富马酸二甲酯对肾草酸钙结石大鼠肾功能和氧化应激的影响及其机制研究

目的 基于p38丝裂原活化蛋白激酶（MAPK）信号通路，探讨富马酸二甲酯对肾草酸钙结石大鼠肾功能及氧化应激的影响及其作用机制。方法 将30只SPF级SD雄性大鼠随机分为对照组、模型组、富马酸二甲酯组，每组10只。其中模型组、富马酸二甲酯组大鼠腹腔注射0.25% L-羟脯氨酸2.5 kg/（kg·d）复制肾草酸钙结石大鼠模型。富马酸二甲酯组大鼠腹腔注射富马酸二甲酯25 mg/（kg·d），连续28 d，对照组、模型组同时腹腔注射等量生理盐水。采用全自动生化分析仪检测大鼠尿蛋白、尿钙，以及血肌酐水平；HE染色检测大鼠肾组织草酸钙晶体形成情况；试剂盒检测血清超氧化物歧化酶（SOD）活性、丙二醛（MDA）及活性氧簇（ROS）水平；Western bloting检测大鼠肾组织p38 MAPK通路蛋白相对表达量。结果 与对照组比较，模型组和富马酸二甲酯组大鼠肾组织SOD活性降低，草酸钙晶体含量、尿蛋白、尿钙、血肌酐及肾组织MDA、ROS水平，p-JNK、p-p38蛋白相对表达量升高（P <0.05）；但富马酸二甲酯组大鼠SOD活性高于模型组（P <0.05），肾组织草酸钙晶体含量、尿蛋白、尿钙、血肌酐，肾组织MDA、ROS水平，p-JNK、p-p38蛋白相对表达量低于模型组（P <0.05）。结论 富马酸二甲酯可能通过抑制p38 MAPK通路活化，抑制肾脏组织氧化应激反应，从而抑制肾草酸钙结石形成，进而保护肾功能。

The effect of dimethyl fumarate on renal function and oxidative stress in calcium oxalate stone-forming rats and its mechanisms

Objective To investigate the effect of dimethyl fumarate on renal function and oxidative stress in calcium oxalate stone-forming rats by focusing on p38 mitogen-activated protein kinase (MAPK) pathway.Methods Thirty SPF male SD rats were randomly divided into control group, model group and dimethyl fumarate group. The rats in model group and dimethyl fumarate group were calcium oxalate stone formers. Rats in the dimethyl fumarate group were given intraperitoneal injection of dimethyl fumarate at a dose of 25 mg/(kg·d) for consecutive 28 days, while those in the control group and the model group were given intraperitoneal injection of the same amount of normal saline at the same time. The levels of urine protein, urine calcium and blood creatinine were detected by automatic biochemical analyzer, and the formation of calcium oxalate crystals in the rat kidney was observed by HE staining. The activity of superoxide dismutase (SOD), the content of malondialdehyde (MDA) and the level of reactive oxygen species (ROS) in the serum were determined by corresponding kits, and the level of proteins associated with the p38 MAPK pathway was detected by Western blotting.Results Compared with the control group, SOD activity in the kidney of rats in the model group and dimethyl fumarate group were decreased, while the contents of the calcium oxalate crystal content, urine protein, urine calcium, blood creatinine, and the levels of MDA, ROS, p-JNK, and p-p38 proteins in the kidney of rats in the model group and dimethyl fumarate group were increased (P < 0.05). In addition, SOD activity in renal tissues of rats in the dimethyl fumarate group were higher than those in the model group (P < 0.05), whereas the levels of calcium oxalate crystal content, urine creatinine, urine protein, urine calcium, blood creatinine, and the levels of MDA, ROS, p-JNK, and p-p38 proteins in the kidney of rats in the dimethyl fumarate group were lower than those in the model group (P < 0.05).Conclusions Dimethyl fumarate may protect renal function by inhibiting the activation of p38 MAPK pathway, oxidative stress, and calcium oxalate stone formation in the kidney.