Effect Of Hypothermia And Magnesium Sulfate Treatment On The Rats’ Neuron Apoptosis After Cardiopulmonary Resuscitation By Asphyxia Method

PartⅠEffect of Hypothermia and Magnesium Sulfate Treatment onneurological function and morphological changes after CardiopulmonaryResuscitation in ratsObjective: To evaluate the effect of Hypothermia and Magnesium Sulfate Treatmenton neurological function after cardiopulmonary resuscitation, and to observe neuronalapoptosis in rats at the24th hour after restoration of spontaneous circulation by AsphyxiaMethod.Methods: Forty-six male SD rats were randomly divided into five groups: controlgroup, normothermic group, mild hypothermia group, magnesium sulfate group and mildhypothermia combines magnesium sulfate group. Each group was10except the controlgroup was6. The cardiac arrest model in rats was duplicated by Asphyxia method. Toobserve the time of ROSC、the percentage of successful resuscitation、the percentage ofsurvival on24th hour after ROSC and Neuro Deficit Score, transmission electronmicroscope(TEM)was used to observe the morphological changes.Results:1. There were significant differences in NDS level between resuscitationgroups and control group (P<0.01), but there were no significant difference amongresuscitation groups (P>0.05).2. TEM Observation: Compared with the control group, theresuscitative group was detected that apoptosis appeared in nerve cell、neuralgia cell、myelin sheath. Compared with the normothermic group, the mild hypothermia group、themagnesium sulfate group and especially the mild hypothermia and magnesium sulfate group had the apoptosis reduced。Conclusion:1. The neurological function were severely impaired in rats aftercardiopulmonary resuscitation.2. Mild hypothermia and Magnesium Sulfate Treatmentcan reduce neuronal apoptosis. PartⅡ Effect of mild hypothermia and Magnesium Sulfate Treatment onthe expression level of caspase-3mRNA and bcl-2mRNA in rat’shippocampusObjective: To explore the effect and the mechanism of mild hypothermia andmagnesium sulfate treatment on the neuron apoptosis in rats after cardiopulmonaryresuscitation．Methods: Seventy-eight male SD rats were randomly divided into five groups:control group (n=6), normothermic group, mild hypothermia group, magnesium sulfategroup and mild hypothermia combining magnesium sulfate group. The later four groupswere again divided into three subgroups: ROSC6,12and24hours groups (each subgroupn=6). The cardiac arrest model in rats was duplicated by Asphyxia method. To evaluateNeuro Deficit Score at corresponding time. The expression of caspase-3and bcl-2mRNAexpression level in brain tissue was measured by RT-PCR.Results:1. Compared with that in the control group, the caspase-3expression wereincreased significantly (P＜0.01) in the resuscitation group. Compared with that in thenormothermic group, the expression of caspase-3mRNA were reduced significantly (P＜0.05) in the mild hypothermia group, the magnesium sulfate group and the mildhypothermia combining magnesium sulfate group. The expression level ofcaspase-3mRNA in the mild hypothermia and magnesium sulfate group was lower than that of the mild hypothermia group and the magnesium sulfate group (P＜0.05)．2. Theexpression level of bcl-2mRNA in the resuscitation groups were higher than the controlgroup (P＜0.01). There were no significances among the resuscitation groups.3. Therewere significant differences in NDS level between the resuscitation groups and the controlgroup, but there were no significant difference among the resuscitation groups.Conclusion:1. The mild hypothermia and magnesium sulfate can inhibit theapoptosis by reducing the expression of aspase-3mRNA, so it has protective effect to thebrain injuries.2. Mild hypothermia and magnesium sulfate can significantly reduce theexpression of apoptosis gene; Mild hypothermia and magnesium sulfate have developedsynergism effect.