氯沙坦对心肌成纤维细胞基质金属蛋白酶-2、JNK1/2表达及增殖活性的影响

目的：研究氯沙坦通过影响高血压大鼠心肌成纤维细胞间质成分抑制心室重构的药理机制。方法：培养心肌成纤维细胞，免疫细胞化学法鉴定细胞，MTT法测氯沙坦和AngⅡ对细胞增殖活性影响的量效关系，Western Blotting测AngⅡ刺激成纤维细胞心肌JNK1／2、磷酸化JNK1／2表达的时效关系。根据实验所得AngⅡ刺激心肌成纤维细胞增殖活性作用的EC劬值、氯沙坦抑制心肌成纤维细胞活性作用的IC50值和AngⅡ刺激JNK1／2表达的最佳时间，心肌成纤维细胞分为无血清DMEM组、AngⅡ100nmol／L组、AngⅡ100nmol／L＋losartan　100nmol／L组、losartan 100nmol／L组，药物干预后分别收集各组蛋白质、培养上清液，Western blotting检测各组MMP-2、JNK1／2、磷酸化JNK1／2蛋白表达，ELISA检测分泌至培养上清液中MMP-2的量。结果：AngⅡ刺激心肌成纤维细胞增殖活性作用的EC50为53nmol／L，氯沙坦抑制心肌成纤维细胞增殖活性作用的EC50为56．3nmol／L。JNK1／2蛋白表达在AngⅡ刺激2min达高峰，随后表达逐渐降低。AngⅡ增加JNK1／2表达，氯沙坦降低AngⅡ刺激导致的JNK1／2表达。AngⅡ组MMP-2蛋白表达较无血清DMEM组明显增高，氯沙坦降低AngⅡ刺激增高的MMP-2表达。AngⅡ组MMP-2分泌较无血清DMEM组增高，氯沙坦减少AngⅡ刺激所致MMP-2分泌增高。结论：氯沙坦防治高血压引起的心室重构，可能与其对抗AngⅡ刺激心肌成纤维细胞增殖活性、MMP-2合成、分泌有关，信号通路涉及JNK1／2。

Effects of losartan on expression of matrix metalloproteinase-2,JNK1/2 and proliferation in cardiac fibroblast

AIM: To elucidate the effects of losartan on the expression ofmatrix metalloproteinases-2, JNK1/2 and proliferation in cardiac fibroblast. METHODS: Neonatal rat cardiac fibroblasts were cultured. The cells proliferation was determined by MTT. To determine effects of AngⅡ on JNK1/2 activity, cells were incubated (for 0, 2, 5, 10, 30, 60, 120 min) in serum-freemedia with AngⅡ, and the other group fibroblasts were exposed to serum-free media with or without AngⅡ and losartan (AngⅡ 100 nmol/L, AngⅡ 100 nmol/L+losartan 100 nmol/L, losartan100 nmol/L, losartan for 45 min before). Cells protein was collected with MBST buffer. The relative abundance of MMP-2, JNK1/2 and p-JNK1/2 in cells was determined by immunoblotting. The secretion of MMP-2 in media of cell culture was determined by ELISA. RESULTS: AngⅡ increased the proliferation of CFB in a dose-dependent manner, whereas losartan decreased the proliferation of CFB stimulated by AngⅡ in a dose-dependant manner, too (P＜0.05). The relative abundance of JNK1/2 was highest in AngⅡ of the 2-min-stimulated group. AngⅡincreased expression of JNK1/2 and MMP-2 protein (P＜0.05), on the contrary, losartan inhibited JNK1/2 and MMP-2 protein expression.CONCLUSION: AngⅡ induce the increase of proliferation of CFB, expression of JNK1/2 and MMP-2 in CFB, and losartan inhibits these effects of AngⅡ.