硝基酪氨酸对糖尿病肾病大鼠肾脏NF-κB、MCP-1及TGF-β1表达的影响

摘要

目的 观察硝基酪氨酸(NT)对糖尿病肾病(DN)大鼠肾脏核因子-κB (NF-κB)、单核细胞趋化蛋白-1(MCP-1)和转化生长因子-β1 (TGF-β1)表达的影响,探讨其在DN发生发展中的作用机制.方法 用链脲佐菌素腹腔注射法建立DN大鼠模型,造模成功的大鼠随机分3组:DN模型组、DN+NT组和DN+NT+Ebselen组(NT抑制剂),另设正常对照组.各组分别干预8周后,观察24 h尿蛋白定量变化,采用免疫组织化学染色检测肾脏组织NF-κB、MCP-1及TGF-β1蛋白的表达,实时荧光定量PCR法检测肾组织NF-κB、MCP-1及TGF-β1 mRNA表达,光镜观察肾脏病理改变.结果 与DN模型组比较,DN+NT组大鼠24 h尿蛋白定量、肾脏组织中NF-κB、MCP-1和TGF-β1的蛋白及mRNA水平均显著增加,肾脏病理改变加重;NT抑制剂Ebselen可明显减轻这些变化.结论 硝基酪氨酸可上调DN大鼠肾脏组织NF-κB、MCP-1及TGF-β1蛋白及其mRNA的表达,加重炎性反应,促进DN的进展.%Objective To observe the effect of nitrotyrosine on renal expressions of nuclear factor-κB (NF-κB), monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-β1 (TGF-β1) in rats with diabetic nephropathy (DN). Methods Rat DN models established by a single intraperitoneal injection of streptozotocin (STZ) were randomly allocated into model group, nitrotyrosine group and ebselen group, with untreated rats as the normal control group. The rats were given the corresponding drugs for 8 weeks, and after the last administration, the 24-h urinary protein level was measured and the kidneys of the rats were harvested for detecting the protein and mRNA expressions of NF-κB, MCP-1 and TGF-β1 with immunohistochemistry and RT-PCR, respectively. The pathological changes of the kidneys were assessed microscopically. Results Compared with those in the model group, the 24-h urinary protein level and expressions of NF-κB, MCP-1 and TGF-β1 mRNA and protein in the renal tissues were significantly increased by nitrotyrosine treatment, which also caused worsened renal pathology, while treatment with ebselen significantly ameliorated these changes. Conclusion Nitrotyrosine can up-regulate the mRNA and protein expressions of NF-κB, MCP-1 and TGF-β1 and aggravate the inflammatory reaction in the renal tissue of DN rats to promote the progression of DN.