الفهرس | Only 14 pages are availabe for public view |
Abstract The present study was planned to evaluate the effect of green tea extract on the experimentally induced lung fibrosis in adult albino rat. Thirty adult albino rats of both sex weighted 200 gram were utilized in this study. They were classified into four groups: group I (control group) consisted of ten rats, was divided into two subgroups five rats for each one, subgroup Ia rats were fed on standard diet without any treatment and subgroup Ib rats were received normal saline 0.9% intraperitonally as a solvent of bleomycin. Group II (green tea extract group) consisted of five rats, they were received green tea extract orally by gastric tube. group III (lung fibrosis induction group) consisted of five rats, they were received bleomycin (15 mg/kg/d) 3 times a week for 4 weeks intraperitonally to induce a model of lung fibrosis. group IV (Bleomycin and green tea extract group) consisted of ten rats, was subdivided into two subgroups, five rats for each one. Subgroup IVa,its animal received green tea extract for two weeks before the start of bleomycin injection then continued with bleomycin for addition of four weeks. Subgroup IVb, its animal received green tea extract with bleomycin for a total period of four weeks then continued with green tea extract only for addition of two weeks after stoppage of bleomycin. Rats from all above mentioned groups were anaesthetized lightly by diethyl ether inhalation then sacrificed after the recommended duration of each group. Lungs of each animal were carefully dissected and one lung from each different group undergo genetic study by agarose gel electrophoresis to detect DNA fragmentation and other lungs were removed for histological paraffin sections to undergo light microscope study, histologically by hematoxylin and eosin for routine study. Mallory trichrome stain for detection of collagen deposition. Also immunohistochemical studies with inducible nitric oxide synthase (INOS) to detect oxidative stress and tumor necrosis factor α (TNFα) to detect proinflammatory cytokines respond. The morphometric measurements were done by the image analyzer for calculating percentage of immunoreactivity positive cells in INOS and TNFα as well as percentage of surface area of collagen fibers deposition in interalveolar septum, pulmonary perivascular area and peribronchiolar area then statistical analysis was done. Results: group I (control group) and group II (green tea extract group) showed similar histological results like normal lung. group III (lung fibrosis induction group) showed extensive damage with loss of normal alveolar architecture. Most of the lung section showed diffuse inflammatory cellular infiltration resulting in massive consolidation, alveolar collapse. Other lung section showed ruptured interalveolar septa with the formation of large irregular emphysematous air spaces, area of hemorrhage, hemosiderosis and hyaline degeneration. Pulmonary arterioles appeared markedly thickened and congested with partial destruction of their linning endothelium. Also bronchioles appeared with markedly thickened wall, partial destruction, hyperplesia and vacuolation of their linning epithelium. Excess mucous secretion in their lumen. By mallory trichrome stain, revealed extensive collagen fibers deposition in interalveolar septum, pulmonary perivascular and peribronchiolar areas. By immunohistochemically study, showing strong positive immunoreactivity in both INOS and TNF α. Genetically study by agerose gel electrophoresis, detected that massive DNA fragmentation. Co-administration of green tea extract and bleomycin showed greatly histopathological as marked decreased inflammatory cellular infiltration. Area of hemorrhage, hemosiderosis, vacuolation and emphysematous changes were rare detected, pulmonary arterioles and bronchioles were nearly normal also decreased collagen fibers deposition in interalveolar septa, peribronchiolar and perivascular areas. Immunohistochemical study of INOS and TNFα greatly decreased as compared to lung fibrosis induction group, morphometrical and statistical studies confirmed our result. Genetical study showed decreased DNA fragmentation in group IV. The improvements were nearly normal when green tea extract used early before the lung fibrosis induction as in subgroup IVa. |