The effeCT Of hypeRChOlesTeROlemIa ON The RaT paROTID salIvaRy GlaNDs (hIsTOpaThOlOGICal aND ImmUNOhIsTOChemICal sTUDy)

. AbstrAct Hypercholesterolemia is a common risk problem. It is a well-known aggravating factor in the pathogenesis of many diseases so that, the present study was conducted to induce hypercholesterolemia in rats by long-term high-cholesterol diet administration then investigate the histopathological and immunohistochemical changes in parotid salivary glands of these animals and discuss their potential significances in understanding the mechanism by which hypercholesterolemia had adversely affected the tissues. Thirty male albino rats (150 ±10 grams) were divided equally into control and experimental groups. The rats of the experimental group received hypercholesterolmic diet containing 1% cholesterol for 3 consecutive months, while the rats of control group were kept on normal diet. At the end of the experimental period, all rats were sacrificed. The parotid salivary glands were dissected out and prepared for histopathological and immunohistochemical examinations. Histopathological examination revealed severely atrophied serous acini and massive fibrosis formed of thick collagen fibers, thick walled lymphatics and numerous dilated blood vessels. The excretory ducts were degenerated with retained secretion. There were numerous intra and intercellular vacuoles. There were also numerous large vacuoles as well as severe haemorrhage in the connective tissue stroma. Some specimens revealed complete replacement of the salivary glands lobes by numerous large empty spaces. Immunohistochemical examination revealed intense positive immunoreactivity for Fas in the acinar and duct cells. Whereas, both of the acinar and duct cells showed negative p53 immunoreactivity. In conclusion, the major manifestations of hypercholesterolemia inducing salivary glands injury are apoptosis, fibrosis, fatty degeneration, lipid accumulation and microcirculatory disturbances.