银杏叶提取物对实验性糖尿病大鼠脑组织的保护作用

目的: 研究银杏叶提取物(extractofGinkgobiloba,EGB)对糖尿病大鼠脑的保护作用及其机制。方法: 选用雄性SD大鼠,随机分为糖尿病组、银杏叶组和正常对照组。应用链脲佐菌素(STZ)诱导制备大鼠糖尿病模型。银杏叶组腹腔注射银杏叶提取物注射液,其余两组给予同容积的生理盐水,用药5周后,测定脑组织内皮素(ET)、丙二醛(MDA)、NO产物NO2-NO3-的含量及超氧化物歧化酶(SOD)、一氧化氮合酶(NOS)的活性,以及血清中的血糖、胰岛素、ET水平,并作光镜及透射电镜观察。结果: 糖尿病脑组织光镜下可见脑水肿、脑软化、神经细胞变性、白质脱髓鞘,透射电镜下可见神经元及神经胶质细胞内线粒体肿胀、嵴变短、神经纤维脱髓鞘、血脑屏障受损。EGB治疗后光镜、电镜下的病变明显减轻。与糖尿病组相比,银杏叶组大鼠血糖、血浆ET水平下降、胰岛素水平升高,脑组织内SOD活性明显升高,NOS活性、ET、MDA、NO2-NO3-的含量明显下降。结论: EGB可能通过抗脂质过氧化及降低NO、ET水平,对糖尿病大鼠脑组织产生保护作用。

Protective effects of extract of Ginkgo biloba on brain tissues in experimental diabetic rats

AIM: To study the protective effects of the extract of Ginkgo biloba (EGB) on brain tissues in experimental diabetic rats and explore its possible mechanisms.METHODS: Thirty male Sprague-Dauley rats were divided into three groups:normal control group, diabetic group and EGB-treated group.Strepozotocin were injected intraperitoneally on the later two groups to induce diabetes, EGB-treated group was injected intraperitoneally with EGB, and the others were treated with normal saline at the same volume.After five weeks, the content of endothelin (ET), malondial dehyde (MDA), NO2-NO3-, and the activity of superoxide dismutase (SOD), nitric oxide synthase (NOS) were determined in brain homogenate, and the level of blood glucose, insulin and ET were measured respectively.In addition, the morphologic changes of the brain tissue were studied by light microscopy and electron microscopy, respectively.RESULTS: In diabetic group, there were degeneration of neuron, brain edema, softened focus and demyelination in the white matter of brain by light microcopy.There were expansion of mitochondria of neuron and gliocyte, the shortened of crista, demyelination of neurofiber and injury of bloodbrain-barrier by the electron microscopy.After treated with EGB, the pathological changes decreased in brain under light microcopy and electron microcopy.Compared with diabetic rats, the activity of SOD and the level of serum insulin increased, while the level of blood ET, the activity of NOS, the content of ET, MDA, NO2-NO3-decreased in EGB-treated rats (P <0.05).CONCLUSION: EGB can protect diabetic brain by anti-lipid peroxidation and decrease the level of NO and ET.