钙敏感受体及紧密连接蛋白-14在草酸钙结石大鼠肾组织中的表达及意义

摘要

目的：初步探讨钙敏感受体（CaSR）和紧密连接蛋白（Claudin）-14在肾草酸钙结石大鼠肾组织中的表达及意义。方法30只雄性SD大鼠随机分为对照组和结石组各15只，采用1%乙二醇和2%氯化铵每日2 mL灌胃诱导制作大鼠肾草酸钙结石模型。免疫组织化学检测CaSR蛋白表达；RT-PCR检测Claudin-14 mRNA表达；West-ern-Blotting分别检测CaSR和Claudin-14蛋白表达；全自动生化分析仪检测2组大鼠肾功能、血及尿生化指标。结果光镜下结石组有大量结石结晶形成，血清肌肝（Cr）、尿素氮（BUN）、24 h尿钙及尿量较对照组升高（P＜0.01），2组间血钙、尿pH差异无统计学意义。结石组Claudin-14 mRNA及CaSR蛋白表达较对照组升高（P＜0.01），Claudin-14蛋白在结石组大鼠肾组织中呈特异性高表达，对照组未检测到Claudin-14蛋白表达；结石组大鼠肾组织中CaSR和Claudin-14蛋白表达呈正相关，同时，CaSR、Claudin-14蛋白表达与24 h尿钙排泄量也呈正相关。结论 CaSR和Claudin-14表达增高可通过增加尿钙排泄量，进而参与结石的形成。%Objective To investigate the expressions of calcium sensitive receptor (CaSR) and tight junction protein (Claudin)-14 in renal calcium oxalate stone rat model. Methods Thirty male SD rats were randomly divided into control group (n=15) and model group (n=15). The rat model of renal calcium oxalate stone was established by gavaging 1%glycol (2 mL/d) and 2% ammonium chloride. The expression of CaSR protein was detected using immunohistochemical assay. RT-PCR was used to detect the Claudin-14 mRNA expression. The expression levels of CaSR and Claudin-14 protein were de-tected by Western blot assay respectively. The full automatic biochemical analyzer was used to detect rat renal function and changes of blood and urine biochemical indices. Results A large stone crystallization was observed under light microscope in model group. The serum levels of Cr, BUN, 24-h urine calcium and urine volume were significantly higher in model group than those of control group (P<0.01). There were no significant differences in serum calcium level and urinary pH value be-tween two groups. The expression levels of Claudin-14 mRNA and CaSR protein were significantly higher in model group than those of control group (P<0.01). The Claudin-14 protein expression was specifically higher in renal tissues of model group. There was no Claudin-14 protein expression in control group. There was a positive correlation between CaSR and Claudin-14 protein expression in renal tissues of model group. Also, CaSR and Claudin-14 protein expressions were posi-tively correlated with the 24-h urine volume. Conclusion The increased expressions of CaSR and Claudin-14 involved in the formation of kidney stone by increasing the urinary calcium excretion.