基于糖基化终末产物受体(receptor for advanced glycation end products，RAGE)/酪氨酸激酶 1(janus activated kinase 1，JAK1)/信号转导和转录激活因子3(signal transduction and activator of transcription 3，STAT3)信号通路探讨红景天苷对糖尿病肾病(diabetic nephropathy，DN)小鼠肾损伤的保护作用。采用高糖高脂饮食联合腹腔注射链脲佐菌素(streptozotocin，STZ)建立小鼠DN模型，随机分为正常组、模型组、红景天苷低剂量(20 mg·kg-1)组、红景天苷高剂量(100 mg·kg-1)组、二甲双胍(140 mg·kg-1)组，每组12只。造模成功后每日灌胃相应药物或溶剂1次，持续10周，每2周测定体质量、日饮水量，检测空腹血糖(fasting blood glucose，FBG)。末次给药结束后，进行口服糖耐量测试，收集24 h尿液、血清及肾组织样本。采用生化法检测 24 h 尿蛋白(24 hours urinary total protein，24 h-UTP)，血清肌酐(serum creatinine，Scr)、尿素氮(blood urea nitrogen，BUN)、甘油三酯(triglyceride，TG)、总胆固醇(total cholesterol，TC)、低密度脂蛋白胆固醇(low density lipoprotein cholesterol，LDL-C)、高密度脂蛋白胆固醇(high density lipoprotein cholesterol，HDL-C)水平;过碘酸雪夫(periodic acid-Schiff，PAS)染色观察肾组织病理形态变化;免疫组织化学染色检测肾脏α-平滑肌肌动蛋白(α-smooth muscle actin，α-SMA)、波形蛋白(vimentin)、糖基化终末产物(advanced glycation end products，AGEs)表达;试剂盒检测肾组织超氧化物歧化酶(superoxide dismutase，SOD)、过氧化氢酶(catalase，CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase，GSH-PX)活力以及丙二醛(malondialdehyde，MDA)水平;酶联免疫吸附测定法(enzyme-linked immunosorbent assay，ELISA)检测血清 AGEs、羧乙基赖氨酸(carboxyethyllysine，CEL)、羧甲基赖氨酸(carboxymethyllysine，CML)水平;蛋白免疫印迹法(Western blot)检测肾组织RAGE蛋白表达以及JAK1、STAT3蛋白的磷酸化水平。结果显示，与正常组比较，模型组小鼠FBG，血糖曲线下面积(area under the curve of glucose，AUCG)，饮水量，肾脏指数，24 h-UTP，肾小管损伤评分，肾小球细胞外基质占比，血清中Scr、BUN、TG、LDL-C、AGEs、CEL、CML水平，肾组织中MDA含量，α-SMA、vimentin、AGEs、RAGE蛋白表达及JAK1、STAT3蛋白的磷酸化水平显著增加(P＜0。01);血清HDL-C水平，肾组织SOD、CAT、GSH-PX活力显著降低(P＜0。01)。与模型组比较，红景天苷高剂量组小鼠上述指标变化均显著逆转(P＜0。05或P＜0。01)。该研究表明，红景天苷可通过抑制AGEs介导的RAGE/JAK1/STAT3信号轴活性减轻氧化应激反应和肾脏纤维化，发挥治疗DN的作用。
Protective effect of salidroside on renal damage in diabetic nephropathy mice by regulating RAGE/JAK1/STAT signaling pathway
This study aims to investigate the protective effect of salidroside(SAL)on renal damage in diabetic nephropathy(DN)mice based on the receptor for advanced glycation end products/janus activated kinase 1/signal transduction and activator of transcription 3(RAGE/JAK1/STAT3)signaling pathway.The mouse DN model was established by high-fat/high-sucrose diets combined with intraperitoneal injection of streptozocin(STZ).Mice were randomly divided into normal group,model group,low-dose SAL group(20 mg·kg-1),high-dose SAL group(100 mg·kg-1),and metformin group(140 mg·kg-1),with 12 mice in each group.After establishing the DN model,mice were given drugs or solvent intragastrically,once a day for consecutive 10 weeks.Body weight,daily water intake,and fasting blood glucose(FBG)were measured every two weeks.After the last dose,the glucose tolerance test was performed,and the samples of 24-hour urine,serum,and kidney tissue were collected.The levels of 24 hours urinary total protein(24 h-UTP),serum creatinine(Scr),blood urea nitrogen(BUN),triglyceride(TG),total cholesterol(TC),low density lipoprotein cholesterol(LDL-C),and high density lipoprotein cholesterol(HDL-C)were detected by biochemical tests.Periodic acid-schiff(PAS)staining was used to observe the pathological changes in the kidney tissue.The protein expressions of α-smooth muscle actin(α-SMA),vimentin,and advanced glycation end products(AGEs)in kidneys were detected by immunohistochemical staining.The activities of superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-PX),and the level of malondialdehyde(MDA)in kidneys were detected by using a corresponding detection kit.Enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of AGEs,carboxymethyllysine(CML),and carboxyethyllysine(CEL)in serum.The protein expressions of RAGE and the phosphorylation level of JAK1 and STAT3 in kidneys were detected by Western blot.Compared with the normal group,the levels of FBG,the area under the curve of glucose(AUCG),water intake,kidney index,24 h-UTP,tubular injury score,extracellular matrix deposition ratio of the renal glomerulus,the serum levels of Scr,BUN,TG,LDL-C,AGEs,CEL,and CML,the level of MDA,the protein expressions of α-SMA,vimentin,AGEs,and RAGE,and the phosphorylation level of JAK1 and STAT3 in kidney tissue were increased significantly(P＜0.01),while the level of HDL-C in serum and the activity of SOD,CAT,and GSH-PX in kidney tissue were decreased significantly(P＜0.01).Compared with the model group,the above indexes of the high-dose SAL group were reversed significantly(P＜0.05 or P＜0.01).In conclusion,this study suggests that SAL can alleviate oxidative stress and renal fibrosis by inhibiting the activation of AGEs-mediated RAGE/JAK1/STAT3 signaling axis,thus playing a potential role in the treatment of DN.
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