摘要
目的观察烧伤早期心肌局部肾素-血管紧张素系统(RAS)变化及其对心肌肌浆网(SR)钙运转功能的影响,探讨烧伤早期心功能障碍的发病机制。方法大鼠随机分为对照组(8只,不予致伤),烧伤组(40只,致30%Ⅲ度烧伤),治疗组(40只,Lisinopril 灌胃3天后致30%Ⅲ度烧伤),测定烧伤前(对照组)及烧伤后3,8,24 h 左心功能变化,心肌组织血管紧张素转换酶(ACE)活性,血管紧张素Ⅱ(A_Ⅱ)及钙离子(Ca^(2+))含量变化,测定心肌 SR Ca^(2+)-ATPase 活性,吸 SR Ca^(2+)运转功能的变化。结果烧伤组大鼠左心室内压变化最大速率(±dp/dt_(max))明显降低。心肌组织 ACE 活性、A_Ⅱ及 Ca^(2+)含量显著增加,心肌 SR Ca^(2+)-ATPase 活性降低,SR Ca^(2+)摄取减少。治疗组预防性给予 ACE 抑制剂 Lisinopril 可显著降低烧伤后心肌组织 ACE 活性,减少 A_Ⅱ产生,Ca^(2+)含量降低,增加SR Ca^(2+)-ATPase 活性,SR Ca^(2+)摄取增加,左心室功能明显改善。结论烧伤早期心肌局部 RAS 迅速激活,抑制 SR Ca^(2+)运转,可能是心肌 RAS 促进烧伤早期心功能障碍的作用机制之一。
Objective To observe changes in cardiac renin-angiotensin and its effect on sarcoplas- mic reticulum(SR)calcium transport function,and investigate the mechanism underlying cardiac dysfunc- tion in early postburn stage.Methods Rats were divided into three groups:control group(n=8,without burns),burn group(n=40,30% TBSA full-thickness burns),and treatment group(n=40,garage Lisinopril for 3 days before 30% TBSA burns).The left ventricular(LV)contractile function was mea- sured at 3,8,24 hours postburn.Angiotensin converting enzyme(ACE)activities,the contents of an- giotensin Ⅱ(A_Ⅱ)and calcium in myocardium were also measured.In addition,Ca^(2+)-ATPase activities and calcium transport function in SR were determined.Results The maximal rates of LV pressure rise(± dp/dt_(max))and fall(-dp/dt_(max))in burn group were significantly lower than that in control group.The ACE activities,A_Ⅱ levels,as well as calcium contents in myocardium increased markedly in burn group. Ca^(2+)-ATPase activities and Ca^(2+)uptake function in SR decreased significantly in burn group.After treat- ment with ACE inhibitor-Lisinopril,the ACE activities,A_Ⅱ levels and calcium contents were significantly dereased compared to the burn group.Meanwhile,Ca^(2+)-ATPase activities,calcium uptake function and LV contractile function decreased markedly.Conclusion The cardiac renin-angiotensin system is activated rapidly after severe burns and inhibits the calcium transport function which may play an important role in cardiac contractile dysfunction following burns.
关键词
烧伤
心功能
肌浆网
RAS
心肌肌浆网
Burns
Cardiac function
Sarcoplasmic reticulum
Cardiac renin-angiotensin system
