1,25-(OH)_2D_3对糖尿病大鼠ZO-1表达的影响

Effects of 1,25-Dihydroxyvitamin D_3 on the Expression of ZO-1 in the Kidney of Diabetic Rats

目的观察糖尿病(DM)大鼠肾小球ZO-1蛋白的表达,1,25-(OH)2D3对ZO-1蛋白表达及分布的影响。方法Wistar大鼠随机分为3组:对照组、糖尿病组(DM组)、1,25-(OH)2D3组。链脲菌素(STZ)腹腔注射建立糖尿病动物模型,1,25-(OH)2D3组在糖尿病建立时即开始渗透性微量泵按3ng/100g·d皮下给予1,25-(OH)2D3,给药10周处死小鼠,检测血糖、半胱氨酸蛋白酶抑制剂(CysC)、尿红细胞、24h尿蛋白定量(24hUPE);光镜观察肾小球细胞数,细胞外基质(ECM)聚积;Western印迹检测ZO-1蛋白的表达;免疫金荧光染色电镜观察肾小球ZO-1分布的改变。结论DM组大鼠CysC、尿红细胞、24hUPE均高于1,25-(OH)2D3组,差异均有统计学意义(P<0.05)。1,25-(OH)2D3组大鼠较DM组肾小球细胞数减少,细胞外基质聚积减轻(P<0.05或P<0.01)。Western印迹示1,25-(OH)2D3组和对照组肾小球ZO-1表达无显著差异,均明显高于DM组(P<0.01)。免疫金荧光染色显示DM组肾小球ZO-1表达缺失及易位分布明显,1,25-(OH)2D3组ZO-1的表达缺失及易位分布较轻。结论1,25-(OH)2D3可减少尿蛋白的排泄,抑制肾小球细胞数及细胞外基质的增殖,增加足细胞特异蛋白ZO-1的表达,减少其易位,对肾脏有保护作用。

Aim To observe the effects of 1,25-（OH）2D3 on glomerular ZO-1 expression and distribution in the glomeruli of diabetic rats. Methods Wistar rats were randomly divided into the control group, diabetes group （DM group ）, and 1,25-（OH）2D3 （ 1,25- （ OH ） 2 D3 group）. Diabetes was induced by peritoneal injection of streptozotocin （STZ）. Treatment with 1,25-（OH）2D3 （ 3 ng/100g·d） started on the diabetic model by subcutaneous implantation of osmotic minipumps in 1,25-（ OH）2D3 group. After administration of 1,25-（ OH）2D3 for 10 weeks, the rats were sacrificed, blood sugar （ BG）, cystatin C （ Cys C ） , haematuria, 24-hour urinary protein excretion （ 24hUPE ） were measured. Glomerular cells and extracellular matrix （ECM） were observed by light microscope. The expression level of ZO-1 was examined by western blot. The distribution of ZO-1 in glomeruli after immunogold fluorescent staining was observed by electron microscopy. Results Compared with 1,25- （OH）2D3 group, Cys C, haematuria ,24hUPE in DM group were significantly increased （ P 〈 0.05 ）. Glomerular cells and the accumulation of ECM in 1,25- （OH） 2D3 group were lower than those in DM group（ P 〈 0.05 or P 〈 0.01 ）. There was not significant difference in the expression of glomerular ZO-1 between control group and 1,25-（ OH）2D3 group, whereas the expression of glomerular ZO-1 in control group and 1,25- （OH）2 D3 group was higher than that of DM group （ P 〈 0.01 ）. Histologically ,obvious absence and translocation of the expression of ZO-1 in glomeruli were seen in DM group by immunogold fluorescent staining. The changes were attenuated in 1,25-（ OH）2D3 group. Conclusion 1,25-（OH）2D3 could decrease the excretion of proteinuria, inhibit glomerular cells and ECM proliferation, significantly increase the expression and reduce translocation of ZO-1 to protect kidney in diabetic rats.