【摘要】 目的探讨基质金属原蛋白-2(MMP-2)、MMP-9、基质金属蛋白酶特异性组织抑制物-1(TIMP-1)和TIMP-2在高氧肺损伤中的作用及维甲酸(RA)的保护作用机制。方法建立高氧(FiO285%)暴露早产SD大鼠肺损伤模型,应用RT-PCR法检测MMP-2、MMP-9、TIMP-1和TIMP-2mRNA表达,采用明胶酶谱检测MMP-2和MMP-9酶原及活酶表达,采用Western blot技术检测TIMP-1和TIMP-2蛋白表达。结果与空气组比较,高氧暴露4、7、14d,MMP-2、MMP-9和TIMP-1 mRNA的表达均显著升高(P均<0.01),MMP-2活酶、MMP-9酶原及活酶和TIMP-1蛋白的表达明显上调(P<0.05);RA对空气暴露下它们的表达均无明显影响(P均>0.05),但不同程度下调高氧暴露后MMP-2、MMP-9、TIMP-1mRNA的表达和MMP-2活酶、MMP-9酶原及活酶的表达,进一步提高TIMP-1蛋白表达;高氧、RA对TIMP-2 mRNA和蛋白的表达均无明显影响(P均>0.05)。结论高氧暴露明显改变MMPs/TIMPs的表达,在肺泡形成关键时期,MMPs/TIMPs之间平衡关系的破坏是造成肺发育受阻和纤维化的重要因素;通过协调MMPs/TIMPs之间的表达,改善肺泡结构,降低肺纤维化程度,从而逆转高氧所致肺损伤,是RA发挥保护作用的重要机制之一。更多还原

【Abstract】 Objectives To explore the role of matrix metalloproteinase-2,-9(MMP-2,MMP-9)and tissue inhibitor of metalloproteinase-1,-2(TIMP-1,TIMP-2)in hyperoxia lung injury and the protective effect of retinoic acid(RA)on hyperoxia lung injury.Methods Model of hyperoxia lung injury was established with exposure the premature Spragne Dawkey(SD)rats to hyper-concentration oxygen of FiO2 85%.The levels of MMP-2,MMP-9,TIMP-1 and TIMP-2 mRNA were detected with semi-quantitative reverse transcription polymerase chain reaction(RT-PCR).The expression of active MMP-2 and pro/active MMP-9 was measured with zymography,the protein abundance of TIMP-1 and TIMP-2 was determined with Western blot.Results Levels of MMP-2,MMP-9 and TIMP-1 mRNA were significantly higher in the model on day 4,day 7,and day 14 of hyperoxia-exposure in comparison with the expression from lungs of normoxic pups(P < 0.01).Levels of active MMP-2,pro/active MMP-9 and TIMP-1 were significantly higher after exposure to oxygen than that of room air exposed groups on each experimental day(P < 0.05).RA had no effect on the expression of MMP-2,MMP-9 and TIMP-1 in the pups exposed to room air(P > 0.05).Though both were placed in the hype-roxic environment,the expression levels of mRNA for MMP-2,MMP-9 and TIMP-1 in premature pups treated with RA were significantly lower than non-RA treated pups on each experimental day.Levels of active MMP-2 and pro/active MMP-9 were decreased markedly after RA treatment in hyperoxia exposed pups.In addition,RA treatment led to a further elevation of TIMP-1 levels.But hyperoxia,RA had no effect on the expression of mRNA TIMP-2(P > 0.05).Conclusions The expression of MMPs/TIMPs was markedly changed by exposure to hyperoxia.The balance of MMPs/TIMPs was diturbed by hyperoxia injury during alveolarization of lung in premature rat leding to lung development inhibition and lung fibrosis.RA had a protective effect on hyperoxia-induced lung injury by regulating MMPs/TIMPs expression,improving alveolar structure,decreasing fibrosis and reversing the hyperoxia-induced lung injury.更多还原