火绒草对2型糖尿病大鼠腺垂体内NPY和leptin表达的影响

Effects of Leontopodium alpinum pretreatment on the expression of NPY and leptin in anterior pituitary in rats with type 2 diabetes mellitus

目的:观察火绒草对2型糖尿病(T2DM)大鼠腺垂体内神经肽Y(NPY)及leptin表达的影响。方法:将24只SD大鼠随机分为3组,即正常组、模型组和火绒草预处理组。模型组、火绒草预处理组大鼠的建立用链脲佐菌素(STZ)诱导的T2DM大鼠模型,火绒草预处理组于注射STZ前给予火绒草灌胃35 d。大鼠血糖采用酶法检测,大鼠腺垂体内NPY和leptin蛋白及mRNA的表达采用免疫组织化学染色和RT-PCR。结果:火绒草预处理组大鼠血糖明显低于模型组(P<0.01)。免疫组织化学染色显示,NPY和leptin免疫阳性产物均为棕黄色颗粒状,免疫阳性细胞均为腺垂体内嗜色细胞,NPY主要位于细胞质,leptin主要位于细胞核。与模型组大鼠相比,火绒草预处理组大鼠NPY和leptin蛋白的表达明显降低(P<0.01)。RT-PCR结果表明,火绒草预处理组大鼠NPY和leptin mRNA的表达明显低于模型组(P<0.01)。结论:火绒草预处理可下调STZ诱导的大鼠腺垂体内NPY和leptin的高表达,对T2DM腺垂体损伤具有明显保护作用。

Objective： To investigate the effects of Leontopodium alpinum pretreatment on the expressions of neuropeptide Y,NPY） and leptin in the anterior pituitary for rats with STZ-induced type 2 diabetes mellitus（ T2DM）. Methods：Twenty-four SD rats were randomly divided into 3 groups： control group,model group and Leontopodium alpinum pretreatment group. The modal rats were established by intraperitoneally injection of streptozotocin（ STZ） in model group and Leontopodium alpinum pretreatment group. The rats in Leontopodium alpinum pretreatment group were lavaged with Leontopodium alpinum for 35 days before injecting STZ. The enzymic method was used to measure the blood glucose. Immunohistochemical staining and RT-PCR were used to observe the expression of NPY and leptin protein and mRNA,Yespectively in anterior pituitary. Results： The blood glucose of sericine pretreatment group rats were significantly lower than that of model group（ P 〈 0. 01）. Immunohistochemical staining showed that NPY and leptin immunoreactive products were brown granular,and expressed in chromophil cells of the anterior pituitary. NPY was located in the cytoplasm,while leptin was mainly located in nucleus. Compared with model rats,the protein expressions of NPY and leptin in the anterior pituitary of the rats in Leontopodium alpinum pretreatment group were decreased obviously（ P 〈 0. 01）. RT-PCR results showed that the NPY and leptin mRNA expression in Leontopodium alpinum pretreatment group rats were significantly lower than that in the model group（ P 〈 0. 01）. Conclusion： The results show that Leontopodium alpinum pretreatment down-regu-late the high expression of NPY and leptin protein and mRNA in anterior pituitary STZ-induced rats,therefore Leontopodium alpinum has obviously protective effects on anterior pituitary injury for rats with the T2 DM.