A Histological Assessment of the Possible Protective effect Of Green Tea On age-induced hepatic stellate cell activation in rat

Background: it is now well documented that aging is associated with many histological changes in the liver; however, the effect of old age on hepatic stellate cells (HSCs) has not been well described Moreover, the protective effect of green tea (GT) extract was a subject of interest to study in livers of male albino rats. Aim of the work: the current study was carried by immunohistochemical and electron microscopic means to show the fibrotic changes that may occur in normal rat liver in relation to age; and to correlate these possible changes with the activation of HSCs. Furthermore, the probable protective antifibrotic role of GT administration in old rats was examined. Materials and methods: The current study was carried on 15 apparently healthy male albino rats that were classified equally into three groups: Group I: 12- month old rats. Group II: 30-months old rats. Group III: 26 months old rats that received GT preparation daily orally at a dose of (100 mg/kg) for 4months. Liver sections were subjected to both light (H E, Masson s trichrome and anti-glial fibrillary acidic protein (GFAP) immunohistochemical staining) and electron microscopic studies. Morphometric studies included area% of collagen fibers and optical density of GFAP immunoreactive HSCs. Results: H E- stained sections of group III revealed obvious cytoplasmic vacuolations of hepatocytes. However, the mean area % of collagen fibers and the mean optical density of GFAP immunopositive HSC were significantly increased in group II when compared with the other two groups. Furthermore, most GFAP immunopositive HSCs lost their cytoplasmic, processes in group II and this observation was strengthened by the electron microscopic results which revealed a decrease in the size of lipid droplets and more developed rough endoplasmic reticulum in old age. This might reflect activation of HSCs to myofibroblasts. Conclusion: Although GT attenuated the fibrotic changes noticed in old age, it strikingly caused hepatotoxicity which may arouse certain limitations to its wide spread use.