银杏叶提取物对老年大鼠肝脏的保护作用

目的了解银杏叶提取物对老年大鼠肝脏的作用。方法3月龄和20月龄大鼠以银杏叶提取物（生理盐水）灌胃3月，观察肝脏病理学、血清酶学、肝组织中金属蛋白酶组织抑制因子-1（tissue inhibitor-1 of metalloproteinase，TIMP—1）表达、丙二酰二醛（malondialdehyde，MDA）、超氧化物歧化酶（superoxi dedismutase，SOD）和谷胱甘肽过氧化物酶（glutathione peroxidase，GPx）含量、增殖细胞核抗原（proliferating cell nuclear antigen，PCNA）表达的变化。结果老年大鼠存在轻度肝纤维化，与青年组大鼠相比较，老年大鼠肝细胞数目明显减少（P〈0．01），脂褐素数量明显增加（P〈0．01），肝组织中MDA水平升高而SOD和GPx活性降低（P〈0．01或P〈0．05），TIMP—1表达增强，PCNA表达减弱（P〈0．01）。银杏叶提取物可使老年大鼠肝脏病理学改善（P〈0．01），脂褐素减少（P〈0．01），肝组织中MDA水平降低（P〈0．05）而GPx活性升高（P〈0．01），SOD活性略有升高（P〈0．05），TIMP—1表达降低，使PCNA表达增强（P〈0．01）。各组大鼠肝功能无明显变化（P〈0．05）。结论银杏叶提取物对老年大鼠肝脏有明显的保护作用，其机制可能与银杏叶提取物抗氧化、增强老年肝脏抗氧化能力、抑制TIMP—1表达、促进PCNA表达有关。

PROTECTIVE EFFECT OF GINKGO BILOBA EXTRACT ON LIVERS IN AGING RATS

ObjectiveTo assess the effection of Ginkgo biloba extract(GbE) on livers of aging rats.MethodsBoth 2-month-old rats and 20-month-old rats treated with GbE/saline for 3 months.Liver tissue samples from 5-month-old rats treated with saline(Y group) and 23-month-old rats treated with GbE(E group) or saline(N group) were used for histopathological examinations(H&E and Masson staining) and determination of expression of tissue inhibitor-1 of metalloproteinase(TIMP-1) and the level of malondialdehyde(MDA),glutathione peroxidase(GPx) and superoxide dismutase(SOD).Blood samples were collected for determination of alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL) and albumin.The expression of proliferating cell nuclear antigen(PCNA) and lipofuscin in liver samples was also examined.ResultsMicroscopic studies with Masson staining revealed mild liver fibrosis in aging rats while the livers of aging rats receiving GbE showed decreasing in fibrosis(P<(0.01)).Compared with Y group,the level of liver MDA and lipofuscin increased while the activity of GPx and SOD decreased in N group(P<(0.01) or P<(0.05)).At the same time,the expression of PCNA decreased(P<(0.01)) while the expression of TIMP-1 increased in N group.Treated with GbE,the expression of TIMP-1 and the level of liver MDA and lipofuscin decreased but the activty of GPx and the expression of PCNA increased in E group(P<(0.01) or P<(0.05)).There was no different of liver function between three groups(P>(0.05)).ConclusionGbE has protective effect on aging liver.The mechanisms possibly contribute to its action of antioxidant activity and its effect of inhibiting the expression of TIMP-1 and promoting the expression of PCNA.