Calcineurin通路在肺气肿大鼠膈肌起搏治疗中的作用与机制

Diaphragm remodeling and weakness associated with chronic obstructive pulmonary plays a key role in the progression of respiratory insufficiency. Our previous studies showed that diaphragm pacing (DP) can restored contractile properties of diaphragm in mechanical ventilated rats. As known that electric stimulation can trigger intracellular calcium mobilization and excitation-contraction coupling in skeletal muscle. However, how DP with different mode influence calcium mobilization in diaphragm cell remains unclear. As one of the most important intracellular calcium sensors，calcineurin regulates myocyte hypertropy and differentiation. Therefore, there is of important significance to investigate the role and mechanism of calcineurin pathway in DP therapy for emphysema rats. We speculate that DP with different mode may exert differential effects on calcium mobilization and calcineurin pathway, resulting the different efficacy in reversing pathological remodeling of diaphragm. To prove the above hypothesis, we will detect levels of resting calcium currents and calcium transient induced by DP using calcium fluorescent indicators. And we will also investigate the the changes of downstream targets controlled by calcineurin pathway with method of molecular biology and immunohistochemistry. Then we will analyze the intracellular mechanism of the function and morphological changes of diaphragm in emphysema rats to provide a basis for rational application of DP with different mode.

慢性阻塞性肺病引起的膈肌肌力下降与结构重塑在呼吸功能不全的病程发展中扮演着重要的角色，我们的前期研究已证实膈肌起搏治疗能够有效保护机械通气大鼠膈肌的收缩功能。众所周知，电刺激能够触发骨骼肌细胞内钙离子的动员及兴奋收缩偶联，但不同模式的膈肌起搏对膈肌细胞内钙动员的影响仍有待研究。作为细胞内最重要的钙离子感受器之一，钙调磷酸酶调控着肌细胞的生长与分化，因此研究钙调磷酸酶通路在肺气肿大鼠膈肌起搏治疗中的作用和机制具有重要意义。我们推测不同模式的膈肌起搏可能对肌细胞内钙动员水平及钙调磷酸酶通路活化影响不同，而这也是造成其逆转膈肌病变的疗效存在差异的原因所在。为验证上述假说，我们将采用钙离子荧光探针检测静息钙电流与钙瞬变的水平，采用分子生物学与免疫组化的方法研究钙调磷酸酶调控的下游靶点，最后我们还将分析肺气肿大鼠膈肌功能与形态学发生病理改变的内在机制，为不同模式膈肌起搏治疗的合理应用提供依据。