| Background:Hypoxic-ischemic brain injury(HIBI)is the main cause of death after resuscitation of cardiac arrest(CA).With the improvement of medical technology,the recovery rate of autonomic circulation after CA can exceed 50%,but the final discharge rate is less than 10%.It has been found that mild hypothermia plays a neuroprotective role by inhibiting apoptosis,reducing the production of excitatory toxins and free radicals,and anti-inflammatory effects.Hydrogen has also been shown to protect the brain and significantly improve its prognosis.However,there is no experimental mechanism for the combination of the two.This study explored the possible mechanism of the protective effect of mild hypothermia combined with hydrogen inhalation on the cardio cerebral function of asphyxiated rabbits after resuscitation.Purposes:The aim of this study was to investigate the protective effect of mild hypothermia combined with hydrogen inhalation on brain function after resuscitation in rabbits with extracorporeal shock induced fibrillation.Methods:50 adult healthy rabbits were fed adaptively for one week,and randomly divided into normal control group(group A),conventional resuscitation group(group B),mild hypothermia resuscitation group(group C),inhalation hydrogen resuscitation group(group D),mild hypothermia combined inhalation hydrogen resuscitation group(group E),10 in each group.In group A,only tracheal intubation and arteriovenous intubation were performed without electric shock.In group B,adrenaline(0.02 mg / kg)was used for routine cardiopulmonary resuscitation;in group C,alcohol jet and ice bag fan were used for surface physical cooling after ROSC.The esophageal temperature of rabbits dropped to 33 ℃ left and right about 10 minutes after cardiopulmonary resuscitation,maintained for 2 hours,and recovered to normal temperature after 2 hours;in group D,mechanical ventilation was used for 2% hydrogen + 98% oxygen The temperature of esophagus in Group E decreased to 33 ℃ by conventional physical cooling method about 10 minutes after resuscitation,2% hydrogen + 98% oxygen ventilation for 1 hour,maintained a mild hypothermia for 1 hour,and returned to normal after 2 hours.Each group was killed 15 minutes before ventricular fibrillation,1 hour,6 hours,12 hours and 24 hours after ROSC.Serum and brain tissue of rabbits were taken,NSE,S-100 β protein and Caspase-3 concentrations in serum were measured,and brain water content was measured.Results:(1)Serum concentrations of NSE,S-100 β and caspase-3: the results showed that there was no significant difference between group B,group C,group D and group E(P > 0.05);the concentrations of serum NSE,S-100 β and Caspase-3 in group B were significantly higher than those in group A(P < 0.05);The brain water content in group B was significantly higher than that in group A(P < 0.05),indicating that the experimental model was successful(see Table 1,table 2 and table 3 for details).(2)Compared with group A,the concentrations of NSE in groups B,C,D and e increased at 1 h,6 h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05).Compared with group B,NSE concentration in groups C,D and e decreased at 6h,12 h and 24 h after recovery of spontaneous circulation(P < 0.05).The concentration of NSE in Group E was lower than that in group C and D at 6h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05),while the concentration of NSE in group D was lower than that in group C at 6h,12 h and 24h(P < 0.05).(3)Compared with group A,the concentration of S-100 β in groups B,C,D and e increased at 1 h,6 h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05).Compared with group B,NSE concentration in groups C,D and e decreased at 6h,12 h and 24 h after recovery of spontaneous circulation(P < 0.05).The concentration of NSE in Group E was lower than that in group C and D at 6h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05),while the concentration of NSE in group D was lower than that in group C at 6h,12 h and 24h(P < 0.05).(4)Compared with group A,the concentration of Caspase-3 in groups B,C,D and e increased at 1 h,6 h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05).Compared with group B,NSE concentration in groups C,D and e decreased at 6h,12 h and 24 h after recovery of spontaneous circulation(P < 0.05).The concentration of NSE in Group E was lower than that in group C and group D at 6h,12 h and 24 h after the recovery of spontaneous circulation(P < 0.05),while the concentration of NSE in group D was lower than that in group C at 6h,12 h and 24h(P < 0.05)(5)Brain water content: the brain water content in group A was significantly higher than that in group B(P < 0.05).C.The brain water content of group D and E was lower than that of group B(P < 0.05);the brain water content of group E was lower than that of group C and D(P < 0.05);the brain water content of group D was lower than that of group C(P < 0.05)Conclusion:Mild hypothermia and inhalation of hydrogen have protective effects on the function of brain after CA. |
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