【摘要】 目的：明确Orai1通道对自发性高血压大鼠（spontaneously hypertensive rats,SHR）心房纤维化及房颤（atrial fibrillation,AF）易感性的影响。方法：采用45～46周龄的Wistar大鼠（n=16）及SHR（n=13）分别作为对照组和实验组，快速起搏心房观察两组大鼠AF的可诱发性。HE和Masson染色观察两组大鼠心房组织的纤维化程度。Western blot检测两组大鼠心房组织纤维化相关的Ⅰ型胶原蛋白（collagen type Ⅰ,Col1）、Ⅲ型胶原蛋白（collagen type Ⅲ,Col3）、基质金属蛋白酶2（matrix metalloproteinase 2,MMP2）和MMP9，以及钙信号通路相关蛋白Orai1、钙调神经磷酸酶（calcineurin,CaN）和活化T细胞核因子3（nuclear factor of activated T cells 3,NFAT3）的表达。在原代培养的乳大鼠心肌成纤维细胞（cardiac fibroblasts,CFs）上，利用腺病毒转染使其过表达Orai1后，采用Western blot检测细胞中纤维化相关因子的表达变化，并观察CaN抑制剂环孢素A（cyclosporine A,CsA）对其表达的影响；用Fluo4 AM荧光探针法观察过表达Orai1的CFs中钙浓度的变化。结果：与Wistar大鼠相比，SHR的AF诱发率显著增加（P<0.05），心房组织中纤维化相关因子MMP2、MMP9、Col1和Col3蛋白表达显著上调（P<0.05）,Orai1、CaN和NFAT3亦显著上调（P<0.05）。过表达Orai1可促进CFs中纤维化相关因子MMP2、MMP9、Col1和Col3的表达（P<0.05），同时，Orai1通道介导的钙离子内流明显增加（P<0.05）;CsA可明显逆转CFs中Orai1过表达的效应（P<0.05）。结论：Orai1通道上调可激活Ca²⁺/CaN/NFAT3通路，促进CFs纤维化相关因子分泌；高血压大鼠心房纤维化增加可能与Orai1通道上调有关。更多还原

【Abstract】 AIM:To investigate the role of Orai1 channel in atrial fibrosis and the susceptibility to atrial fibrillation（AF）in spontaneously hypertensive rats（SHR）.METHODS:Wistar rats and SHR aged 45 to 46 weeks were used as the control group and the experimental group,respectively. The inducibility of AF in the 2 groups was observed by rapid atrial pacing. HE staining and Masson staining were used to observe the degree of fibrosis of rat atrial tissues. The protein expression levels of collagen type Ⅰ（Col1）,collagen type Ⅲ（Col3）,matrix metalloproteinase 2（MMP2）,MMP9,Orai1,calcineurin（CaN）and nuclear factor of activated T cells 3（NFAT3）were detected by Western blot. Primarily cultured neonatal rat cardiac fibroblasts（CFs）were transfected with Ad-Orai1 to overexpress Orai1,or were pretreated with cyclosporin A（CsA;an inhibitor of CaN）before Orai1 overexpression. The protein expression levels of fibrosis-related factors were dected by Western blot,and the intracellular Ca²⁺concentration of CFs was detected by Fluo4 AM fluorescent probes.RESULTS:The AF inducibility was significantly increased in SHR compared with Wistar rats（P<0. 05）. The protein expression levels of Orai1,calcineurin,NFAT3 and the fibrosis-related factors（MMP2,MMP9,Col1and Col3）were significantly up-regulated in the atrial tissues from SHR（P<0. 05）. Overexpression of Orai1 promoted the expression of fibrosis-related factors（P<0. 05）,and significantly increased the Ca²⁺entry in CFs（P<0. 05）,while CsA obviously reversed these effects（P<0. 05）.CONCLUSION:Up-regulation of Orai1 channel activates Ca²⁺/CaN/NFAT3pathway and promotes the secretion of fibrosis-related factors in CFs,which is related to the increase in atrial fibrosis in hypertensive rats.更多还原