桑枝多糖对糖尿病肾病小鼠肾皮质氧化应激作用的影响

The anti-oxidative effect of Ramulus mori polysaccharides on diabetic nephropathy mice

目的研究桑枝多糖对链脲佐菌素(STZ)诱导糖尿病肾病小鼠肾皮质氧化应激作用的影响。方法 STZ(120 mg·kg^(-1))尾静脉注射诱导糖尿病小鼠模型,并随机分为:模型组,缬沙坦组(20 mg·kg^(-1)),桑枝多糖0.3、0.6、1.2 g·kg^(-1)组,另设空白组,连续灌胃给药90 d。于d 45将各组小鼠给药后置代谢笼中收集24 h尿液,记录排尿量,检测24 h尿微量白蛋白含量。90 d后处死小鼠,通过对肾脏HE染色观察肾脏病理学变化;全自动生化分析仪测定血清中尿素氮(BUN)、肌酐(Cr)的含量;试剂盒测定大鼠肾皮质中锰超氧化物歧化酶(Mn-SOD)、氧化氢酶(CAT)、线粒体呼吸链复合物Ⅰ、Ⅲ的活性和丙二醛(MDA)含量;ELISA法检测肾皮质ROS的含量;蛋白免疫印迹法检测肾皮质中SIRT1、FOXO1、NF-κB的蛋白表达。结果桑枝多糖组的肾皮质病变得到缓解,较模型组的血糖有所下降,并明显降低尿微量白蛋白含量、尿量及血清中Cr、BUN(P<0.05),肾皮质Mn-SOD、CAT、线粒体呼吸链复合物Ⅰ、Ⅲ活性有所升高,ROS、MDA含量下降(P<0.05),上调SIRT1、FOXO1的蛋白水平以及下调NF-κB的蛋白水平(P<0.05)。结论桑枝多糖对糖尿病小鼠肾脏损害有一定的保护作用,机制可能与其通过增加肾皮质中SIRT1、FOXO1的蛋白表达,增强组织的抗氧化能力有关。

Aim To investigate the influence of Ramu-lus mori polysaccharides （ RMP） on blood glucose and anti-oxidative effect in streptozotocin （ STZ ）-induced diabetic mice .Methods Diabetic mice were induced by intraperitoneal injection with 120 mg？ kg -1 STZ and were randomly divided into the following 5 groups with 20 animals per group： model group , valsartan group （ 20 mg？ kg -1 ） , low-, medium-, high-dose （0.3,0.6,1.2 g·kg^-1 ） of RMP groups.Other 20 normal mice were treated as normal control group .The mice were administered orally for 90 d.On 45 d of ad-ministration , the 24 h urine was collected through met-abolic cages for urine protein detection .Pathological changes of kidney tissues were observed through HE staining .The serum levels of urea nitrogen （ BUN） and creatinine （ Cr ） were detected by automatic biochemical analyzer; and the manganese superoxide dismutase （Mn-SOD）, catalase（CAT）, malonaldehyde（MDA） and mitochondrial respiratory chain complex Ⅰ,Ⅲac-tivity of kidney tissues were also determined .ELISA method was used to detect ROS content in renal cortex . The SIRT1 , FOXO1 and NF-κB protein expressions were analyzed by Western blot .Results Compared with model group, the FBG, microalbuminuria, BUN and Cr were decreased by RMP medication （ P 〈0.05）.The activities of Mn-SOD, CAT and mitochon-drial respiratory chain complex Ⅰ,Ⅲ in RMP groups were enhanced , while MDA and ROS levels were re-duced. Moreover, the expressions of SIRT1 and FOXO1 were up-regulated by RMP , the expression of NF-κB was down-regulated （ P〈0.05） .Conclusion RMP exerts renal protective effect through up-regula-ting the expressions of SIRT1 and FOXO1 in renal cor-tex , which may relate to the improvement of anti-oxida-tive capability .