心肌梗死后心肌T型钙通道基因表达及在心肌重塑中的作用

Effect of gene expression of myocardial T-type calcium channel on myocardial remodeling

目的 :探讨心肌梗死后心肌重塑过程中T型钙通道基因表达的变化及其在心肌重塑中的作用。方法 :Wistar大鼠 18只 ,随机分为心肌梗死后 3h、2 1d组及假手术组 3组 ,每组各 6只 ,建立心肌梗死后心肌重塑模型。假手术组不结扎冠状动脉。采用RT PCR方法检测T型钙通道基因表达的变化 ;采用免疫组织化学方法染色和计算机图像分析方法检测Ⅰ型、Ⅲ型胶原和纤维连接蛋白 (FN)表达的变化 ;采用原子吸收光谱法测定心肌总Ca2 + 浓度。结果 :心肌梗死后 2 1d心肌重塑过程T型钙通道基因在邻近梗死区非梗死心肌表达 ,而远离梗死区心肌不表达 ;假手术组不出现表达。心肌Ⅰ型、Ⅲ型胶原 ,FN在梗死组心肌显著表达 ,与假手术组比较差异有显著性意义 (P <0 .0 5或 <0 .0 1)。心肌总Ca2 + 测定显示 ,梗死组比假手术组明显增加 (P <0 .0 5 )。结论 :T型钙通道与心肌梗死后心肌重塑密切相关。钙通道基因表达的意义可能在于增加心肌细胞膜钙通道密度。Ca2 + 经过钙通道进入细胞触发心肌重塑过程。提示 ,临床上开发和利用T型钙通道阻滞剂对防治心肌梗死后心肌重塑。

Objective:To evaluate the effect of gene expression of T type calcium channel on myocardial remodeling.Methods: Rat models of myocardial remodeling by ligation of coronary artery were set up, 18 rats were randomly divided into three groups. Gene expression of T type calcium channel were tested by reverse transcription and polymerase chain reaction (RT PCR). Cardiac collagen subtype Ⅰ, Ⅲ, fibronectin (FN) were studied by immunohistochemistry and image analysis. Cardiac total Ca 2+ was tested by atomic absorption/flame emission spectrophotometer.Results:The fetal pattern of T type calcium channel were expressed in non infarction myocardium close to the infarction area on the 21st day after myocardial infarction, but not in remote area. Cardiac collagen Ⅰ, Ⅲ, FN were significantly increased(P< 0.05 or P< 0.01 )in myocardial infarction group compared with those in sham group. Cardiac total Ca 2+ in the infarction group was increased (P< 0.05 ) compared with that in sham group.Conclusion:Fetal pattern of T type calcium channel is related with myocardial remodeling after myocardial infarction.