降钙素基因相关肽对大鼠心肌缺血损伤热休克蛋白70和核因子-κB的影响

Effect of CGRP on HSP70 and NF-κB in Rats with Myocardial Ischemia Injury

目的观察降钙素基因相关肽(CGRP)对大鼠心肌缺血损伤热休克蛋白70(HSP70)和核因子-κB(NF-κB)的影响,探讨CGRP的抗心肌缺血损伤的作用及其机制。方法将24只雄性SD大鼠随机分为正常对照组(Ⅰ组)、缺血损伤组(Ⅱ组)和缺血损伤+CGRP组(Ⅲ组),应用异丙肾上腺素(ISO)建立大鼠心肌缺血损伤模型。观察3组大鼠心电图ST段(J点)的变化;测定血清磷酸肌酸激酶(CPK)、磷酸肌酸激酶同工酶(CK-MB)、肿瘤坏死因子-α(TNF-α)水平;测定心肌髓过氧化物酶(MPO)活性;免疫组化法检测心肌NF-κB和HSP70的表达;观察心肌组织超微结构的改变。结果Ⅲ组大鼠的心电图ST段偏移程度和血清CK-MB、CPK、TNF-α水平、MPO活性以及心肌组织HSP70、NF-κB表达与Ⅱ组的比较,差异均有统计学意义(P<0.01),心肌组织结构损伤减轻。结论CGRP对大鼠心肌缺血损伤具有保护作用,可能与促进HSP70表达、抑制NF-κB表达有关。

Objective To investigate the effect of calcitonin gene - related peptide （CGRP） on the myocardial ischemia injury and its mechanism through observing the influence of CGRP on the expression of heat shock protein （HSP） 70 and the activation of nuclear factor （NF） - κB in rats with myocardial ischemia injury. Methods Totally 24 male SD rats were randomly divided into control group （group Ⅰ）, MI group （group Ⅱ）, MI ＋ CGRP group （group Ⅲ）. The myocardial ischemia injury model was induced by subcutaneous injection of isoproterenol （ISO）. The following changes were measured ： the excursion at ST -junction （J site） of ECG; the activities of serum creatine phosphate kinase （CPK）, creatine phosphokinase- isoenzyme - MB （CK -MB） and tumor necrosis factor- alpha （TNF -α） ; the activity of myocardial myoperoxidase （MPO） ; the activation of NF - κB and the expression of HSP70 in the myocardial by immunohistochemistry technique; the myocardial ultrastructure under electronic microscope. Results Compared with the group Ⅱ, in the group Ⅲ, the excursion at ST - junction of ECG, activities of serum CPK, CK - MB and TNF - α, activity of MPO, expressions of HSP70 and NF - κB in the myocardial showed significant difference （ P 〈0. 01 ）. The myocardial ultrastruture under electronic microscope was more improved. Conclusion CGRP can protect myocardial ischemia injury, which may be associated with the upper - regulation of HSP70 expression and the down - regulation of NF - κB.