1,25(OH)_2D_3对Thy-1肾炎大鼠Ki67、mTOR表达的影响

Effect of 1,25-dihydroxyvitamin D_3 influence on expressions of Ki67 and m TOR in Thy-1 nephritis model of rat

目的研究1,25-二羟基维生素D3[1,25(OH)2D3]对Thy-1肾炎模型大鼠Ki67和哺乳动物雷帕霉素靶蛋白(m TOR)表达的影响,并探讨其机制。方法 90只清洁级雄性SD大鼠随机分为对照组、模型组、1,25(OH)2D3组,每组30只。模型组与1,25(OH)2D3组尾静脉注射抗Thy-1单克隆抗体建立肾炎模型,对照组给予等剂量生理盐水。建模后,1,25(OH)2D3组给予1,25(OH)2D30.5μg/d灌胃,连续给药21 d,对照组及模型组给予等体积花生油。分别于给药后第1、3、7、14、21天每组随机处死6只大鼠,处死前1 d收集24 h尿液进行24 h尿蛋白定量;取各组肾组织标本,经HE和PAS染色后进行肾脏病理损害评分,免疫组化法检测肾组织中Ki67、m TOR表达。结果模型组和1,25(OH)2D3组大鼠在建模后第1天尿蛋白水平升高,模型组第3天达高峰,至第14天恢复至正常水平,1,25(OH)2D3组大鼠第1、3、7天的尿蛋白水平均低于模型组(P<0.05)。1,25(OH)2D3组大鼠肾组织病理损害程度第3、7天较模型组减轻(P<0.05),Ki67、m TOR蛋白表达水平较模型组降低(P<0.05)。24 h尿蛋白定量,Ki67表达水平,m TOR表达水平及肾组织病理损害评分彼此间均呈正相关。结论 1,25(OH)2D3可抑制Thy-1肾炎模型大鼠肾小球系膜细胞的增殖,其作用机制可能与减少Ki67、m TOR的表达有关。

Objective To study the expressions of Ki67 and mTOR in Thy-1 nephritis model of rat who were given 1,25-dihydroxyvitamin D3[1,25（OH）2D3] and to explore its mechanism. Methods Healthy male SD rats （n=90） were random-ly divided into three groups： control group, model group, 1,25（OH）2D3 treatment group （n=30 in each group）. Model group and 1,25（OH）2D3 treatment group were intravenously injected with anti-Thy1 monoclonal antibody once via tail vein while the control group were administrated with same volume of normal saline through the same route. 1,25（OH）2D3 were adminis-trated at 0.5μg per day intra-gastrically for consecutive 21 days in 1,25（OH）2D3 treatment group while equal volume of pea-nut oil were given in control group and model group. Six rats were randomly selected from each group and sacrificed at the 1st , 3rd , 7th , 14th and 21st after drug intervention. Twenty four hour urine sample were collected in each rat just before it was culled to detect 24-hour urinary protein excretion. Renal tissue samples were harvested and stained with hematoxylin＆amp;eo-sin （H＆E） and PAS to determine the renal pathological variation and the expressions of mTOR and Ki67 were assessed by immunohistochemistry. Results Urine protein begin to be detected at the first day after model was established, peaked at the 3rd days then started dropping until the 14th day when urine sample turned to normal. Urine protein levels were lower in 1, 25（OH）2D3 treatment group at the 1st,3rd,7th day after model establishment than those in model group（P〈0.05）. Compared with model group, the pathological damage of renal tissue in 1,25（OH）2D3 treatment group were alleviated at the 3rd and 7th day after model establishment （P 〈 0.05）. Expressions of Ki67 and mTOR in 1, 25（OH）2D3 treatment group were reduced compared with those in model group （P〈0.05）. Twenty four hour urinary protein and expressions of Ki67 and mTOR as well as renal pathological damage were all positively correlated with each other. Conclusion 1,25（OH）2D3 can inhibit the proliferation of glomerular mesangial cells in Thy-1 nephritis model of rat. And its therapeutic mechanism may be associated with down reg- ulating expressions of Ki67 and mTOR.