肾损伤分子1在低渗造影剂肾病模型大鼠肾组织的表达及缺氧诱导因子1α对其的影响

Expression of kidney injury molecule-1 in contrast induced tubular injury and the effect of hypoxia-inducible factor-1α

目的:观察低渗造影剂碘必乐诱导的造影剂肾病大鼠肾小管上皮细胞损伤情况和肾损伤分子1(kidney injury molecule-1,KIM-1)的表达以及缺氧诱导因子1α上调对其的影响。方法:清洁级雄性SD大鼠45只,分为对照组(CON组,n=15),造影剂肾病模型组(CM组,n=15)及氯化钴预处理组(Cocl2+CM组,n=15)。为建立造影剂肾病大鼠模型,应用碘必乐(3gI/kg)前,依次尾静脉注射吲哚美辛(INDO,10mg/kg)和左旋硝基精氨酸甲酯(L-NAME,10mg/kg)。分别于造模后第2h、12h、24h、48h、72h处死动物,并检测血肌酐值,HE染色评估肾小管损伤程度,免疫组化、Western Blot及Real time-PCR方法测定肾组织中KIM-1蛋白及mRNA表达水平。结果:(1)与对照组相比,CM组造模后第2h、12h血清肌酐值无显著性差异(P>0.05),24h、48h、72h均显著升高(P值均<0.01),显示造模成功,Cocl2+CM组较同一时间点CM组血清肌酐值显著下降(P<0.01);(2)HE染色可见CM组24h、48h、72h均出现不同程度的急性肾小管损伤,伴有上皮细胞刷状缘脱落、空泡变性、细胞脱落及再生,部分肾小管结构破坏,髓质区病变较皮质病变更严重;Cocl2+CM组较同一时间点的CM组肾损伤评分显著降低(P<0.05);(3)免疫组化、Western Blot和Real time-PCR结果表明,自造模后2h始,CM组较阴性对照组大鼠肾组织KIM-1蛋白及mRNA表达水平均显著增加(P<0.05),而Cocl2+CM组较同一时间点的CM组KIM-1表达水平显著减少(P<0.05)。结论:低渗造影剂碘必乐诱导的急性肾小管上皮细胞损伤大鼠肾组织KIM-1表达水平显著增加,较血肌酐更早的反映肾损伤,上调肾组织HIF-1α表达可以减轻肾小管上皮细胞损伤,KIM-1表达亦相应降低。

Objective：To observe the renal tubular cell injury induced by low-osmolar contrast medium iopamidol, the expression of kidney injury molecule-1 （KIM-1） and the effect of upregulation of hypoxia-inducible factor-1α（HIF-1α） in rats. Methodology ： Fourty five clean male SD rats with mean of weight （ 150 ± 20） g were divided into three groups. They were control group （ CON group, n = 15 ）, contrast medium （iopamidol） induced nephropathy group （ CM group, n = 15） and pretreated with Cocl2 then with iopamidol group （ Cocl2 ＋ CM group, n = 15 ）, and each sacrificed at 2h, 12h, 24h ,48h ,72h, respectively. To develop the model of contrast medium induced nephropathy, those rats were pretreated with indomethacin （10 mg/kg ） and L-NAME （10 mg/kg ） before administration of iopamidol （3g l/kg）. The level of serum creatinine was measured. The histopathologic degrees of renal tubular cell injury were scored in HE-stained sections. The expressions of KIM-1 protein and mRNA in kidney were semiquantitatively measured with immunohistochemistry, western blot and RT-PCR, respectively. Results：The Level of serum creatinine in CM groups displayed a significant increase at 24, 48 and 72 hour compared with that in CON group （ P 〈 0.05 ）, so the rat model has succeed. Compared with CM group, the serum creatinine showed a significant decrease in CoCl2 ＋ CM group （P 〈 0. 05）. In CM group, the histological examination with HE revealed the different extents of actue tubular injury with tubular brush border loss, vacuolar degeneration, cell loss and regeneration and focal kidney structure damage, which were more severe in medulla than those in cortical tissue. The semiquantitative renal tubular cell injury scores were reduced in Cocl2 ＋ CM group compared with the CM group at the same time point （ P 〈 0.05 ） , respectively. The expressions of KIM-1 protein and mRNA were significantly increased in CM group compared with that in CON group （P 〈 0. 05）, but it was significantly decreased in Cocl2 ＋ CM group detected by immunohistochemistry, westem blot and RT-PCR method （ P 〈 0. 05 ）. Conclusion： The expressions of KIM-1 were increased significantly in low-osmolar contrast medium iopamidol induced actue tubular cell injury model, which changed earlier than serum creatinine. Upregulated the level of HIF-1α ameliorated the renal tubular cell injury and reduced the expression of KIM-1 accordingly.