内毒素休克大鼠心肌组织中H_2S/CSE体系的变化及意义

Changes and significance of myocardial H_2S/CSE system in endotoxemic rats

目的探讨内毒素休克大鼠血浆中硫化氢(H2S)含量变化和心肌组织中H2S/CSE体系变化及其改变的意义。方法采用静脉注射脂多糖(LPS)的方法制备内毒素休克大鼠模型,将Wistar大鼠随机分为正常对照组、LPS组、LPS+炔丙基甘氨酸(propargylglycine,PPG,H2S代谢酶抑制剂)组、LPS+NaHS(H2S供体)组。观察给药后4 h内大鼠颈动脉平均压(mean arterial pressure,MAP)的变化,根据血压入选动物模型。测定不同时间点血浆H2S含量,并测定心肌组织中H2S含量及测定CSE的酶活性,运用RT-PCR方法,对CSE表达情况进行半定性分析。电子显微镜下观察心肌组织形态学变化。结果①与正常对照组相比,LPS组大鼠血压迅速下降,血浆H2S含量显著增高,且血浆中H2S含量与血压呈显著负相关,LPS注射后1、2、4 h时相关系数分别为-0.936、-0.913和-0.908(均P<0.05);心肌组织中H2S含量明显升高,CSE活性和CSE mRNA表达也明显升高,并出现心肌组织损伤;②给予NaHS后,与LPS组相比,大鼠血浆H2S含量增高,血压明显下降(均P<0.05),心肌组织损伤加重,心肌组织中H2S含量、CSE活性及CSE mRNA的表达增高;③给予PPG后,与LPS组相比,能显著抑制血浆H2S含量的增高,并可显著减轻LPS所致的血压下降(均P<0.05)和心肌组织损伤,降低心肌组织中H2S含量、CSE酶活性及CSE mRNA的表达;④与正常对照组相比,LPS组和LPS+NaHS组CSE mRNA表达均显著增高,而LPS+PPG组则表达降低。结论内源性硫化氢(H2S)作为一种损伤性因素参与了内毒素休克的病理生理过程,且心肌组织中H2S/CSE体系参与了心肌损伤过程并造成心脏功能下降。

Objective To explore the changes of plasma hydrogen sulfide（H2S） level and cardiac H2S/CSE system in endotoxemic rats and their significance.Methods A rat model of endotoxemia induced by injection of lipopolysaccharide（LPS） was developed.Wistar rats were divided into four groups： control group,LPS group,LPS ＋ propargylglycine（PPG,a CSE inhibitor） group and LPS ＋ NaHS（H2S donor） group.The mean arterial pressure（MAP） of rats within 4 h was observed,H2S contents in plasma in different time interval were determined,then executed the rats at 4 h,and determined the contents of H2S and activity of CSE in the cardiac muscle.RT-PCR method was used to conduct a semi-qualitative analysis of the expression of CSE.The morphological structure of cardiac muscle was observed.Results A dministration of LPS caused a sustained fall in MAP within 4 h,and significant increases in a H2S content in plasma（P0.05）.Plasma H2S content was negatively correlated with MAP.LPS also induced increases in H2S contents,CSE activity and the expression of mRNA in cardiac muscles and myocardial damages.Treatment with NaHS increased H2S contents in plasma,H2S contents and CSE activity in cardiac muscles,and aggravated the hypotensive action and tissue injuries caused by LPS administration（P0.05）.However,treatment with PPG reduced the increases in H2S contents in plasma,H2S contents and CSE activity in cardiac muscles,ameliorated the hypotensive effect and myocardial damages caused by LPS administration（P0.05）.Compared with normal control,LPS administration and LPS＋NaHS administration caused significant increase in the CSE expression mRNA in cardiac muscles,while the LPS＋ PPG administration were significantly decreased.Conclusion Endogenous hydrogen sulfide involves in the pathophysiological processes of endotoxic shock as a damaging factor,and the H2S / CSE system of myocardial tissue participates in the injuring of the myocardial tissue,at the same time,contributes to the heart failure.