罗格列酮对肾间质损伤的防护作用及其机制

目的探讨罗格列酮对肾间质纤维化的保护作用及其机制。方法以大鼠单侧输尿管梗阻(UUO)为模型,在不同的时间点(3d、7d、14d)观察梗阻侧肾间质基质含量;各组肾皮质间质巨噬细胞浸润情况;致纤维化的转化生长因子-β1(TGF-β1)的表达情况;肾皮质多种与肾脏纤维化相关的结缔组织生长因子(CTGF)、骨形态发生蛋白7(BMP7)、Smad6信号蛋白等的mRNA表达及BMP7、PAI1的蛋白表达。结果罗格列酮能改善UUO所致的肾间质纤维化程度(P<0.05);显著减少间质巨噬细胞浸润数量;下调肾脏组织TGF-β1的表达(P<0.05);减少TGF-β1下游致纤维化因子CTGF及PAI1的表达;同时上调TGF-β1信号传导中抑制性因子BMP7和Smad6的表达(P<0.05)。结论罗格列酮能保护UUO所致的肾间质炎症和纤维化损伤。其可能的作用机制包括抑制肾间质炎症细胞浸润;减少TGF-β1表达、阻止TGF-β信号传导、抑制TGF-β1下游效应因子CTGF和PAI1的表达,增加抗纤维化抗炎作用的BMP-7蛋白表达等,从而从多层面阻断TGF-β1的致纤维化作用。

Protection of rosiglitazone against renal interstitial lesion and its mechanism

OBJECTIVE: To investigate the protection of rosiglitazone (RSG) against renal interstitial lesion and its mechanism. METHODS: Male adult SD rats were randomly divided into 5 groups: Sham group, undergoing sham operation; Sham + RSG group, undergoing sham operation and treated with RSG (30 mg.kg(-1).d(-1)); UUO group, undergoing unilateral left ureter obstruction; UUO + RSG5 group, undergoing UUO and treated with RSG (5 mg.kg(-1).d(-1)); and UUO + RSG30 group, undergoing UUO and treated with RSG (30 mg.kg(-1).d(-1)). Except the Sham group, the other groups were divided into 3 subgroups of 6 approximately 8 rats to be killed 3, 7, and 14 days after the intervention and their left kidneys were taken out to undergo light microscopy by Masson staining to observe the renal interstitial fibrosis index and to undergo immunohistochemistry with mice anti-rat ED-1 antibody to calculate the ED-1 (specific marker antigen on the surface of monocyte/macrophage) positive cells. Homogenate of renal cortex was made. ELISA was used to detect the protein expression of transforming growth factor beta(1) (TGF-beta(1)), bone morphogenetic protein (BMP)-7, and PAI-1 gene. RT-PCR was used to detect the mRNA expression of BMP-7 and TGF-beta(1) downstream effector genes: CTGF and Smad6. RESULTS: Fourteen days after the intervention, the fibrosis index of the UUO group were significantly increased and the fibrosis index values of both UUO + RSG5 and UUO + RSG30 groups were significantly lower than that of the UUO group (both P = 0.000) with a significant difference between the 2 UUO + RSG groups. Three days after the intervention, the number of ED-1 positive cell began to increase in the UUO group and peaked 7 days after, however, the number of ED-1 positive cells of the 2 UUO + RSG groups were significantly lower than that of the UUO group. TGF-beta(1) mRNA and protein were highly expressed in the UUO group, however, the expression of TGF-beta(1) mRNA in the 2 UUO + RSG groups was significantly lower, especially in the UUO + RSG30 group, in comparison with the UUO group (both P < 0.05). The CTGF mRNA expression was increased time-dependently in the UUO group, however the CTGF mRNA expression of the 2 UUO + RGS groups was significantly inhibited dose- and time-dependently (all P < 0.05). In comparison with that in the Sham group, the Smad6 mRNA expression was significantly increased in the Sham + RSG group (P < 0.05), and was decreased time-dependently in the UUO group; however, the decrease of Smad6 mRNA expression was significantly reversed in the 2 UUO + RSG groups, especially in the UUO + RSG30 group (P < 0.05). The expression of BMP-7 protein and mRNA was significantly lower in the UUO group time-dependently. However, the BMP-7 mRNA expression of the 2 UUO + RSG group, especially of the UUO + RSG30 group, was significantly higher than that of the UUO group (both P < 0.05). The PAI-1 protein expression of the UUO group was significantly higher 7 and 14 days after (both P < 0.05), however, the PAI-1 protein expression of the 2 UUO + RSG groups was significantly lower than that of the UUO group (both P < 0.05). CONCLUSION: RSG inhibits the renal interstitial macrophage infiltration, downregulates the expression of the down-stream target genes, and up-regulate the BMP-7 expression, thus blocking the renal fibrosis.