银杏叶提取物对大鼠糖尿病性白内障防治作用的研究

目的探讨银杏叶提取物(extract of ginkgo biloba,GBE)对大鼠糖尿病性白内障(diabetic cataract,DC)的防治作用及可能机制。方法 60只♂SD大鼠随机分为正常对照组、DC模型组、GBE低、中、高剂量组和苄达赖氨酸组。给药12周后,裂隙灯观察大鼠晶状体变化并对其混浊度进行分级;可见光分光光度法测定晶状体中过氧化氢酶(cata-lase,CAT)、谷胱甘肽(glutathione,GSH)和总超氧化物歧化酶(total superoxide dismutase,T-SOD)水平;ELISA法测定糖基化终末产物(advanced glycosylation end products,AGEs)含量;Western blot法测定醛糖还原酶(aldose reductase,AR)相对表达水平。结果 DC组大鼠晶状体明显混浊;GBE中高剂量组较DC组大鼠晶状体混浊程度减轻。DC组大鼠与NS组相比,晶状体中CAT、T-SOD活性降低,GSH含量减少(P<0.01);中高剂量GBE可提高CAT、T-SOD活性及GSH含量(P<0.05或P<0.01)。与NS组相比,DC组大鼠晶状体中的AGEs含量及AR表达明显升高(P<0.01);中高剂量GBE治疗后,AGEs含量与AR表达明显下调(P<0.01)。结论 GBE可能通过增强抗氧化能力、抑制AGEs产生及AR表达,从而减轻大鼠晶状体混浊度,对DC的防治具有积极作用。

Preventive effects of Ginkgo biloba extract on rat diabetic cataract

Aim To observe the preventive and therapeutic effects of Ginkgo biloba extract(GBE) on diabetic cataract(DC) in rats and the possible molecular mechanisms.Methods Diabetes mellitus model was induced by streptozotocin in rats and the diabetes mellitus rats were divided into 6 groups: normal control group;DC group;low dose of GBE group;moderate dose of GBE group;high dose of GBE group;and BendazacLysine treated group(BDL,BendazacLysine treated at dose of 200 mg·kg-1).Every group was treated for 12 weeks.After treatment,samples were collected.The changes of body weight were monitored every week;eyes of rats were examined with a slit lamp biomicroscope on dilated pupils.Initiation and progression of lenticular opacity were assessed according to the Azuma system;the levels of antioxidative indexes including CAT,GSH and T-SOD were assayed by visible spectrophotometry;advanced glycosylation end products(AGEs) were represented by the method of ELISA;the expression of the aldose reductase(AR) was detected by Western blot analysis.Results The control rats retained clear lenses throughout.All of the DC rats developed cataracts and their lens progressed to opacity.Compared with the DC rats,the degree of lens opacification of GBE treated groups was greatly reduced.The activities of the CAT,T-SOD and the level of GSH were decreased significantly in DC groups compared with those in NS groups(P<0.01),but the levels of these indexes were increased significantly in GM and GH groups compared with those in DC group(P<0.01 or P<0.05).The AGEs level and AR proteins were increased in DC group compared with NS group(P<0.01).After treatment with GBE,the AGEs level and AR expressions were decreased significantly compared with those in DC group(P<0.01).Conclusion GBE has effects of anti-oxidation,AR inhibition,reducing the AGEs level on DC rats.Therefore,GBE has preventive and protective effects on several pharmacological targets in the progress of DC and is a potential drug for the prevention of DC.