الفهرس 
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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.