左卡尼汀对单侧输尿管梗阻大鼠肾间质纤维化的保护作用

Renoprotective effects of L-carnitine on tubulointerstitial fibrosis in a rat model of unilateral ureteral obstruction

目的探讨左卡尼汀(LC)对单侧输尿管梗阻(UUO)大鼠模型肾间质纤维化的保护作用机制。方法38只雄性SD大鼠建立UUO模型后随机分为UUO7组(n=8)、UUO7+LC组(n=8)、UUO14组(n=8)、UUO14+LC组(n=8)和假手术组(n=6),其中UUO7+LC组、UUO14+LC组给予腹腔注射LC〔200 mg/(kg·d)〕,分别于第7、14天处死大鼠;假手术组给予等量生理盐水。Masson染色、HE染色、电镜观察各组肾间质纤维化程度;免疫组化和Western印迹法分别检测炎性因子、致纤因子、氧化应激、染色体相关基因的表达。结果LC治疗明显减轻UUO大鼠肾小管间质纤维化程度,伴随着炎性介质〔单核细胞趋化蛋白(MCP)-1、Toll样受体(TLR)-2、骨桥蛋白(OPN)〕和致纤因子〔转化生长因子(TGF)-β1、结缔组织生长因子(CTGF)〕的表达下调,呈时间依赖性。UUO所致氧化应激表现为烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶(NOX)-2表达增加和抗氧化酶线粒体锰超氧化物歧化酶(MnSOD)表达下降,这种改变与染色体功能失调及其调控基因表达失衡紧密相关,LC逆转了上述所有指标。结论LC通过干预氧化应激和保护染色体功能对UUO大鼠肾脏具有抗炎、抗纤维化作用。

Objective To evaluate the renoprotective effects of L-carnitine(LC)on tubulointerstitial fibrosis in a rat model of unilateral ureteral obstruction(UUO).Methods Thirty-eight Sprague-Dawley rats underwent UUO surgery and were randomly assigned to five subgroups and treated daily with LC for 14 days,and rats were sacrificed at the 7 th or 14 th day.The degree of tubulointerstitial fibrosis was assessed in terms of Masson trichrome and HE stain and transmission electron microscopy,and immunohistochemistry and Western blot were employed to evaluate the expression of profibrotic and proinflammatory cytokines and mitochondria-related genes.Results LC treatment significantly decreased the degree of tubulointerstitial fibrosis induced by UUO,and this was accompanied by attenuating the expression of profibrotic and proinflammatory cytokines in a time dependent manner.The increased oxidative stress(dysregulation of oxidant antioxidant enzymes)caused by UUO was associated with mitochondrial dysfunction and imbalance of mitochondria-controlling genes,and these were abrogated by administration of LC.Conclusions LC protects against the progression of tubulointerstitial inflammation and fibrosis by interfering oxidative stress and preserving mitochondrial integrity in an obstructed kidney.