Objective: To investigate the expression level of podocyte slit diaphragm protein in rats after one-time exhaustive exercise, to explore the effect of PKC inhibitor on the protein expression level, and to reveal the mechanism of PKC in the formation of exercise-induced proteinuria. Methods: Thirty male SD rats were randomly divided into control group (C), exercise group (E) and exercise combining with PKC inhibitor group (EPI), with 10 rats in each group. Rats in group E and EPI performed one single bout of exhaustive exercise (25 m/min), rats in group EPI were intraperitoneally injected with a PKC inhibitor (chelerythrine, 5 mg/kg) 1 day and 1 hour before exercise respectively, while rats in group C and E were injected with the same volume of saline. Results: ①Compared with group C, the levels of urine protein, uric acid, urine sugar, blood urea, and blood uric acid of rats in group E were increased significantly (P＜0.05), the level of blood glucose was reduced significantly (P＜0.01), and renal ROS production was increased significantly (P＜0.01). The expressions of nephrin and podocin protein in renal tissue were decreased significantly (P＜ 0.05), while the expressions of PKC, Nox2, and Nox4 protein were increased significantly (P＜0.05). ②Compared with group E, the levels of urinary protein,urine glucose and blood urea in EPI group were decreased significantly (P＜0.05), the level of blood glucose was increased significantly (P＜0.01), renal ROS production was reduced significantly (P＜0.01). the expressions of nephrin and podocin protein in renal tissues of the EPI group were increased significantly (P＜0.05), while the expressions of PKC and Nox2 protein was reduced significantly (P＜0.05, P＜0.01). Conclusion: One-time exhaustive exercise can down-regulate the expressions of nephrin and podocin through PKC/Nox/ROS pathways in the kidney of rats; PKC inhibitor alleviates the decrease in the expression of podocyte slit diaphragm protein caused by exhaustive exercise, and prevents the occurrence of exercise-induced proteinuria.
目的: 观察大鼠在一次性力竭运动后肾脏裂孔膜蛋白的表达水平,探究PKC抑制剂对其蛋白表达水平的影响,揭示PKC在运动性蛋白尿形成中的作用机制。方法: SD雄性大鼠30只随机分为对照组(C)、运动组(E)、运动联合PKC抑制剂组(EPI),每组10只。E组和EPI组大鼠分别进行一次性跑台力竭运动(25 m/min),EPI组大鼠运动前1 d及1 h腹腔注射PKC抑制剂白屈菜红碱(chelerythrine,5 mg/kg),C组和E组注射相应体积的生理盐水。运动后即刻麻醉后,取血液、尿液及肾脏组织,使用化学比色法检测尿蛋白、尿酸、尿糖、血尿素、血尿酸、血糖水平,使用荧光探针法检测肾脏ROS水平,使用Western blot法检测肾脏PKC、Nox2、Nox4、nephrin、podocin蛋白表达。结果: ①与C组相比,E组尿蛋白、尿酸、尿糖、血尿素、血尿酸显著增多(P＜0.05),血糖显著减少(P＜0.01),肾脏ROS生成显著增多(P＜0.01),肾脏nephrin、podocin蛋白表达明显降低(P＜0.05),PKC、Nox2、Nox4蛋白表达明显增多(P＜0.05);②与E组比,EPI组尿蛋白、尿糖、血尿素显著减少(P＜0.05),血糖显著增加(P＜ 0.01),肾脏ROS生成显著降低(P＜0.01),EPI组肾组织中nephrin、podocin蛋白表达明显增加(P＜0.05),PKC、Nox2蛋白表达明显降低(P＜0.05)。结论: 一次性力竭运动通过PKC/NOX/ROS途径使大鼠肾脏裂孔膜蛋白nephrin、podocin表达下调;PKC抑制剂缓解力竭运动导致的肾脏裂孔膜蛋白表达下降,预防运动性蛋白尿的发生。.
Keywords: NADPH oxidase (Nox); exercise-induced proteinuria; nephrin; podocin; protein kinase C (PKC); reactive oxygen species (ROS).