红芪多糖对糖尿病周围神经病小鼠的神经组织纤维化的改善作用及其机制

Improvement and its mechanism of Hedysarum polybotrys polysaccharide on fibrosis of nerve tissue in diabetic peripheral neuropathy mice

目的观察红芪多糖(HPS)对糖尿病周围神经病(DPN)小鼠(即ob/ob小鼠)的神经组织Kelch样环氧氯丙烷相关蛋白(Keap1)与核因子E2相关因子2(Nrf2)表达的影响。方法按照体重将DPN小鼠随机分为5组:糖尿病模型组、对照组(α-硫辛酸4 mg·kg^(-1)·d^(-1))和高、中、低3个剂量实验组(HPS:200,100,50 mg·kg^(-1)·d^(-1)),每组10只。同品系非糖尿病C57BL/6野生型小鼠10只作为正常组;模型组和正常组给予等剂量蒸馏水5 m L·kg^(-1)·d^(-1),均每日1次,连续8周。以免疫印迹法和RT-PCR法分别检测神经组织中Keap1、Nrf2的蛋白和基因表达水平。结果给药8周后,正常组、模型组、对照组和中、高2个剂量实验组的Keap1蛋白表达灰度值分别为0. 59±0. 07,1. 10±0. 08,0. 63±0. 03,0. 81±0. 13和0. 73±0. 15;这5组的Nrf2蛋白表达灰度值分别为0. 91±0. 01,0. 51±0. 07,0. 88±0. 05,0. 76±0. 17和0. 87±0. 02。模型组与正常组比较,Keap1表达明显升高而Nrf2表达明显降低,差异均有统计学意义(均P <0. 01);中、高2个剂量实验组和对照组与模型组比较,Keap1表达明显降低而Nrf2表达明显升高,差异均有统计学意义(均P <0. 01)。基因结果的趋势与蛋白一致。结论 HPS可减轻模型小鼠糖尿病周围神经病神经组织纤维化程度,其作用可能与调控Keap1/Nrf2信号通路,使机体内抗氧化酶活性增加有关,从而减缓小鼠的神经纤维化速度。

Objective To observe the effect of Hedysarum polybotrys polysaccharide(HPS)on the expressions of Kelch-like epichlorohydrin-associated protein 1(Keap1)and nuclear factor 2(Nrf2)in neural tissue of diabetic peripheral neuropathy(DPN)mice.Methods According to body weight,ob/ob mice(DPN mice)were randomly divided into five groups:diabetic model group,control group(α-lipoic acid,4 mg·kg-1·d-1)and high,medium and low dose experimental groups(HPS:200,100,50 mg·kg-1·d-1),with 10 mice in each group.Ten wild-type C57 BL/6 mice of the same strain of non-diabetes mellitus were served as normal group.The model group and the normal group were given 5 m L·kg-1·d-1 distilled water at the same dose once a day for 8 weeks.The protein and gene expression levels of Keap1 and Nrf2 in nerve tissue were detected by Western blotting and RT-PCR,respectively.Results After 8 weeks of administration,the gray values of Keap1 protein expression in normal group,model group,control group and high,medium dose experimental groups were 0.59±0.07,1.10±0.08,0.63±0.03,0.81±0.13 and 0.73±0.15,respectively.The gray values of Nrf2 protein expression in these five groups were 0.91±0.01,0.51±0.07,0.88±0.05,0.76±0.17 and 0.87±0.02.Compared with the normal group,the expressions of Keap1 and Nrf2 in the model group increased and decreased significantly,respectively,and the differences were statistically significant(all P<0.01).Compared with the model group,the expression of Keap1 decreased significantly and the expression of Nrf2 increased significantly in the middle and high dose experimental groups(all P<0.01).The trend of gene results is consistent with that of protein.Conclusion HPS can alleviate the degree of fibrosis of nerve tissue in DPN mice,which may be related to the regulation of Keap1/Nrf2 signaling pathway and the increase of antioxidant enzyme activity in vivo,thus slowing down the rate of nerve fibrosis in mice.