cells of the epithelial layer in both groups. Expression of AQP3 was significantly reduced in the basal, but not columnar, epithelial cells in bronchiectasis compared with control airways (p = 0.02, 0.35). Only bronchiectatic patients with regular sputum production, but not their counterparts, had significant downregulation of epithelial AQP3 expression compared with control airways (p = 0.004, 0.24). Our findings suggest that AQP3 could have an important role in the pathogenesis of increased mucus production in bronchiectasis.

Aquaporin 3↗

PubMed2003

Pseudomonas aeruginosa adherence to human basement membrane collagen in vitro.

The mechanisms for Pseudomonas aeruginosa colonisation in the airways of patients with bronchiectasis and cystic fibrosis are poorly understood. P. aeruginosa could evade mucociliary clearance by adhering to the basement membrane at areas denuded of intact respiratory epithelium. The authors have developed an in vitro model to study P. aeruginosa adherence to human basement membrane type-IV collagen by using scanning electron microscopy. P. aeruginosa adherence density was determined as the number of P. aeruginosa per 20 microscope fields (2,000x) to log inocular size after incubation at 37 degrees C for 45 min. The presence of phytohaemagglutinin (PHA)-E, which binds specifically to D-galactose-beta1-4-D-N-acetylglucosamine, significantly reduced P. aeruginosa adherence density compared with control. The presence of heparin and calcium also significantly reduced P. aeruginosa adherence density. P. aeruginosa adherence was not affected by the presence of proline, trans-hydroxyproline, glycine, galactose, N-acetylneuraminic acid, N-acetylglucosamine or Arachis hypogea. Pseudomonas aeruginosa adherence probably acts via recognition of the D-galactose-beta1-4-D-N-acetylglucosamine sequence on type-IV collagen and this process could be inhibited by heparin and calcium. As persistent Pseudomonas aeruginosa colonisation is detrimental to patients with cystic fibrosis and bronchiectasis and there is currently no effective treatment for its eradication, these results could lead to novel therapy for persistent Pseudomonas aeruginosa infection.

Amino Acids↗

PubMed2003

[Expression of CNTFs in facial motoneurons during facial nerve regeneration in rats and their association with TGF-beta and rhBMP-2].

OBJECTIVE: The aim of this study was to observe the expression of ciliary neurotrophic factors (CNTFs) in the facial motor neurons in rats during facial nerve regeneration. METHODS: The expression amount of CNTFs in eight groups was determined with immunohistochemical staining and image analysis. RESULTS: The expression of CNTFs increased during the process of nerve regeneration, and reached the maximum one-week and one-month after nerve injury respectively. After one month, the intensity of CNTFs reduced gradually. The expression of recombinant human bone morphogenetic protein-2 (rhBMP-2) did not show distinct difference comparing with the control, but beta transforming growth factors (TGF-beta) benefited the expression of CNTFs during nerve regeneration. CONCLUSION: The endogenous CNTFs promotes the axon outgrow during regeneration, and TGF-beta promotes the expression of CNTFs to rescue motoneuron during facial nerve regeneration.

Animals↗

PubMed2002

Overexpression of matrix metalloproteinase-8 and -9 in bronchiectatic airways in vivo.

The progressive bronchial dilatation in bronchiectasis is likely to be the result of continued airway matrix destruction, although little is known about the role of neutrophil matrix metalloproteinases (MMPs) in this process. Immunohistochemistry has been used to investigate the expression and cellular localisation of MMP-8 and MMP-9 in bronchiectatic airways in vivo. Endobronchial biopsies were taken from 25 bronchiectatic patients, and from the right lower lobe in 14 control subjects. MMP-8, MMP-9, neutrophils and macrophages were stained with monoclonal antibodies and quantified as positive cell x mm(-2) of the lamina propria by using an image analysis system. There were significantly higher densities of MMP-8 and MMP-9 positive cells in the lamina propria of bronchiectatic than control airways. In bronchiectatic airways, the densities of MMP-8 and MMP-9 positive cells correlated with each other and with neutrophil density, but not with macrophage density. In control airways, a significant correlation was found between MMP-8 with neutrophil and MMP-9 with macrophage densities. An overexpression of neutrophil matrix metalloproteinases in bronchiectatic airways could help explain the continuation of airway destruction in bronchiectasis. In view of the clinical availability of matrix metalloproteinase antagonists, the results presented here could have a significant impact on the development of novel therapies of this untreatable disease.

Aged↗

PubMed2001

Exhaled nitric oxide: the effects of age, gender and body size.

Since little is known of the effects of age, gender, and body size on exhaled nitric oxide (NO) production, we have conducted a prospective study to examine these factors in a healthy nonsmoking women (mean age +/- SD 47.7 +/- 15.8, range 20-79 years). Exhaled NO was measured by an automatic chemiluminescence analyzer (Sievers NO Analyser 280) at steady expiration. Men had significantly higher exhaled NO levels than women (p = 0.001). Although exhaled NO levels did not correlate with age (r = 0.12, p = 0.17), it correlated significantly with height (r = 0.23, p = 0.02), weight (r = 0.34, p

Adult↗

PubMed2001

Effects of combination of angiotensin-converting enzyme inhibitor and angiotensin receptor antagonist on inflammatory cellular infiltration and myocardial interstitial fibrosis after acute myocardial infarction.

OBJECTIVES: The goal of this study was to compare the relative efficacy of an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin receptor blocker (ARB) in suppressing the histopathologic changes that lead to ventricular remodeling after an acute myocardial infarction (AMI). BACKGROUND: Myocardial interstitial fibrosis in the noninfarcted region is a major histologic landmark resulting in cardiac dysfunction after AMI. However, the relative potency of an ACE inhibitor and ARB on suppressing the histopathologic changes was unclear. METHODS: Rats with AMI were randomized to fosinopril, valsartan or a combination of the two drugs for two or four weeks. The total, type I and type III collagen and activated fibroblasts and macrophages were quantified by histomorphometry. The expression of transforming growth factor-beta 1 (TGF-beta 1) messenger ribonucleic acid (mRNA) was determined by reverse transcription polymerase chain reaction. RESULTS: Acute myocardial infarction resulted in significant elevation of total (p < 0.001) and type I (p < 0.001) collagen and a twofold increase in TGF-beta 1 mRNA expression (p < 0.001) in the septum at two and four weeks. Macrophages and activated myofibroblasts infiltrated extensively in the infarct zone. Treatment with valsartan or combination therapy normalized the total and type I collagen (p < 0.001) as well as TGF-beta 1 mRNA level (p < 0.01) in the septum and was associated with the suppression of macrophages and myofibroblasts in the infarct zone (p < 0.01). Fosinopril was less effective than valsartan or combination therapy. CONCLUSIONS: The use of valsartan, especially combined with fosinopril, was more effective than fosinopril in the suppression of histopathologic changes resulting in cardiac remodeling after AMI. This study has important therapeutic implications in pharmacotherapy of clinical practice.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Overexpression of BMP-2/4, -5 and BMPR-IA associated with malignancy of oral epithelium.

The aim of the present study was to determine the relationships between bone morphogenetic proteins (BMPs), BMP receptor type IA and carcinogenesis of oral epithelium. A retrospective study was performed on material obtained from oral mucosa, including nine cases of normal mucosa (NB), eight cases of nonspecific chronic inflammation (NCI), seven cases of hyperkeratosis (HK), five cases of squamous cell papilloma (SCP), 29 cases of squamous cell carcinoma (SCC) with various grades of differentiation and 10 cases of epithelium adjacent to carcinoma (EAC). Six cases of NB from hard palate (NHP) were chosen as a control group. The benign groups consisted of NCI, HK and SCP. The antibodies against BMP-2/4, -5, receptor BMPR-IA and purified bovine BMP (bBMP-McAb) were utilised using an immunocytochemical method. The results demonstrated that the immunostaining of BMP-2/4, BMP-5, BMPR-IA and bBMP-McAb was weak and not consistent in normal and benign groups. The immunoreactivity level was independent of the clinical and pathological grading of SCC. All cases of SCC showed positive staining for BMP-2/4, BMP-5, BMPR-IA and bBMP-McAb except for three cases and one case of SCC which negatively stained for BMP-2/4 and BMP-5, respectively. The staining intensity and proportion of the positively stained cells were markedly increased in SCC when compared with that of the normal and benign groups except for EAC. The metastatic carcinoma cells in lymph nodes were strongly and positively stained for BMP-2/4 and BMP-5 when compared with the primary lesions. Our results indicate that there was an overexpression of BMP-2/4, BMP-5, bBMP-McAb and BMPR-IA in the high-risk premalignant and malignant lesions of oral epithelium. Our findings suggest that BMP-2/4 and BMP-5 but not BMPR-IA might be involved in the metastasis of oral carcinoma cells.

Analysis of Variance↗

PubMed2001

Macrophages, neutrophils and tumour necrosis factor-alpha expression in bronchiectatic airways in vivo.

Bronchiectasis is increasingly being recognized as an inflammatory condition of the airways in which pathological permanent dilation occurs. We have obtained endobronchial biopsies in 14 patients with stable bronchiectasis and 15 control subjects. Airway neutrophils, macrophages and tumour necrosis factor-alpha (TNFalpha)-positive cells were stained with monoclonal antibodies and the densities of positive cells in the lamina propria were determined by using a computer image analyser. There was significantly higher neutrophil, macrophage and TNFalpha-positive cell densities in the lamina propria of bronchiectatic than control airways (P < 0.001, P < 0.001 and P=0.0002, respectively). Airway neutrophil density in bronchiectasis but not in controls, correlated with TNFalpha-positive cell density (r=0.71, P=0.004). A significant correlation between airway macrophage and TNFalpha-positive cell densities was demonstrated in both control and bronchiectatic airways (r=0.63, P=0.016 and r=0.60, P=0.02 respectively). Neutrophil density negatively correlated with per cent forced vital capacity (FVC%) predicted among patients with bronchiectasis (r=-0.53, P=0.04). Bronchiectasis patients who were regular sputum producers had a significantly higher macrophage, but not neutrophil density than their counterparts (P=0.02 and P=0.48 respectively). Our original findings suggest that airway macrophages could contribute to neutrophil influx into airway walls through their production of TNFalpha and therefore play an important role in the pathogenesis of bronchiectasis.

Aged↗

PubMed2001

Macrophage migration inhibitory factor expression in male and female ethanol-fed rats.

Macrophage migration inhibitory factory (MIF) regulates macrophage accumulation at sites of injury and can promote the inflammatory response. We studied MIF expression in the intragastric feeding rat model for alcoholic liver injury. Male and age-matched female rats were fed ethanol or dextrose with fish oil. Two groups of male rats were fed medium-chain triglycerides with ethanol or dextrose. Analysis of liver histopathology, lipid peroxidation, endotoxin, mRNA, and immunohistochemistry for MIF, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were carried out. Male and female rats fed fish oil and ethanol showed necroinflammatory liver injury and had the highest expression of MIF, TNF-alpha, and IFN-gamma in the liver. Decreased levels of MIF protein were seen in rats with higher endotoxin levels, suggesting that preformed MIF is released into the circulation. MIF is an important mediator of the inflammatory response in alcoholic liver disease and a potential therapeutic target.

Administration, Oral↗

PubMed2001

Increased severity of alcoholic liver injury in female rats: role of oxidative stress, endotoxin, and chemokines.

Alcoholic liver injury is more severe and rapidly developing in women than men. To evaluate the reason(s) for these gender-related differences, we determined whether pathogenic mechanisms important in alcoholic liver injury in male rats were further upregulated in female rats. Male and age-matched female rats (7/group) were fed ethanol and a diet containing fish oil for 4 wk by intragastric infusion. Dextrose isocalorically replaced ethanol in control rats. We analyzed liver histopathology, lipid peroxidation, cytochrome P-450 (CYP)2E1 activity, nonheme iron, endotoxin, nuclear factor-kappa B (NF-kappa B) activation, and mRNA levels of cyclooxygenase-1 (COX-1) and COX-2, tumor necrosis factor-alpha (TNF-alpha), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-2 (MIP-2). Alcohol-induced liver injury was more severe in female vs. male rats. Female rats had higher endotoxin, lipid peroxidation, and nonheme iron levels and increased NF-kappa B activation and upregulation of the chemokines MCP-1 and MIP-2. CYP2E1 activity and TNF-alpha and COX-2 levels were similar in male and female rats. Remarkably, female rats fed fish oil and dextrose also showed necrosis and inflammation. Our findings in ethanol-fed rats suggest that increased endotoxemia and lipid peroxidation in females stimulate NF-kappa B activation and chemokine production, enhancing liver injury. TNF-alpha and COX-2 upregulation are probably important in causing liver injury but do not explain gender-related differences.

Animals↗

PubMed2001

The effect of aging on nasal mucociliary clearance, beat frequency, and ultrastructure of respiratory cilia.

The increased susceptibility of the elderly to lower respiratory tract infection cannot be fully explained. Although mucociliary clearance, which is affected by ciliary beating and ultrastructure, plays a crucial role in the defense of the airways against inhaled microbes, little is known of the effects of aging on these parameters. We studied the nasal mucociliary clearance (NMCC) time, ciliary beat frequency, and ultrastructure of respiratory cilia in a cohort of healthy volunteers (age range 11 to 90 yr). Ciliary beat frequency of ciliated nasal epithelial cells was obtained via an established photometric method, and NMCC time was measured with the saccharine test. There was a correlation of ciliary beat frequency (r = -0.48, p = 0.0001) and NMCC time r = 0.64, p < 0.001) with increasing age. Transmission electron microscopy revealed an increase in the percent of subjects exhibiting microtubular disarrangement and single central microtubules with aging (p = 0.002 and p = 0.005, respectively). Subjects older than 40 yr of age had significantly slower ciliary beat frequency, higher percent of ciliary cross-sections displaying single tubules, and longer NMCC time than their younger counterparts (p < 0.05). These findings may help explain the frequent occurrence of respiratory infection in the elderly.

Adolescent↗

PubMed2001

Transcriptional mRNA of BMP-2, 3, 4 and 5 in trigeminal nerve, benign and malignant peripheral nerve sheath tumors.

The aim of our study was to document whether relationships existed among bone morphogenetic proteins (BMPs), peripheral nerve and neoplastic lesions of nerve sheath tumors. The mRNA transcriptions of BMP-2, 3, 4 and 5 in 10 cases of schwannoma, three cases of malignant schwannoma and two cases of trigeminal neuralgia were detected using an in situ hybridization technique. Our results demonstrated that the myelin sheaths of Schwann cell from the peripheral neuroectomy of trigeminal neuralgia positively expressed mRNA of BMP-2, 3, 4, and 5. The most interesting finding was that the nerve fibers of trigeminal nerve showed only BMP-2 positive staining. All of the neoplastic lesions of nerve sheath showed a consistent but variant expression of BMP-2, 3, 4, and 5. The expression signals of BMP-2, 3, 5 mRNA in malignant schwannoma were relatively lower than in benign lesions except for the expression of BMP-4 mRNA. Our results indicated that selected members of BMPs were expressed in the peripheral nerves that might contribute to the health maintenance, proliferation, regeneration and neoplastic transformation of the peripheral nerve system. Furthermore, the effects of BMP-2, 3, 4 and 5 on peripheral nervous system during neoplastic transformation might be widespread, diverse and antagonistic.

Adult↗

PubMed2001

Alteration of apoptosis in cleft palate formation and ectomesenchymal stem cells influenced by retinoic acid.

It has been shown that apoptosis is involved in normal embryonic development. The aim of the present study was to elucidate the role and alteration of apoptosis in the pathogenesis of cleft palate induced by retinoic acid (RA) and the ectomesenchymal stem (EMS) cells influenced by RA. RA was administered by gavage to pregnant C57BL/6N strain mice in the experimental group, and the control group received oil alone. Pregnant mice were killed at set periods of time thereafter and histologically analyzed. EMS cells explanted from the palatal shelves of embryonic mice were cultured and characterized by immunohistochemistry, growth curves and population-doubling time. The alterations of apoptosis of EMS cells and developing palatal shelves influenced by RA were evaluated by the terminal deoxynucleotidyl transferase-mediated UTP-biotin nick end-labeling (TUNEL) method. RA-treated mice showed formation of cleft palates resulted from the small size of the palatal shelves and their failure to lift. TUNEL staining showed that the number of apoptotic mesenchymal cells in palatal shelves in the RA-treated mice was increased significantly when compared with the control group. The primary culture of EMS cells proceeded successfully. The population-doubling time of RA-treated cells was much longer compared with non-treated EMS cells. RA also dramatically increased the number of apoptotic cells in EMS cells in vitro. We concluded that EMS cells are the crucial cells in palate development. RA could inhibit the proliferation and induced the apoptosis of EMS cells. The inhibition of growth and excess apoptosis of EMS cells may contribute to the formation of cleft palate and other orofacial congenital malformations.

Animals↗