| Cardiac arrest(CA)is caused by a sudden stop of heartbeat in vario us causes and loss of effective pump function.It is one of the most com mon and most critical emergencies in clinical practice.Restoring brain fun ction is the focus of resuscitation research.The mechanism of cerebral isc hemia-reperfusion injury after CA and CPR is complex.After CA,the pu mping function of the heart suddenly stops,leading to interruption of blo od supply to the brain and vital organs.Over time,serious problems will occur.Irreversible brain injury or even death,timely high-quality cardiop ulmonary resuscitation(CPR)is the key to improve survival after cardiac arrest,although the development and widespread use of cardiopulmonary r esuscitation has saved more and more patients.While reducing the disabili ty rate,more severe brain injury occurs after Restoration of spontaneous c irculation(ROSC).related to ischemia/reperfution injury.A large number o f studies have shown that calcium overload plays an important role in ischemia-reperfusion injury.Finding effective neuroprotective drugs for ische mia-reperfusion injury and promoting neurological recovery is still a hot t opic in current resuscitation research.Magnesium sulfate has the effects of antagonizing calcium ion,reducing oxygen free radicals,and relieving ce rebral vasospasm.It is widely used in the treatment of stroke,and has th e effects of cerebral ischemia reperfusion injury and focal cerebral ischem ia-reperfusion injury caused by CA and CPR.Similar pathogenesis,whethe r magnesium sulfate has the same brain protection after resuscitation is no t clear,so design this experiment.In this study,a rat model of CA was i nduced by esophageal pacing to induce ventricular fibrillation,and then di fferent doses of magnesium sulphate were administered to the rats after re suscitation.The effects of magnesium sulfate on brain protection in CA/C PR rats were studied.The study consisted of two parts: In the first part,magnesium sulfate was used immediately after resuscitation.The effect of magnesium sulfate on survival time,survival rate and neurological functi on of rats after resuscitation was observed.The second part was to detect brain tissue nitric oxide(NO).Content and total nitric oxide synthase(TNOS),inducible NOS(i NOS)activity,sodium-potassium-ATPase,calciummagnesium-ATPase activity,Western Blot determination of brain tissue apo ptosis protein Bax,Bcl-2 expression Investigate the possible mechanisms o f antioxidant activity,ATPase activity,and neuronal apoptosis.Method:1.Total of 120 healthy SD rats weighing 250-300 g were randomly divided into 5 groups: sham operation group(n=24),saline group(n=24),and magnesium sulfate group(=72);The magnesium components were high,medium,and low dose groups.Rats in saline group and magnesium sulfategroup were induced by esophageal pacing to induce CA of ventricular fibrillation.After 5 min,chest compressions were given.After recovery of spontaneous circulation,saline or magnesium sulfate was intraperitoneally injected.Continuous monitoring of hemodynamic changes in rats.The rats in the sham-operated group were operated only and did not induce CA.The survival time and survival rate of the rats in each group were compared.Neurological deficit scores(NDS)were also performed at the corresponding time points.2.SD rats weighing 180-250 g were randomly divided into four groups:sham operation group,model group,magnesium sulfate medium dose group,magnesium sulfate high dose group,with 16 rats in each group.After trans esophageal cardiac pacing method was successfully established,it was placed in a cage and was sacrificed 24 hours after ROSC.The brain tissue was taken to detect the content of nitric oxide(NO)and total nitric oxide synthase(T-NOS)in brain tissue.The activities of inducible NOS(i NOS),sodium-potassium-ATPase,and calcium-magnesium-ATPase were determined.The expression of Bax and Bcl-2 in brain tissue was determined by Western Blot.Results:1.The survival time of the magnesium sulfate group was significantly longer than that of the saline group(p<0.05).;high-dose magnesium sulfate group and medium dose magnesium group were 12 h,24h,48 h,72-hour survival rate was significantly better than the latter two groups(p<0.05),but there was no significant difference between the high-dose group and the medium-dose group,the low-dose group and the saline group(p>0.05),and the rats in the saline group were each The NDS scores at the time points were lower than those in the magnesium sulfate group(p<0.05).2.The content of NO,activity of NOS and i NOS in saline group weresignificantly higher than those in sham group and Mg SO4 group(p<0.05).The activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in brain tissues were higher in sham group and Mg SO4 group than in saline(p<0.05).Compared with the sham group,Bax expression in the brain tissue of the model group increased(p<0.05),Bcl-2 expression decreased(p<0.05);compared with the model group,Mg SO4 groups inhibited Bax expression in the brain(p <0.05),Bcl-2 protein expression was significantly increased(p<0.05).Conclusion:1.Magnesium sulfate can prolong the survival time of rats after CPR,improve survival rate and improve nervous system function;2.Magnesium sulfate was given immediately after cardiopulmonary resuscitation in rats,which can reduce the degree of brain injury and reduce apoptosis. |
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