目的：：观察兔房颤模型心房肌组织髓过氧化物酶( MPO)、基质金属蛋白酶( MMP)-2和MMP-9的表达,并探讨三者与房颤时心房结构重构的关系。方法：20只新西兰大白兔,开胸后于左心房植入起搏电极,随机分为2组：快速心房起搏组( RAP组)以600 min-1的频率快速起搏心房3周；假手术组( sham组)不予起搏。起搏前、后行超声心动图检查评价心房和心室的结构和功能,行心房burst刺激检测房颤诱发率；起搏后采用Masson染色评价心房的间质纤维化程度,采用RT-qPCR和Western blot检测心房MPO、MMP-2和MMP-9 mRNA和蛋白的表达水平。结果：起搏3周后,与sham组相比,RAP组兔左心房明显扩张伴收缩功能障碍,左心室的结构和功能变化不明显；RAP组房颤诱发率和间质纤维化百分比均明显增加,且心房MPO、MMP-2、MMP-9 mRNA和蛋白的表达明显增加。结论：持续快速心房起搏兔房颤模型会出现明显心房结构重构,心房MPO、MMP-2和MMP-9表达上调可能是其潜在的分子机制。%AIM:To investigate the expression of myeloperoxidase ( MPO) , matrix metalloproteinase ( MMP)-2 and MMP-9 in the atrial myocardium, and their potential effects on atrial structural remodeling in a rabbit atrial fibrilla-tion ( AF) model. METHODS: The sternotomy was performed and the pacing electrode was fixed to the left atria of 20 New Zealand white rabbits. The animals were randomly divided into 2 groups:rapid atrial pacing ( RAP) group and sham group. The rabbits in RAP group were subjected to RAP for 3 weeks. The structure and function of the atria and ventricle were analyzed by echocardiography. Atrial burst stimulation was performed to test AF inducibility. The atrial fibrosis was e-valuated by Masson trichrome-staining. The mRNA and protein levels of MPO, MMP-2 and MMP-9 were detected by RT-qPCR and Western blot. RESULTS: After 3 weeks of RAP, obvious left atrial enlargement and dysfunction were ob-served, but almost no change of left ventricular diameter and function was found in RAP group compared with sham group. AF inducibility, atrial interstitial fibrosis and the mRNA and protein levels of MPO, MMP-2 and MMP-9 were all signifi-cantly increased in RAP group compared with sham group. CONCLUSION:Obvious atrial structural remodeling is found in the rabbit AF model induced by sustained RAP, and the up-regulation of MPO, MMP-2 and MMP-9 may be the potential molecular mechanism of atrial structural remodeling.
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