阻断Notch信号通路延缓尿酸诱导大鼠肾脏损伤的机制

Blocking Notch signal pathway delayed uric acid-induced renal injury in rats

目的探讨γ-分泌酶抑制剂DAPT对尿酸诱导大鼠肾脏损伤中的作用及其机制。方法21只雄性SD大鼠随机分为正常对照组(control,n=7)、高尿酸模型组(OA+UA,n=7)、DAPT治疗组(OA+UA+DAPT,n=7)。OA+UA组予2%氧嗪酸2.5 mL/100 g灌胃,3次/d,同时予0.1 mmol/L尿酸饮水,OA+UA+DAPT组在造模的同时每天予γ-分泌酶抑制剂DAPT500μg/100 g腹腔注射。对照组给予正常食物,腹腔注射等量生理盐水,模型建立8周时处死大鼠。用HE、Masson染色分析肾脏病理形态学变化,qRT-PCR、Western blot检测Notch信号通路Notch1/Jagged1/Hes1、转化生长因子-β(transforming growth factor-β,TGF-β)和a平滑肌肌动蛋白(a-smooth muscle actin,a-SMA)的mRNA和蛋白表达水平,并用免疫组化观察上述指标在大鼠肾脏的定位。结果与对照组相比,OA+UA组HE染色发现部分肾小管上皮细胞肿胀、脂肪变性、部分肾小管上皮细胞脱落,管腔扩张变形,部分肾小管萎缩,可见褐色针状放射状尿酸盐结晶。Masson染色肾小管间质可见明显波浪状的胶原纤维呈亮绿色沉积。Notch1/Jagged1/Hes1、TGF-β1和α-SMA表达水平明显增加。DAPT治疗后大鼠肾脏病理损伤较模型组的改变减轻,肾脏间质纤维化减少,Notch1/Jagged1/Hes1表达水平下调,同时TGF-β1和α-SMA表达减少。结论Notch信号通路抑制剂DAPT可以延缓高尿酸引起的大鼠慢性肾病损伤。

Objective To investigate the effect and mechanism ofγ-secretase inhibitor DAPT on uric acid-induced renal injury in rats.Methods Twenty-one male SD rats were randomly divided into normal control group(control,n=7),hyperuricemia model group(OA+UA,n=7),and DAPT treatment group(OA+UA+DAPT,n=7).The OA+UA group was given 2.5 mL/100 g of 2%oxazine by gavage,3 times a day,and 0.1 mmol/L uric acid was given to drink water at the same time.OA+UA+DAPT was given Notch signaling pathway specific inhibitor every day while modeling.γ-secretase inhibitor DAPT 500μg/100 g intraperitoneal injection.The control group was given normal food and intraperitoneally injected with the same volume of normal saline.Seven rats in each group were sacrificed at 8 weeks after model establishment.The histopathological changes of the kidney were determined by hematoxylin-eosin staining(HE)and Masson staining.qRT-PCR and Western blot were used to detect the level of Notch signaling pathway receptor Notch1,ligand Jagged1 and hair division-related enhancer 1(Hes1),TGF-β1 andα-SMA.The location of the above indicators in the kidneys of rats was observed by immunohistochemistry.Results Compared with the control group,HE staining in the OA+UA group showed that some renal tubular epithelial cells were swollen and shed.The lumens were expanded and deformed.Part of renal tubules were atrophied and widening.With inflammatory infiltration,the brown needle-like radial urate crystals can be seen in the renal interstitium at 8 weeks.Masson staining showed obvious wavy collagen fibers in the tubulointerstitium,which were bright green staining.While the morphological changes were milder in OA+UA+DAPT group.Compared with the control group,the expression levels of Notch1/Jagged1/Hes1,TGF-β1 andα-SMA were significantly increased in the OA+UA group.Compared with the model group,the damage of renal in the rats after DAPT treatment were significantly alleviated.The renal interstitial fibrosis was reduced,As same as the expression levels of Notch1/Jagged1/Hes1,the expression of TGF-β1 andα-SMA decreased in OA+UA+DAPT group.Conclusions The Notch signaling pathway is activated during uric acid-induced renal injury in rats.DAPT,the Notch signaling pathway inhibitor,would delay the renal injury in rats induced by uric acid.