Effect Of Therapeutic Hypothermia Combined With Hydrogen Sulfide On Hippocampal Endoplasmic Reticulum Stress After Cardiopulmonary Resuscitation

Cardiopulmonary resuscitation(CPR)technology has saved countless lives of cardiac arrest patients since 1960s,with the develpment of CPR,the survival rate of patients after cardiac arrest has been significantly improved.However,the brain ischemia starts within minutes after cardiac arrest,and the structural damage and dysfunction of the ischemic brain area would be further aggravated owning to ischemia reperfusion(I/R)injury.Therefore,many patients with cardiac arrest have serious neurological dysfunction even if they are rescued effectively,which will bring serious psychological and economic burden to families and society.So lots of studies have been made in the treatment of cerebral resuscitation after CPR considering its important social significance and research value in recent years.At present,therapeutic hypothermia(TH)is the most effective method in brain resuscitation,and is widely used in clinical practice.A number of clinical and basic studies have shown that hypothermia treatment after cardiopulmonary resuscitation could reduce brain oxygen consumption and energy metabolism,mitigate cell acidosis and reduce the production of reactive oxygen species and excitatory amino acids,reducing the production of inflammatory factors and affecting multiple apoptosis related molecular pathways.Death receptor pathway and mitochondrial pathway are two classical pathways of neuronal apoptosis,In recent years,scientists have proposed the third pathways to induce apoptosis,that is,the endoplasmic reticulum stress(ERS)pathway.According to our previous studies,we found that therapeutic hypothermia could alleviate endoplasmic reticulum stress in hippocampus of rats with global cerebral ischemia-reperfusion and decrease the apoptotic rate of neurons.However,the effect of pure therapeutic hypothermia on cerebral resuscitation in rats is limited,so more and more researchers are seeking a combination of drugs to improve the curative effect of cerebral resuscitation.It has been found that exogenous supplementation of H2S can reduce oxidative stress and apoptosis in cerebral ischemia reperfusion injury.Therefore,the aim of this study is to explore the effect of hydrogen sulfide alone on hippocampal endoplasmic reticulum stress and the effect of combined therapeutic hypothermia on hippocampal endoplasmic reticulum stress in a rat model of global cerebral ischemia-reperfusion injury.Part ? Effect of hydrogen sulfide on hippocampal endoplasmic reticulum stress after cardiopulmonary resuscitation in ratsObjective:To evaluate the effect of hydrogen sulfide on hippocampal endoplasmic reticulum stress after cardiopulmonary resuscitation in rats.Methods:Ninety-six healthy male Sprague-Dawley rats,weighing 280?320 g,8?10 week old,were randomly divided into 4 groups(n=24 each)using a random number table:sham operation group(group Sham),hydrogen sulfide group(group H2S),global cerebral I/R group(group I/R),and global cerebral I/R+ hydrogen sulfide(group I/R+H2S).Cardiac arrest was induced with transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I/R model.No cardiac arrest and cardiopulmonary resuscitation in group Sham and group H2S.Sodium hydrosulfide was intraperitoneal injection as a bolus of 2.5 mg/kg immediately restoration of spontaneous circulation in group H2S and group I/R+H2S,intraperitoneal injection of equal amount of normal saline in group Sham and group I/R.The hippocampal tissue were immediately removed at 24 h after reperfusion,the expression of glucose-regulated protein 78(GRP78),CHOP and Caspase-12 were detected by Western blot;After reperfusion 1 d,3 d and 7 d,the hippocampal tissue were removed and stained with haematoxylin and eosin to examine the pathological findings in hippocampal CAl area.TUNEL staining was used to detect the apoptosis of hippocampal neurons,calculation the apoptosis rate.Results:There was no statistically differences between Sham group and H2S group(P>0.05);Compared with Sham group or H2S group,the expression of GRP78,CHOP and Caspase-12 in the I/R group and the I/R+H2S group were increased,normal vertebral cell reduced and the number of apoptotic cells increased(P<0.05);Compared with I/R group,the expression of GRP78(0.30±0.01 vs 0.22±0.01,P<0.05),CHOP(1.02±0.01 vs 0.81±0.02,P<0.05)and Caspase-12(0.48±0.02 vs 0.37±0.04,P<0.05)in the I/R+NaHS group were decreased,normal vertebral cell increased and the number of apoptotic cells decreased(1 d,6.0±1.8 vs 3.3±1.2;3 d,49.5±1.9 vs 29.8±2.2;7 d,47.5±2.7 vs 28.7±2.2,all P<0.05).Conclusion:The mechanism of hydrogen sulfide decrease the apoptosis of hippocampal cells in rats with cardiopulmonary resuscitation is related to the inhibition of endoplasmic reticulum stress.Part ? Therapeutic hypothermia combined with hydrogen sulfide alleviates hippocampal endoplasmic reticulum stress after cardiopulmonary resuscitationObjective:To investigate the effect of therapeutic hypothermia combined with hydrogen sulfide on hippocampal endoplasmic reticulum stress after cardiopulmonary resuscitation.Methods:Two hundred and twenty healthy male Sprague-Dawley rats,weighing 280?320 g,8?10 week old,were randomly divided into 5 groups(n=44 each,1 d group 12;3 d group 12;7 d group 20)using a random number table:sham operation group(group Sham),global cerebral I/R group(group I/R),hydrogen sulfide group(group I/R+H2S),therapeutic hypothermia group(group I/R+TH)and hydrogen sulfide+therapeutic hypothermia group(group I/R+H2S+TH).Cardiac arrest was induced with transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I/R model.7d group(20 rats)at reperfusion 1 d,3 d and 7 d were neurological deficit score(Neurological Deficit Scores,NDS)and recorded the survival situation.6 rats in each group were sacrificed to get the hippocampal tissue,the expression of glucose-regulated protein 78(GRP78),CHOP and Caspase-12 were detected by Western blot.The hippocampal tissues were taken from 6 rats in each group at 1 d,3 d and 7 d reperfusion,the hippocampal tissue were removed and stained with haematoxylin and eosin to examine the pathological findings in hippocampal CA1 area.TUNEL staining was used to detect the apoptosis of hippocampal neurons,calculation the apoptosis rate.Results:Compared with group Sham,the expression of GRP78,CHOP and Caspase-12 in the other groups increased significantly at 1 d,3 d and 7 d after reperfusion.Compared with the I/R group,the expressions of GRP78,CHOP and Caspase-12 in group I/R+H2S and group I/R+TH were decreased,and the difference was statistically significant.The most obvious in the case of reperfusion 3d,[GRP78:(1.11±0.10)vs(0.67±0.09?0.66±0.08?0.48±0.04,all P<0.05);CHOP:(1.60±0.11)vs(1.39±0.09?1.34±0.08?1.13±0.09),all P<0.05;Caspase-12:(0.87±0.08)vs(0.65±0.08?0.59±0.06?0.45±0.06),all P<0.05)].Reperfusion at 3 d and 7 d,compared with group Sham,the pathological damage of the hippocampal CA1 area was serious,the rate of apoptosis increased,and the score of nerve function defect was reduced.Compared with group I/R,I/R+H2S group and I/R+TH group I/R+H2S+TH group showed hippocampal CA1 area pathological damage reduced,cell apoptosis rate decreased,neurological function score increased,the difference was statistically significant.In addition to group Sham,the apoptosis rate of 3 d and 7 d in each group was significantly higher than that of 1 d,and the score of neurological deficit of 3 d and 7 d was obviously improved than 1 d,In group I/R+H2S+TH,the rate of apoptosis was the lowest,and the improvement of neurological deficit score was the most obvious.The 7 natural survival rate of group I/R+H2S+TH was significantly better than that in group I/R,I/R+H2S group and I/R+TH group,and the difference was statistically significant.Treatment alone or combined with therapeutic temperature and hydrogen sulfide can significantly improve the endoplasmic reticulum stress response,reduce pathological damage,reduce cell apoptosis rate,improve neurological deficit score,and increase the 7 natural survival rate.Conclusion:Therapeutic hypothermia combined with hydrogen sulfide alleviates hippocampal endoplasmic reticulum stress after cardiopulmonary resuscitation,and the combined effect is better than that of a single application.Conclusion1.Cerebral ischemia-reperfusion injury after cardiac arrest can stimulate the overexpression of endoplasmic reticulum stress related proteins,cell damage in the CA1 region of the hippocampus and apoptosis of nerve cells,exogenous hydrogen sulfide can reduce the apoptosis of hippocampal cells after cardiopulmonary resuscitation in rats,and the mechanism is related to the inhibition of endoplasmic reticulum stress.2.Therapeutic hypothermia can effectively reduce the overexpression of endoplasmic reticulum stress related proteins after cardiopulmonary resuscitation,reduce neuron apoptosis,improve the prognosis of nerve function,and increase the 7 natural survival rate,the combination of hydrogen sulfide have the best effect on cerebral resuscitation.