一氧化碳释放分子-2对脓毒症大鼠心肌功能障碍的影响

Effects of carbon monoxide release molecule-2 on sepsis-induced myocardial dysfunction in rats

目的探讨一氧化碳释放分子-2(CORM-2)对脓毒症大鼠心肌功能障碍的保护作用。方法将140只健康雄性SD大鼠按随机数字表法分为假手术组(Sham组)、模型组、CORM-2预处理组、灭活型一氧化碳释放分子-2(iCORM-2)预处理组、二甲基亚砜(DMSO)对照组5组,每组28只。腹腔注射10 mg/kg脂多糖(LPS)建立大鼠脓毒症模型;Sham组腹腔注射等量生理盐水(NS)。CORM-2和iCORM-2预处理组分别于注射LPS前1 h腹腔注射8 mg/kg CORM-2或iCORM-2,DMSO对照组腹腔注射等量DMSO;Sham组和模型组不给予其他处理。各组分别抽取20只大鼠观察10 d存活率。剩余8只大鼠于制模后12 h行超声心动图检查,并计算左室射血分数(LVEF)和左室缩短分数(LVFS);取下腔静脉血,采用酶联免疫吸附试验(ELISA)检测血清心肌肌钙蛋白I(cTnI)和脑钠肽(BNP)水平;之后处死大鼠取心肌组织,观察心肌病理形态学和超微结构改变。结果①生存情况:Sham组大鼠全部存活;与Sham组比较,模型组、CORM-2预处理组、iCORM-2预处理组和DMSO对照组大鼠10 d存活率均明显降低〔10%(2/20)、70%(14/20)、25%(5/20)、15%(3/20)比100%(20/20),均P<0.01〕;但CORM-2预处理组10 d存活率明显高于模型组、iCORM-2预处理组和DMSO对照组(均P<0.01)。②心功能:与Sham组比较,模型组、CORM-2预处理组、iCORM-2预处理组、DMSO对照组大鼠LVEF、LVFS均明显降低,且超声心动图提示左心室扩张明显,存在心肌功能障碍;但CORM-2预处理组大鼠LVEF、LVFS均明显高于模型组、iCORM-2预处理组和DMSO对照组〔LVEF:0.760±0.029比0.634±0.021、0.629±0.066、0.673±0.023;LVFS:(39.32±2.38)%比(29.75±1.52)%、(29.61±4.15)%、(32.43±1.66)%,均P<0.05〕,超声心动图提示CORM-2预处理后脓毒症大鼠左心室扩张程度明显减轻。③心肌损伤标志物:与Sham组比较,模型组、CORM-2和iCORM-2预处理组、DMSO对照组大鼠血清cTnI、BNP水平均明显升高;但CORM-2预处理组cTnI、BNP水平均较模型组、iCORM-2预处理组、DMSO对照组明显降低〔cTnI(ng/L):3283.54±803.50比6449.18±1105.10、5919.21±1068.27、6349.80±1153.08;BNP(ng/L):3456.62±905.85比6070.18±1287.62、5581.13±1161.17、5974.89±988.89,均P<0.05〕。④心肌组织病理学观察:模型组、iCORM-2预处理组、DMSO对照组光镜下显示大鼠心肌组织病理形态损伤严重,透射电镜下显示线粒体肿胀,部分出现空泡状改变;CORM-2预处理组心肌病理形态学及超微结构完整性明显优于脓毒症其余各组。结论CORM-2可改善脓毒症大鼠心肌功能障碍,提高大鼠存活率,尤其可保护脓毒症心肌线粒体完整。

Objective To investigate the protective effect of carbon monoxide release molecule-2(CORM-2)on sepsis-induced myocardial dysfunction in rats.Methods 140 healthy male Sprague-Dawley(SD)rats were divided into sham operation(Sham)group,model group,CORM-2 pretreatment group,inactivated carbon monoxide release molecule-2(iCORM)pretreatment group,and dimethyl sulfoxide(DMSO)control group by random number table,with 28 rats in each group.The rat sepsis model was reproduced by intraperitoneal injection of 10 mg/kg lipopolysaccharide(LPS).The rats in the Sham group were injected intraperitoneally with the same dose of normal saline(NS).The rats in the CORM-2 and iCORM-2 pretreatment groups were injected intraperitoneally with 8 mg/kg CORM-2 or iCORM-2 at 1 hour before LPS injection,respectively,and those in the DMSO group were injected intraperitoneally with the same dose of DMSO,but the rats in the Sham group and the model group were not treated after injection of NS or LPS.Twenty rats were randomly selected from each group to observe 10-day survival rate.Transthoracic echocardiography was performed on the remaining 8 rats at 12 hours after modeling,and the left ventricular ejection fraction(LVEF)and left ventricular fraction shortening(LVFS)were calculated to evaluate heart function.The blood of the inferior vena cava was harvested,then serum myocardial troponin I(cTnI)and brain natriuretic peptide(BNP)levels were measured by enzyme-linked immunosorbent assay(ELISA).Then the rats were sacrificed,and the myocardial tissues were harvested,the pathological morphology and ultrastructure of myocardium were observed.Results①Survival rates:all rats in the Sham group survived;compared with the Sham group,the survival rates of the model group,CORM-2 pretreatment group,iCORM-2 pretreatment group and DMSO control group were significantly decreased at 10 days[10%(2/20),70%(14/20),25%(5/20),15%(3/20)vs.100%(20/20),all P<0.01].However,the 10-day survival rate in the CORM-2 pretreatment group was significantly higher than those in the model group,iCORM-2 pretreatment group and DMSO control group(all P<0.01).②Cardiac function:compared with the Sham group,LVEF and LVFS in the model group,CORM-2 pretreatment group,iCORM-2 pretreatment group and DMSO control group were significantly decreased,and left ventricular dilatation was obvious,indicating myocardial dysfunction in rats.However,LVEF and LVFS in the CORM-2 pretreatment group were significantly higher than those in the model group,iCORM-2 pretreatment group,and DMSO control group[LVEF:0.760±0.029 vs.0.634±0.021,0.629±0.066,0.673±0.023;LVFS:(39.32±2.38)%vs.(29.75±1.52)%,(29.61±4.15)%,(32.43±1.66)%,all P<0.05],and the left ventricular dilatation in the septic rats was attenuated.③Myocardial injury markers:compared with the Sham group,serum cTnI and BNP levels were significantly higher in the model group,CORM-2 pretreatment group,iCORM-2 pretreatment group and DMSO control group.However,the levels of cTnI and BNP in the CORM-2 pretreatment group were significantly lower than those in the model group,iCORM-2 pretreatment group and DMSO control group[cTnI(ng/L):3283.54±803.50 vs.6449.18±1105.10,5919.21±1068.27,6349.80±1153.08;BNP(ng/L):3456.62±905.85 vs.6070.18±1287.62,5581.13±1161.17,5974.89±988.89,all P<0.05].④Myocardial histopathological observation:optical microscope showed that the pathological changes in myocardial tissue of the model group,iCORM-2 pretreatment group and DMSO control group were severe.Transmission electron microscopy showed mitochondrial swelling,and some vacuoles changed.But the myocardial pathological morphology and mitochondrial ultrastructural integrity of the CORM-2 pretreatment group were significantly better than other groups of sepsis.Conclusion CORM-2 can attenuate myocardial dysfunction and improve survival rate of septic rats,especially to protect myocardial mitochondrial integrity in sepsis.