家兔心肌梗死慢性期梗死周边区交感神经重构与电重构的相关研究

Relationship between sympathetic remodeling and electrical remodeling at infracted border zone of rabbit with chronic myocardial infarction

目的探讨家兔心肌梗死(心梗)慢性期梗死周边区交感神经重构与电重构的相关性。方法结扎家兔冠状动脉前降支制备心梗模型作为心梗组(20只),假手术组10只作为对照。8周后开胸分别测量梗死周边区基础状态下跨室壁复极离散度(TDR)、交感神经刺激时TDR、交感神经刺激引起TDR的变化(ΔTDR)和室颤阈值。免疫组织化学法观察梗死周边区生长相关蛋白43(GAP43)和酪氨酸羟化酶(TH)阳性纤维的分布和密度。结果心梗组存活18只,假手术组10只均存活。心梗组GAP43和TH阳性纤维的密度显著高于假手术组(P<0.05)。心梗组GAP43和TH阳性纤维的密度与基础状态下TDR、交感神经刺激时TDR及ΔTDR均呈显著正相关(P均小于0.01),与室颤阈值有负相关趋势(P=0.07,P=0.09)。结论家兔心梗慢性期梗死周边区交感神经重构与电重构显著相关。

Objective To investigate the relationship between sympathetic remodeling and electrical remodeling at the infracted border zone （IBZ） of rabbit with chronic myocardial infarction （MI）. Methods Thirty rabbits were randomly assigned into two groups ： MI group （ n = 20 ） ： ligation of the anterior descending coronary; sham operation （SO） group （ n = 10） ： without conorary ligation. Eight weeks after surgery, transmural dispersion of repolarization （TDR） at baseline, during sympathetic nerve stimulation, TDR change （△TDR） during sympathetic nerve stimulation and ventricular fibrillation threshold （VFT） were measured at the IBZ in MI group and corresponding zone in SO group. The distribution and densities of growth associated protein 43 （GAP43） and tyrosine hydroxylase （TH） positive nerves in ventricle were also detected with immunohistochemical techniques. Results Eighteen rabbits in the MI group and 10 in the SO group survived to the end of the study. The densities of GAP43 and TH at the IBZ in the MI group were significantly higher than that at the corresponding zone in the SO group （ both P 〈 0.05 ）. The densities of GAP43 and TH in MI rabbits positively correlated with TDR at baseline, TDR or △TDR during sympathetic nerve stimulation （all P 〈0. 01 ） and both showed a weak negative correlation with VFT （r = -0.44, P = 0. 07; r = -0. 41, P = 0. 09, respectively）. Conclusion Sympathetic remodeling is correlated with electrical remodeling at the IBZ in rabbits with chronic MI.