核因子κB受体活化因子及其配体在5／6肾切除大鼠肾脏中表达及缬沙坦对其影响

The expression of RANK and RANKL in kidney tissue of 5/6 subtotal nephrectomy rats and related effects of valsartan treatment

目的探讨核因子κB受体活化因子(RANK)及其配体(RANKL)在5／6肾切除大鼠(STNX)残肾中表达的意义,以及血管紧张素受体拮抗剂(ARB)缬沙坦对其表达的影响。方法制备5／6肾切除的SD大鼠动物模型,分为未给药组、治疗组及假手术组。治疗组在5／6肾切除后即给予缬沙坦治疗,大鼠分别于第4、8、12周杀检。第12周时用ELISA方法检测大鼠血清中骨保护蛋白(OPG)及RANKL水平;显微镜观察肾脏病理变化;免疫组化方法及Western印迹方法分析RANK／RANKL／OPG蛋白表达;RT-PCR检测RANK／RANKL／OPG的mRNA表达。结果(1)第12周时假手术组尿蛋白量为(6．1±0．6)mg／24 h;未给药组为(19．0±1．5)mg／24．h:治疗组为(13．4±1．2)mg／24 h,3组间的差异有统计学意义(P均<0．01)。(2)第12周时未给药组及治疗组肾脏均有明显硬化,但治疗组硬化程度较未给药组轻。(3)未给药组RANK及RANKL蛋白及mRNA的表达均高于治疗组及假手术组,3组间的差异有统计学意义(P均<0．01)。OPG蛋白及mRNA的表达在3组间无显著性差异。(4)血清中OPG及RANKL含量在3组间的差异亦无统计学意义。结论在5／6肾切除大鼠残肾中表达上调的RANK和RANKL可能参与了肾小球硬化的发生发展。抑制RANK和RANKL的表达可能是缬沙坦延缓肾小球硬化的原因之一。

Objective To investigate the expression of receptor activator of NF-kappa B （RANK）, its ligand （RANKL） and osteoprotegerin （OPG） in kidney tissue of 5/6 subtotal nephrectomy （STNx） rats, and the effect of valsartan on above expression. Methods Seventy-two male SD rats were divided into STNx control group （n=24）, STNx ＋ valsartan treatment group（n=24） and sham operation group （n=24）. In valsartan treatment group, the SD rats received valsartan （15 mg·kg^-1·d^-1）, an angiotensin II type 1 （AT1） receptor antagonist, after STNx. At week 4, 8 and 12 after operation, the kidney pathology was examined by light microscopy respectively. RANK, RANKL and OPG expression in kidney tissue was examined by histochemisty, Western blot and RT-PCR. Serum levels of RANKL and OPG were examined by ELISA at week 12. Results （1）At week 12 after operation, the 24-hour urine protein was （13.4±1.2） mg in valsartan group, （19.0±1.5） mg in STNx group and （6.1±0.6） mg in sham operation group （all P〈0.01）. （2）Glomendar sclerosis degree in valsartan treatment group was gentler than that in STNx group. （3）In sham operation rat kidneys, RANK and RANKL protein expressed in a few tubules and were absent in glomeruli. RANK and RANKL mRNA expressed in glomeruli in valsartan group and STNx group. Treatment with valsartan manifestly reduced mRNA and protein expression of RANK and RANKL in glomemli （P 〈 0.01 ）. There was no differences of OPG expression among these 3 groups. Serum levels of OPG and RANKL were similar in 3 groups at week 12. Conclusions RANK and RANKL may play a role in progressive renal injury following STNx. Inhibition of RANK and RANKL expression may be one of the meehanisms by whieh AT1 receptor antagonist attenuates renal injury after renal ablation.