基于Nrf2/HO-1通路探究虎杖苷对妊娠期糖尿病大鼠的治疗效果及作用机制

Exploring the therapeutic effects and action mechanism of polydatin on gestational diabetes mellitus rats based on Nrf2/HO-1 pathway

关键词:  虎杖苷  核转录因子E2相关因子2/血红素加氧酶-1  妊娠期糖尿病  作用机制

Key words:  polydatin  Nrf2/HO-1  gestational diabetes mellitus  action mechanism

摘要:

[目的] 探究虎杖苷（PD）对妊娠期糖尿病（GDM）大鼠的治疗效果及作用机制。[方法] 高脂高糖喂养雌性SD大鼠8周，雌雄同笼制备孕鼠84只，随机分为7组（12只/组）：空白组、模型组、PD低、中、高剂量组（30、75、150 mg/kg的PD）、阳性对照组（200 mg/kg盐酸二甲双胍）、抑制剂组[150 mg/kg的PD+30 mg/kg的核转录因子E2相关因子2（Nrf2）/血红素加氧酶-1（HO-1）通路抑制剂ML385]，除空白组外，其余各组在妊娠5 d后，腹腔注射链脲佐菌素（35 mg/kg）复制GDM大鼠模型。测量各组孕鼠体质量及空腹血糖（FBG）；酶联免疫吸附（ELISA）法测定大鼠空腹胰岛素（FINS）、白细胞介素（IL）-6、IL-1β、肿瘤坏死因子（TNF）-α水平，计算胰岛素抵抗指数（HOMA-IR）、胰岛β细胞功能指数（HOMA-β）、胰岛素敏感指数（ISI）；全自动生化分析仪分析大鼠血清中血脂水平；苏木精-伊红（HE）染色观察大鼠胰腺组织损伤；蛋白免疫印迹（Western Blot）法检测各组大鼠胰腺组织中Nrf2/HO-1信号通路蛋白表达。[结果] 与空白组比较，模型组大鼠体质量、FBG、FINS、HOMA-IR、IL-6、IL-1β、TNF-α水平、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、游离脂肪酸（FFA）含量升高，ISI、HOMA-β、高密度脂蛋白胆固醇（HDL-C）含量、胰岛数量、Nrf2、HO-1蛋白表达水平降低（P＜0.05）；与模型组比较，PD低、中、高剂量组大鼠体质量、FBG、FINS、HOMA-IR、IL-6、IL-1β、TNF-α水平、TC、TG、LDL-C、FFA含量降低，ISI、HOMA-β、HDL-C含量、胰岛数量、Nrf2、HO-1蛋白表达水平升高（P＜0.05）；与阳性对照组比较，PD高剂量组大鼠上述指标差异均无统计学意义（P＞0.05），提示与阳性对照药物疗效相当；Nrf2/HO-1通路抑制剂ML385可以逆转高剂量PD对GDM大鼠的保护作用（P＜0.05）。[结论] PD通过降低血糖、血脂和炎症反应来改善GDM，其作用机制可能与激活Nrf2/HO-1信号通路有关。

Abstract:

[Objective] To explore the therapeutic effect and action mechanism of polydatin（PD） on gestational diabetes mellitus（GDM） rats. [Methods] Female SD rats were fed with high fat and high sugar for 8 weeks，and 84 pregnant rats were prepared in the same cage. They were randomly grouped into 7 groups（12 rats/group）：control group，Model group，PD low，medium，and high dosage groups（30，75，150 mg/kg），positive control group（200 mg/kg metformin hydrochloride），and inhibitor group[150 mg/kg PD+30 mg/kg nuclear factor erythroid-2 related factor 2（Nrf2）/heme oxygenase 1（HO-1） pathway inhibitor ML385]. Except for the control group，the other groups were intraperitoneally injected with streptozotocin（35 mg/kg） to replicate the GDM rat model after 5 days of pregnancy. The body mass and fasting blood glucose（FBG） of pregnant rats in each group were measured；the levels of fasting insulin（FINS），interleukin（IL）-6，IL-1β and tumor necrosis factor（TNF）-α were measured by ELISA，the homeostasis model assessment-IR（HOMA-IR），islet β cell function index（HOMA-β） and insulin sensitive index（ISI） were calculated；the levels of serum lipids in rats were analyzed by automatic biochemical analyzer；HE staining was used to observe the damage of pancreatic tissue in rats；Western Blot was applied to detect the expression of Nrf2 and HO-1 signal pathway proteins in the pancreas of rats in each group. [Results] Compared with the control group，the body mass，the levels of FBG，FINS，HOMA-IR，IL-6，IL-1β，TNF-α，the contents of total cholesterol（TC），triglyceride（TG），low-density lipoprotein cholesterol（LDL-C），free fat acid（FFA） in the model group were obviously increased，the contents of ISI，HOMA-β，high-density lipoprotein cholesterol（HDL-C），the number of islets，the expression of Nrf2 and HO-1 proteins were obviously decreased（P＜0.05）；compared with the model group，the body mass，the levels of FBG，FINS，HOMA-IR，IL-6，IL-1β，TNF-α，the contents of TC，TG，LDL-C，FFA in the low，middle and high dose PD groups were obviously decreased，the contents of ISI，HOMA-β，HDL-C，the number of islets，the expression of Nrf2 and HO-1 proteins were obviously increased（P＜0.05）；compared with the positive control group，there was no obvious difference in the above indexes in the high-dose PD group（P＞0.05）；Nrf2/HO-1 pathway inhibitor ML385 could reverse the protective effect of high-dose PD on GDM rats（P＜0.05）. [Conclusion] PD improves GDM by reducing blood glucose，blood lipid and inflammatory response. The mechanism may be related to the activation of Nrf2/HO-1 signaling pathway.