2型糖尿病肾病大鼠肾脏MCP-1与氧化应激相关性研究

Correlation on renal MCP-1 and oxidative stress in rats with type 2 diabetic nephropathy

目的观察2型糖尿病肾病(diabetic nephropathy,DN)大鼠肾脏氧化应激指标与单核细胞趋化蛋白-1(monocyte chemotactic protein-1,MCP-1)表达水平的相关性,并通过普罗布考早期干预来探讨抗氧化剂对糖尿病肾脏的保护机制。方法设立对照(N组,健康对照组)的同时,采用链脲佐菌素(STZ)35 mg/kg体质量剂量腹腔注射,构建2型糖尿病肾病大鼠模型,将造模成功的2型糖尿病大鼠分别给予普罗布考(P组,普罗布考组)和NADPH氧化酶抑制剂(Apocynin)(A组,Apocynin组)干预。12周时,测量24 h尿蛋白、尿微量白蛋白以及FPG、Cr、BUN;然后处死观察肾脏病理及超微病理改变;免疫组化(S-P)法检测肾组织NT和MCP-1的表达量;RT-PCR半定量NF-κB mRNA表达,并作相关分析。结果①P组和A组较DN组可以明显改善尿白蛋白、血Cr、BUN水平和肾脏肥大指数(P<0.05)。②DN组大鼠肾脏NT和MCP-1的表达呈明显正相关(r=0.0),且显著高于N组(P<0.05)。③P组肾脏NT、MCP-1表达较DN组明显下降(P<0.05),但和A组无显著差异。结论普罗布考可能通过抑制氧化应激反应下调MCP-1过表达对肾脏的损伤,起到保护肾脏的作用。

Objective To investigate the correlation between monocyte chemotactic protein-1（MCP-1） expression and oxidative stress indices in kidney of type 2 diabetic nephropathy（DN） rat model,and through probucol early intervention to explore the protective mechanism of antioxidants on diabetic kidney.Methods Twenty-four male Wistar rats of 8 weeks age were randomly divided into a normal control group（n=6） and a model group（n=18）.Rats of the normal control group were fed with regular diet,while rats of the model group were fed with high-fat high-sugar diet and 4 weeks later were given an intraperitoneal injection of 35 mg/kg streptozotocin（SZT）.The successfully constructed type 2 diabetic nephropathy rat models were then randomly divided into a DN group（n=5）,a P group（n=6） and an A group（n=6）.Rats of the P group were given 61 mg/kg Probucol and high-fat high-sugar diet.Rats of the A group were given 200 mg/kg Apocynin（NAPDH oxidase inhibitor） and high-fat high-sugar diet.At week 12,the levels of 24-hour urine protein,urinary micro albumin,serum creatinine and blood urea nitrogen were measured.The rats were then sacrificed.Renal and ultrasturctural pathological changes were examined.Renal tissue NT and MCP-1 expressions were measured by immunohistochemical assay.NF-κB mRNA expression was semi-quantified by RT-PCR,and correlation analysis was performed.Results ①Compared with the DN group,the P group and A group had significantly lower levels of urinary micro albumin,serum creatinine,blood urea nitrogen and kidney hypertrophy index（P0.05）.②MCP-1 expression in the DN group was positively correlated with NT expression and renal function（r=0.0）;both MCP-1 and NT levels were significantly higher than those in the N group（P0.05）.③NT and MCP-1 expressions in the P group were significantly decreased as compared with those in the DN group（P0.05）,but not significantly different from those in the A group.Conclusion Antioxidant may down-regulate MCP-1 expression through inhibition of oxidative stress in diabetic nephropathy and therefore protect renal function by reducing injury resulted from MCP-1 overexpression.