Ezrin蛋白在糖尿病肾病鼠肾小球的表达及活性维生素D对其的影响

目的：观察Ezrin蛋白在糖尿病肾病（DN）大鼠肾小球的表达以及活性维生素D1，25-（OH）2D3]对其表达的影响。方法：Wistar大鼠随机分为对照组和糖尿病肾病模型组；后者经腹腔注射链佐脲菌素（STZ）诱导DN大鼠模型，再随机分DN组和1，25-（OH）2D3组。1，25-（OH）2D3组皮下埋置渗透性微量泵，给予1，25-（OH）2D3 0．03ng／g·d^-1，连用8周。检测大鼠血糖（Glu）、肾重／体重（KW／BW）、24h尿蛋白（24hUP）、血肌酐（Scr）、尿足细胞（UPC）。采用间接免疫荧光检测肾小球Ezrin蛋白的表达与分布。WT-1免疫组化染色检测每个肾小球足细胞数目。结果：与对照组相比，DN组Glu、KW／BW、24hUP、Scr、UPC显著升高；肾小球Ezrin表达显著下降，足细胞数目减少。DN组与1，25-（OH）2D3组Glu水平无显著性差异，1，25-（OH）2D3组KW／BW、24hUP、Scr、UPC较DN组显著降低；而肾小球Ezrin表达及足细胞数目显著增加。对照组Ezrin蛋白荧光染色沿肾小球毛细血管壁均匀线型分布；DN组呈不连续的粗颗粒样分布；1，25-（OH）2D3组部分呈短线型荧光。Ezrin表达荧光强度与肾小球足细胞数目呈正相关（FS=0．51，P〈0．01），与24hUP、UPC呈负相关（rs=-0．43，-0．45，P〈0．01）。结论：1，25-（OH）2D3可减少DN鼠肾小球Ezrin的表达，减少足细胞脱落，维持肾小球足细胞数量。

Effect of 1,25-Dihydroxyvitamin D3 on the expression of Ezrin of glomeruli in rats with diabetic nephropathy

Objective:To observe the effect of 1,25-Dihydroxyvitamin D3(1,25-(OH)2D3)on the expression of Ezrin in glomeruli of rats with diabetic nephropathy(DN).Methods:Wistar rats were randomly divided into two groups:control group and DN model group which was induced by peritoneal injection of streptozotocin(STZ).After these models were successfully established,they were randomly divided into two groups:DN group and 1,25-(OH)2D3 group.1,25-(OH)2D3 group was embedded with the osmotic minipump for giving 0.03 ng/g-1·d-1 1,25-(OH)2D3 for 8 weeks.Blood glucose(Glu),the ratio of kidney weight/body weight(KW/BW),24-hour urinary protein(24 hUP),serum creatinine(Scr)and urinary podoctye(UPC)were measured.The expression and distribution of Ezrin in glomeruli was detected by indirect immunofluorescence.Podocyte number per glomeruli was determined by WT-1 immunohistochemistry.Results:Compared with control group,the level of Glu,KW/BW,24 hUP,Scr,UPC in DN group were significantly increased.The expression of Ezrin in glomeruli statistically decreased.Average numbers of podocytes per glomeruli was dramatically reduced.There was no significant difference of Glu between DN and 1,25-(OH)2D3 group.KW/BW,24 hUP,Scr,UPC were significantly lower in 1,25-(OH)2D3 group than in DN group.The expression of Ezrin and the numbers of podocytes per glomeruli in 1,25-(OH)2D3 group were higher than those in DN group.In control group,fluorescent staining of Ezrin was detected as a fine,linear-like pattern along the glomerular capillary loop;Ezrin staining changed to a discontinuous,coarse granular pattern in DN rats,short linear pattern was observed in part of the glomeruli in 1,25-(OH)2D3 group.Fluorescence intensity of Ezrin showed a positive correlation with the numbers of podocytes per glomeruli(rs =0.51,P<0.01),and a negative correlation with 24 hUP,UPC(rs =-0.43,-0.45,P<0.01).Conclusions:1,25-(OH)2D3 could contribute to increasing Ezrin expression in DN rats,reduce podocyte detachment to preserve podocyte number.