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D M Hyde

Publications and source records attributed to D M Hyde.

At least 19 recordsLinked to original sources
PubMed1992

Computer-assisted morphometry: point, intersection, and profile counting and three-dimensional reconstruction.

The use of computers in morphometry can involve 1) automated image analysis, semiautomated image analysis and point, intersection, intercept and profile counts of two-dimensional images on tissue sections with mathematical extrapolation to the third dimension, 2) direct measurement of volumes, surfaces, lengths, and curvature using x,y,z coordinates of serial sectioned images, or 3) stereologic techniques and serial sections which is a combination of 1 and 2 above. Automated and semiautomated image analysis are generally restricted to specimens that are characterized by differential contrast such as interalveolar septa in the lung or histochemically stained mucous granules in pulmonary epithelium. Point, intersection, and profile counts using hand-held, notebook PCs, portable PCs, or standard PCs and MS-DOS-based application programs are extremely efficient, precise, affordable, and convenient methods of quantitating average values of a population. When morphometric measurements of individual structures are required, computer-assisted three-dimensional reconstruction using x,y,z coordinates of the surface outline from serial sections is a tedious yet precise method. We describe a computer program that efficiently estimates mean caliper diameter, volume, and surface area with less than five percent error with five sections per structure. We also describe a program that does digital image subtraction on serial sections, superimposes digitally generated test systems on biological images, and accumulates point, intersection, and profile counts using a Macintosh II series computer.

Animals↗
PubMed1992

Effects of dibutyrylcyclic adenosine monophosphate on bleomycin-induced lung toxicity in hamsters.

Cyclic nucleotides play an important role in the regulation of fibroblast proliferation and collagen metabolism. In the present study, the antifibrotic potential of dibutyrylcAMP (Bt2cAMP) was evaluated in the bleomycin (BLM)-hamster model of pulmonary fibrosis. Bt2cAMP (10 mg kg-1, s.c.) or saline (SA, s.c.) was given daily two days prior to the first intratracheal (i.t.) dose of BLM or SA and thereafter throughout the study. BLM or SA was instilled i.t. in three consecutive doses (2.5, 2.0 and 1.5 U 5ml-1 kg-1) at weekly intervals. Hamsters were killed at 7, 14 and 20 days after the third i.t. instillation. Bt2cAMP significantly reduced the contents of lung hydroxyproline and lung thiobarbituric acid reactive substance equivalents in BLM-treated animals at 7 and 14 days. Bt2cAMP significantly elevated lung superoxide dismutase activity in BLM-treated animals at 7 days. Lung prolyl hydroxylase activity was significantly elevated at 14 and 20 days in SABLM- and Bt2cAMPBLM-treated animals. The ratio of cAMP/cGMP was significantly reduced at all time points in SABLM-treated animals but only at 7 and 14 days in Bt2cAMPBLM-treated animals. Bt2cAMP caused no significant changes in lung calcium and calmodulin levels and protein content of the bronchoalveolar lavage. BLM significantly increased various inflammatory cell counts in the lavage at all three time points. The cell counts in the Bt2cAMPBLM groups were generally lower at 7 days and higher at 20 days than those of the SABLM groups. Histological evaluation showed that the lungs of Bt2cAMPBLM-treated hamsters progressed from an inflammatory cell lesion to a fibrotic lesion at a slower rate than the SABLM groups. It was concluded that Bt2cAMP attenuated BLM-induced pulmonary fibrosis in hamsters in part by delaying the acute phase of the inflammatory reaction.

Animals↗
PubMed1992

Double-stranded RNA regulation of DNA synthesis in fibroblasts.

The double-stranded RNA molecule polyinosinic-polycytidylic acid (poly IC) has been found in some studies to have a mitogenic effect on fibroblast proliferation while other studies found poly IC to have an inhibitory effect on proliferation. In this study, we investigated whether a stabilized form of poly IC complexed with poly-L-lysine and carboxymethylcellulose (poly ICLC) had a bidirectional effect on DNA synthesis in fibroblasts from four different cell lines and determined factors that potentially influence this bidirectional effect. In medium containing fetal bovine serum, poly ICLC slightly increased the levels of [3H]thymidine incorporation in growing fibroblasts in three of the four fibroblast cell lines tested, while poly ICLC increased [3H]thymidine incorporation in confluent, quiescent fibroblasts in two of four cell lines. Poly ICLC did not induce DNA synthesis in subconfluent, quiescent or in confluent, quiescent fibroblasts under serum-free conditions. Poly ICLC significantly suppressed serum-induced [3H]thymidine incorporation by quiescent fibroblasts in all cell lines. We conclude that the stimulatory and inhibitory effects of poly ICLC on DNA synthesis are influenced by both the cell line and the presence of serum components in the culture medium but not by population density.

Animals↗
PubMed1992

Acute ozone-induced lung injury in neutrophil-depleted rats.

To test the hypothesis that neutrophils contribute to acute, ozone-induced epithelial damage in the lung, rats were depleted of their circulating neutrophils by intraperitoneal injection of a rabbit anti-rat neutrophil serum (ANS) 12 hr prior to an 8-hr exposure to 1.0 ppm ozone. Additional rats were given an injection of normal rabbit serum (NRS) prior to ozone exposure. Exposures were followed by postexposure periods in filtered air for 0, 4, or 16 hr. Control rats were given either ANS or NRS and then exposed only to filtered air. Analysis of bronchoalveolar lavage fluid (BALF) from NRS-treated rats revealed a significant increase in total neutrophils above that of controls at the 4- and 16-hr postexposure times, with a peak increase at 4 hr postexposure. In contrast, there was almost total ablation of the BALF neutrophil response in the ANS-treated rats at all times. Ozone caused an increase in BALF protein, fibronectin, and interleukin-6 above those in controls in both the NRS- and ANS-treated rats, but the only significant difference between the two groups was a level of fibronectin in the neutrophil-depleted animals higher than that in the neutrophil-sufficient animals at the 0-hr postexposure time. Electron microscopic morphometry on lungs fixed by intravascular perfusion demonstrated no significant differences in the volume per surface area epithelial basal lamina (Vs) of necrotic and degenerating epithelial cells in central acini between the neutrophil-depleted and neutrophil-sufficient animals. From these results, we concluded that neutrophils do not play a detectable role in contributing to the early epithelial damage in the lung caused by an acute exposure to ozone.

Animals↗
PubMed1992

Pulmonary inflammation and epithelial injury in response to acute ozone exposure in the rat.

To document the time course of the inflammatory response and epithelial injury in the lung following an acute ozone exposure, rats were exposed to 1.0 ppm ozone for periods between 4 and 24 hr. Some of the exposures were followed by postexposure periods in filtered air for up to 20 hr. Bronchoalveolar lavage fluid (BALF) analysis and electron microscopic morphometry on centriacinar regions of lungs fixed by intravascular perfusion were used to assess the degree of pulmonary inflammation and epithelial cell necrosis. Total protein and numbers of neutrophils and epithelial cells in BALF increased as the duration of ozone exposure increased, while BALF macrophages decreased. Quantitation of the neutrophil response in centriacinar lung regions (capillary, interstitial, and epithelial/luminal compartments of the terminal bronchiole and proximal alveolar duct) by morphometry generally correlated with the BALF analysis, and revealed a greater volume per surface area epithelial basal lamina (Vs) of neutrophils in the terminal bronchiole compartments compared to proximal alveoli. Necrosis of epithelial cells in terminal bronchioles, primarily ciliated cells, occurred as early as 4 hr after initiation of ozone exposure, before marked neutrophil migration, and continued during periods of maximal neutrophil influx. We concluded that the early epithelial necrosis in terminal bronchioles during the first few hours of ozone exposure was primarily due to direct ozone toxicity, but could not rule out the possibility of neutrophils contributing to the injury at later time points, especially between 8 and 12 hr of exposure (during periods of maximal neutrophil migration).

Animals↗
PubMed1992

Effects of an interferon inducer bropirimine on bleomycin-induced lung fibrosis in hamsters.

The antifibrotic effect of an interferon inducer, bropirimine (2-amino-5-bromo-6-phenyl-4(3H)-pyrimidinone, ABPP) was evaluated in bleomycin (BLM)-hamster model of lung fibrosis. ABPP is an orally active biological response modifier and has immunomodulatory, antiviral, and antineoplastic activities. The hamsters were randomized in four groups and treated with either bropirimine (100 mg/kg, intraperitoneally) suspended in carboxymethylcellulose (CMC, 10 mg/10 mg/ml) or CMC alone each day for sixteen days. After two days, the hamsters received either single bolus of BLM (7.5 U/5 ml/kg) or an equivalent volume of saline by the transoral endotracheal route. Groupings were assigned as: CMC + saline (CS), ABPP + saline (AS), CMC + BLM (CB) and ABPP + BLM (AB). Animals were sacrificed at fourteen days after intratracheal installation of either BLM or saline. Their lungs were lavaged and processed for morphometric and biochemical studies. ABPP had little effect in preventing BLM-induced weight loss and lung injury. ABPP was found to reduce the BLM-induced accumulation of collagen in the lung as measured by hydroxyproline content. The hamsters in AB group had significantly less collagen than the hamsters in CB group: 995 and 1157 micrograms hydroxyproline/lung, respectively. Administration of ABPP prevented the BLM-induced increase in the lung prolyl hydroxylase activity. The total number of monocytes and eosinophils recovered from the bronchoalveolar lavage fluid (BALF) of the AB group were significantly lower than that of the animals in CB group. However, the BALF supernatant protein content from animals in AB group (7.9 mg/lung) was significantly higher than that of CB group (4.5 mg/lung).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Functional and morphologic changes caused by acute ozone exposure in the isolated and perfused rat lung.

Ozone has been shown to increase airway resistance and/or airway reactivity in vivo in animals and humans. Because of the complexities inherent in studying this phenomenon in whole animals, we developed a model of ozone-induced effects on airway physiology using the isolated perfused rat lung. Rat lungs were suspended in an airtight chamber and perfused via the pulmonary circulation with a modified Krebs-Henseleit buffer containing 4.5% bovine albumin. Ventilation of the lungs was achieved by generating a fluctuating negative pressure within the chamber (-2 to -7 cm H2O) at a rate of 60 breaths/min. The lungs were ventilated with humidified 95% air and 5% CO2 alone (control condition) or mixed with ozone at 1.0 or 2.0 ppm. Transpulmonary pressure, flow rate, and tidal volume were recorded at 0, 1, 2, and 3 hours, and pulmonary resistance (RL) and dynamic compliance (Cdyn) were calculated. There was no significant difference in lung weight/total body weight ratios between the three groups at the end of the 3-h period. RL increased and Cdyn decreased in a time- and dose-dependent manner with ozone exposure. The percent increase above baseline in RL +/- SEM at 3 h was 9.4 +/- 4.1% for control lungs, 21.0 +/- 3.2% for 1.0 ppm ozone-exposed lungs, and 63.6 +/- 13.5% for 2.0 ppm ozone-exposed lungs. The percent decrease below baseline in Cdyn +/- SEM at 3 h was 27.4 +/- 2.1% for control lungs, 37.1 +/- 2.7% for 1.0 ppm ozone-exposed lungs, and 55.2 +/- 7.3% for 2.0 ppm ozone-exposed lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1992

Idiopathic pulmonary fibrosis. Quantitative assessment of lung pathology. Comparison of a semiquantitative and a morphometric histopathologic scoring system.

The objective of this study was to determine the accuracy of a semiquantitative method of assessing the relative degree of cellularity and fibrosis compared with a morphometric analysis of specific histopathologic features in idiopathic pulmonary fibrosis (IPF). Morphometric analysis was performed on biopsy tissue from 20 patients. Morphometry showed that approximately 70% of parenchymal tissue was abnormal: 35% cellular consolidation and fibrosis, 20% honeycomb changes, 10% thick alveolar septa, and 5% small airways within abnormal parenchymal tissue. The prominent components of the abnormal parenchymal tissue were extracellular fibers, an abundance of interstitial cells, and epithelial cell hyperplasia. Correlation between four groupings of pathologic features, identified by a semiquantitative analysis, and each of the components of the parenchymal lesions showed significant correlations between (1) the fibrotic or reparative factor (alveolar wall metaplasia, fibrosis, honeycombing, and smooth muscle and vascular changes) and components of honeycomb lesions (extracellular fibers, interstitial cells, and epithelial injury and repair), and (2) the inflammatory and exudative factor and extracellular fibers in the lesions. These results support that the scoring system used by the pathology panel provides an accurate assessment of pathologic features useful in the assessment of the extent and severity of the histopathologic lesions of IPF.

Biopsy↗
PubMed1992

Ozone-induced acute tracheobronchial epithelial injury: relationship to granulocyte emigration in the lung.

To investigate the relationship between granulocyte emigration and epithelial injury in specific airway generations of the tracheobronchial tree following short-term ozone exposure, we exposed rhesus monkeys for 8 h to 0.00 (controls) or 0.96 ppm ozone with post-exposure periods of 1, 12, 24, 72, and 168 h in filtered air before necropsy. There were five control and three exposed monkeys for each of the post-exposure times for a total of 20 monkeys. Neutrophils isolated from peripheral blood and labeled with 111In-tropolonate were infused in the cephalic vein in unanesthetized monkeys (except the 1-h group) 4 to 5 h before necropsy. The trachea and microdissected bronchi (fourth and ninth generations) and respiratory bronchioles (fifteenth generation) from the right upper lobe of each monkey were examined by electron microscopy. Labeled neutrophil influx into lung tissue and bronchoalveolar lavage fluid (BALF) was maximal at 12 h and returned to baseline by 24 h after exposure. This was in contrast to total neutrophils (labeled and unlabeled) in BALF, which were significantly elevated through 24 h after exposure but returned to baseline by 72 h. Lavage protein was significantly elevated at 24 h after exposure but was at control levels at all other times. Morphometric observations showed epithelial necrosis at 1 and 12 h in the trachea and bronchioles but continued to be observed in significant numbers at 24 h after exposure in bronchi. A significant increase in the labeling index of epithelial cells was observed at 12 h only in bronchi. Epithelial necrosis and repair was associated with the presence of granulocytes in the epithelium and interstitium of all airway levels. However, eosinophils were maximally increased in the epithelium and interstitium of bronchi at 24 h after exposure when epithelial necrosis was maximal in these airways and when lavage protein was significantly elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The role of the nonciliated bronchiolar epithelial (Clara) cell as the progenitor cell during bronchiolar epithelial differentiation in the perinatal rabbit lung.

Although it is well established that the nonciliated bronchiolar epithelial (Clara) cell serves as the progenitor for itself and ciliated cells in the adult lung following bronchiolar epithelial injury, the nature of this relationship during development has not been well characterized. To define the pattern of proliferation and differentiation of bronchiolar ciliated and nonciliated cells, lungs of fetuses and offspring from time-mated New Zealand White rabbits, ranging in age from 24 days of gestation to 25 wk postnatal (PN), were fixed by airway infusion and embedded for simultaneous light and transmission electron microscopy. Three categories of cells could be distinguished in terminal bronchioles: nonciliated cells with abundant glycogen and variable numbers of organelles; nonciliated cells with little glycogen, large numbers of polyribosomes, and variable numbers of basal bodies; and ciliated cells with cilia of varying height. Together, both types of nonciliated cells were 100% of the epithelium at 24 and 27 days gestation age (DGA). At 30 days DGA, they were 85% of the population; at all postnatal ages, they ranged from 75 to 81% of the total population. Nonciliated cells with polyribosomes and basal bodies were 10 to 20% of the total nonciliated cell population between 24 DGA and 1 wk PN and not found thereafter. Ciliated cells were not observed in animals younger than 30 DGA. Labeling indices of bronchiolar epithelium in fetuses of pregnant rabbits injected with tritiated thymidine, as determined by autoradiography, were 57 cells per thousand at 28 DGA (1 h postinjection [PI]), 76 at 29 DGA (24 h PI), and 114 at 30 DGA (48 h PI).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Development of a bleomycin hamster model of subchronic lung fibrosis.

The existing bleomycin (BLM)-rodent model of lung fibrosis requires large doses and is often associated with morbidity and high mortality. We have developed an intratracheal multiple-dose BLM-hamster model of lung fibrosis. In this model, 3 consecutive doses of BLM (2.5 U, 2.0 U and 1.5 U/5mL/kg) were instilled intratracheally, one dose per week. The hamsters were killed at 10, 20, 30, 60 and 90 days after the last IT instillation and the lungs were lavaged or perfused with saline. This regimen of BLM administration was devoid of morbidity and caused only 6% overall mortality. Lung prolyl hydroxylase activity at 10 days and hydroxyproline content at 20, 30, 60 and 90 days were significantly higher than noted for the controls. Bronchoalveolar lavage fluid-supernatant protein and the total number of recovered cells of all types were significantly higher than observed for the controls at all times, except at 90 days. Lungs showed a multifocal mixed mononuclear infiltrate at 10 and 20 days and septal fibrosis, which was most severe and organized at 30 days and less severe at 60 and 90 days. The parenchymal lesions were significantly greater than those of the controls at all times, except at 10 days. This model, which required only 6 U BLM/kg, induced a moderate level of lung fibrosis. It has been concluded, therefore, that this model, inasmuch as it is not associated with an overwhelmingly acute inflammation, would be more applicable for screening potential antifibrotic agents than existing models of lung fibrosis.

Animals↗
PubMed1992

Abatement of bleomycin-induced increases in vascular permeability, inflammatory cell infiltration, and fibrotic lesions in hamster lungs by combined treatment with taurine and niacin.

BACKGROUND: The bleomycin (BL) hamster model of interstitial pulmonary fibrosis has been widely used to study the pathogenesis of interstitial pulmonary fibrosis and to screen potentially desirable antifibrotic agents. We have recently shown that taurine and niacin in combination, diminished BL-induced increases in lung lipid peroxidation and hydroxyproline content in hamsters. In the present study, we have evaluated the effects of taurine and niacin on the bronchoalveolar lavage (BAL) cells, and morphologic and morphometric features of the lung in the same model of pulmonary fibrosis. EXPERIMENTAL DESIGN: The hamsters were divided into 4 groups: saline; taurine + niacin + saline; BL; and taurine + niacin + BL. Treatment of taurine and niacin began 2 days before the first intratracheal instillation of saline or BL and thereafter daily throughout the study for taurine + niacin + saline and taurine + niacin + BL groups. Hamsters received BL or saline in three consecutive doses at weekly intervals by intratracheal route. Twenty days after the last intratracheal instillation, the hamsters were sacrificed for various studies. RESULTS: Combined treatment with taurine and niacin suppressed BL-induced inflammation and almost completely abrogated pulmonary fibrosis in hamsters. Two independent studies showed that taurine and niacin in combination significantly reduced BL-induced increases in bronchoalveolar inflammatory cell counts, protein content, and acid phosphatase activity. By both light and electron microscopy, the lungs of hamsters treated with BL and taurine and niacin had much fewer inflammatory cells, less epithelial necrosis and collagen deposition than hamsters treated with BL alone. CONCLUSIONS: The results of this investigation suggest that combined treatment with taurine and niacin is effective against the development of lung fibrosis in the BL-hamster model and offers a novel therapeutic modality in the prevention of the fibrotic processes.

Animals↗
PubMed1992

Relationship of cytochrome P-450 activity to Clara cell cytotoxicity. III. Morphometric comparison of changes in the epithelial populations of terminal bronchioles and lobar bronchi in mice, hamsters, and rats after parenteral administration of naphthalene.

BACKGROUND: The purpose of this study was to define, in quantitative terms, epithelial alterations produced by the cytochrome P-450-activated Clara cell cytotoxicant, naphthalene, in lobar bronchi and terminal bronchioles of three species with differing sensitivity: mouse, rat, and hamster. EXPERIMENTAL DESIGN: Adult mice, hamsters, and rats were treated intraperitoneally with a single dose of naphthalene ranging from 0 mg/kg up to the approximate LD50. The animals were killed 24 hours postinjection and the changes in airway epithelium characterized by light microscopic morphometry. RESULTS: In mouse, bronchiolar epithelial thickness was significantly elevated by low, but not high, doses; ciliated cell number increased and Clara cell number decreased in a dose-dependent fashion. Vacuolated Clara cell number increased in all treated mice. In rat and hamster, bronchiolar epithelial thickness or cell number did not change. In mice, bronchial epithelial thickness was unchanged except at high doses, but both ciliated and Clara cell number was decreased. In bronchi of rats, epithelial thickness and numbers of nonciliated, ciliated, and basal cells were unchanged. In bronchi of hamsters, both ciliated and nonciliated cell number were decreased. CONCLUSIONS: (a) In mice, naphthalene-induced acute bronchiolar toxicity involves not only Clara cells, but also affects the purported nontarget cell type (ciliated cells). (b) In rats and hamsters, bronchiolar epithelium is insensitive to naphthalene injury. (c) In mice, injury to bronchi occurs at higher doses than in bronchioles and involves both ciliated and nonciliated cells. (d) In rats, bronchi are insensitive. (e) In hamsters, bronchi are more sensitive than bronchioles. This study emphasizes the variability of response by species, airway and epithelial cell type to cytochrome P-450-mediated pulmonary toxicants and the need for precise quantitative methods of defining both cytotoxic and metabolic events.

Animals↗
PubMed1991

Amelioration of bleomycin-induced pulmonary fibrosis in hamsters by combined treatment with taurine and niacin.

Interstitial pulmonary fibrosis induced by bleomycin (BL) involves the production of reactive oxygen species and the impairment of repair of damaged epithelial cells. We have shown previously that taurine or niacin treatment partially attenuates BL-induced lung fibrosis in hamsters and that the two agents probably act through different mechanisms. In the present investigation, we have demonstrated that taurine and niacin in combination provide nearly complete protection against BL-induced pulmonary fibrosis. Based on the findings of this investigation, it is suggested that combined treatment with taurine and niacin offers the potential for a novel pharmacological approach in the prevention of lung fibrosis in humans.

Administration, Oral↗
PubMed1991

A morphometric study of the lungs of different sized bats: correlations between structure and function of the chiropteran lung.

1. The lungs of four species of bats, Phyllostomus hastatus (PH, mean body mass, 98 g), Pteropus lylei (PL, 456 g), Pteropus alecto (PA, 667 g), and Pteropus poliocephalus (PP, 928 g) were analysed by morphometric methods. These data increase fivefold the range of body masses for which bat lung data are available, and allow more representative allometric equations to be formulated for bats. 2. Lung volume ranged from 4.9 cm3 for PH to 39 cm3 for PP. The volume density of the lung parenchyma (i.e. the volume proportion of the parenchyma in the lung) ranged from 94% in PP to 89% in PH. Of the components of the parenchyma, the alveoli composed 89% and the blood capillaries about 5%. 3. The surface area of the alveoli exceeded that of the blood-gas (tissue) barrier and that of the capillary endothelium whereas the surface area of the red blood cells as well as that of the capillary endothelium was greater than that of the tissue barrier. PH had the thinnest tissue barrier (0.1204 microns) and PP had the thickest (0.3033 microns). 4. The body mass specific volume of the lung, that of the volume of pulmonary capillary blood, the surface area of the blood-gas (tissue) barrier, the diffusing capacity of the tissue barrier, and the total morphometric pulmonary diffusing capacity in PH all substantially exceeded the corresponding values of the pteropid species (i.e. PL, PA and PP). This conforms with the smaller body mass and hence higher unit mass oxygen consumption of PH, a feature reflected in the functionally superior gas exchange performance of its lungs. 5. Morphometrically, the lungs of different species of bats exhibit remarkable differences which cannot always be correlated with body mass, mode of flight and phylogeny. Conclusive explanations of these pulmonary structural disparities in different species of bats must await additional physiological and flight biomechanical studies. 6. While the slope, the scaling factor (b), of the allometric equation fitted to bat lung volume data (b = 0.82) exceeds the value for flight VO2max (b = 0.70), those for the surface area of the blood-gas (tissue) barrier (b = 0.74), the pulmonary capillary blood volume (b = 0.74), and the total morphometric lung diffusing capacity for oxygen (b = 0.69) all correspond closely to the VO2max value. 7. Allometric comparisons of the morphometric pulmonary parameters of bats, birds and non-flying mammals reveal that superiority of the bat lung over that of the non-flying mammal.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Repeated episodes of C5a-induced neutrophil influx do not result in pulmonary fibrosis.

Multiple reactive oxygen species-induced epithelial injury by glucose, glucose oxidase, and lactoperoxidase instillation in the lung results in a progressive interstitial fibrosis. To test the hypothesis that multiple pulmonary inflammatory responses alone would not result in fibrosis, three sequential inflammatory reactions were produced at weekly intervals in hamster lungs via intratracheal instillation of human recombinant C5a. Numbers of neutrophils and total inflammatory cells in bronchoalveolar lavage (BALF) increased significantly at 24 h after each C5a treatment compared with saline controls. Neutrophils increased by 3-, 33-, and 34-fold compared with the corresponding controls at 24 h after the first, second, and third doses, respectively, but returned to control levels by six days postinstillation. LTB4 levels increased by 24% and 20% compared with the corresponding controls at 24 h after the first and second doses but were not different from controls at other times. Hydroxyproline levels in treated animals did not differ significantly from control levels throughout the study. Protein levels were significantly increased at 24 h after the second and third doses and six days after the third dose compared with the corresponding controls. Occasional foci of neutrophils in alveolar spaces were observed at 24 h after each dose, but they decreased in frequency after six days. No foci of neutrophils were observed six days after the final dose, although some epithelial degeneration was observed by transmission electron microscopy. Our results indicate that pulmonary inflammation resulting from repeated influx of neutrophils in response to multiple instillations of C5a in the lung does not cause sufficient injury to result in pulmonary fibrosis.

Animals↗
PubMed1991

Morphometric assessment of pulmonary toxicity in the rodent lung.

An overview of the epithelial and interstitial composition of rat respiratory airways shows complexity and variability. Airway epithelium varies in 1) different airway levels; 2) the types and ultrastructure of cells present; and 3) the abundance, type, and composition of stored secretory product. Unbiased sampling of airways is done using airway microdissection with a specific binary numbering system for airway generation. Vertical sections of selected airways are used to sample epithelium and interstitium. We determine the ratios of the volume of epithelial or interstitial cells to the total epithelial or interstitial volume (Vv). The surface of the epithelial basal lamina to the total epithelial or interstitial volume (Sv) is determined using point and intersection counting with a cycloid grid. Using the selector method on serial plastic sections, we determine the number of epithelial or interstitial cells per volume (Nv) of total epithelium or interstitium. We calculate the number of epithelial or interstitial cells per surface of epithelial basal lamina (Ns) by dividing Nv by Sv where the volumes are the same compartment. We calculate average cell volumes (v) for specific epithelial and interstitial cells by dividing the absolute nuclear volume by the ratio of the nucleus to cell volume (Vv). By multiplying the average cell volume (v) by the ratio of organellar volume to cell volume (Vv), we calculate the average organellar volume per cell. These unbiased stereological approaches are critical in a quantitative evaluation of toxicological injury of rat tracheobronchial airways.

Administration, Inhalation↗