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目的研究烧伤早期RAS对心功能及心肌损伤的影响。方法健康雄性Wistar大鼠42只,随机数字法分为对照组(正常组,假伤组)和烧伤组,在大鼠30%TBSAⅢ度烧伤后1、3、6、12、24h检测血清AngⅡ,ACE,cTn-I和心肌组织AngⅡ,ACE,ACE2含量变化及血流动力和心肌力学指标(SBP,DBP,LVSP,LVEDP,+LVdp/dtmax,-LVdp/dtmax),Westernblot检测心肌组织中ACE2表达。结果烧伤后1h开始LVSP,+LVdp/dtmax,-LVdp/dtmax较对照组均明显降低(P<0.01),LVEDP明显增高(P<0.01),并于6h达到高峰,血清中cTn-I,AngⅡ,ACE和心肌组织中的AngⅡ,ACE,1h开始较对照组明显增高(P<0.01),6h达到峰值;而心肌组织中的ACE2在烧伤前后无明显变化。结论ACE-AngⅡ轴的变化趋势与血流动力、心肌力学指标及血清cTn-I变化相一致,提示RAS中重要效应轴ACE-AngⅡ轴在烧伤早期心肌损害中起着重要作用。烧伤后ACE2无明显变化,可能是导致ACE-AngⅡ轴过度激活的原因之一。
Objective To investigate the effect of RAS on cardiac function and myocardial injury in early stage of burn injury. Methods Forty-two healthy male Wistar rats were randomly divided into control group (normal group, sham group) and burn group. Serum AngⅡ was detected at 1, 3, 6, 12 and 24 hours after 30% TBSA burn in rats, ACE, cTn-I and myocardial AngⅡ, ACE, ACE2 levels and myocardial hemodynamics and myocardial mechanics indicators (SBP, DBP, LVSP, LVEDP, LVdp / dtmax, -LVdp / dtmax) . Results The levels of LVSP, + LVdp / dtmax and -LVdp / dtmax were significantly lower than those of the control group at 1 hour after burn (P <0.01), LVEDP was significantly increased (P <0.01), and peaked at 6h. The levels of cTn- (P <0.01), and reached its peak at 6h. However, ACE2 in myocardium did not change significantly before and after burn. Conclusion The trend of ACE-AngⅡ axis is consistent with the changes of hemodynamics, myocardial mechanics and serum cTn-I, suggesting that ACE-AngⅡ axis, an important axis of RAS, plays an important role in early myocardial injury. There was no significant change in ACE2 after burn, which may be one of the reasons that ACE-Ang Ⅱ axis is over-activated.