Effects And Mechanisms Of Hydrogen Sulfide On The Brain Injury After Cardiopulmonary Resuscitation

【Objective】1. To compare cardiac arrest induced by asphyxiation with cardiac arrest induced by transcutaneous electrical epicardium stimulation according to utstein style, and to find out a standardized animal cardiac arrest model which is consistant with clinical practice.2. To investigate the effects of hydrogen sulfide on the injury of brain injury induced by cardiac arrest.3. To investigate the effects of H2S on inflammatory reaction.4. To investigate the effects of H2S on apoptosis reaction.5. To investigate the effects of H2S on oxidative stress.6. To investigate whether the effects of H2S is associated with HIF-1.[Methods] In Part 1, animals were randomly divided into two groups:one group received cardiac arrest induced by asphyxiation, the other group received cardiac arrest induced by transcutaneous electrical epicardium stimulation. Animals were randomly divided into four groups:sham group, cardiopulmonary resuscitation group (CPR group), CPR+NaHS group and CPR+AOAA group. Types of cardiac arrest were observed, and time of asphyxiation or electrical stimulation to cardiac arrest were recorded. In Part 2,Part 3,Part 4, animals were randomly divided into four groups:The rats of sham group were only anesthetized and intubated. CPR group,NaHS+CPR group and CPR+AOAA group received cardiac arrest by transcutaneous electrical epicardium stimulation. For CPR+NaHS group, NaHS (100ug/kg) was administrated via the femoral venous line 1 minute before CPR. For CPR+AOAA group, AOAA (20mg/kg) was administrated via the femoral venous line 1 minute before CPR. NDS value was scored and the morphological structures of brain were also observed. TNF-a and IL-1βwere detected by ELISA method; Bax and Bcl-2 expression were detected by PCR and immunohistochemical methods; MDA and SOD were determined; the expression of HIF-1 were also determined by real-time quantitative PCR and Western blot.[Results] Cardiac arrest induced by transcutaneous electrical epicardium stimulation appeared VF, PEA, asytole. Cardiac arrest induced by asphyxiation appeared PEA, asytole. Time of asphyxiation to cardiac arrest was obviously longer than electrical stimulation to cardiac arrest(p＜0.05). Compared with sham group, the concentration of TNF-a were substantially elevated at 3h,6h,9h,12h(p<0.05), and it peaked 6h after CPR; Compared with CPR, the concentrations of TNF-a in CPR+NaHS were substantially decreased at 3h, 6h,9h,12h(p＜0.05), the concentrations of TNF-a in CPR+AOAA were substantially increased at 3h,6h(p＜0.05). Compared with sham group, the concentration of IL-1βwere substantially elevated at 3h,6h,9h,12h(p＜0.05), and it peaked 6h after CPR; Compared with CPR, the concentrations of IL-1βin CPR+NaHS were substantially decreased at 6h, 9h,12h(p＜0.05), the concentrations of TNF-a in CPR+AOAA were substantially increased at 3h,6h,9h(p＜0.05). Compared with sham group, the expression of Bax in CPR was increased(p＜0.05); Compared with CPR, the expression of Bax in CPR+NaHS group was decreased(p＜0.05); There were no obviously differences in CPR group and CPR+AOAA group. Compared with sham group, the expression of Bcl-2 in CPR was increased(p＞0.05); Compared with CPR, the expression of Bcl-2 in CPR+NaHS was obviously increased(p＜0.05); and the expression of Bcl-2 in CPR+AOAA was obviously decreased(p＜0.05). Compared with sham group, the ratio of Bax/Bcl-2 in CPR was increased(p＜0.05); Compared with CPR, the ratio of Bax/Bcl-2 in CPR+NaHS group was decreased(p＜0.05); and the ratio of Bax/Bcl-2 in CPR+AOAA group was increased(p＜0.05). Compared with sham group, the expression of SOD in CPR was decreased(p＜0.05); Compared with CPR, the expression of SOD in CPR+NaHS was obviously increased(p＜0.05); and the expression of SOD in CPR+AOAA was obviously decreased(p＜0.05). Compared with sham group, the expression of MDA in CPR was increased(p＜0.05); Compared with CPR, the expression of MDA in CPR+NaHS was obviously decreased(p＜0.05); and the expression of MDA in CPR+AOAA was obviously increased(p＜0.05). Compared with sham group, the expression of HIF-1 gene and protein was upregulated. Compared with CPR group, the expression of HIF-1 gene and protein in CPR+NaHS group was upregulated, and the expression of HIF-1 gene and protein in CPR+AOAA group has a lower trend(p＜0.05).[Conclusion] The cardiac arrest model induced by transcutaneous electrical epicardium stimulation is more close to clinical practice, the standardization of model is superior to cardiac arrest induced by asphyxiation. Hydrogen sulfide can protect brain from injury, and administration of AOAA aggravated brain damage. The mechanism is associated with antiinflammation, relieving apoptosis, reducing oxidatie stress reaction relevant and upregualating HIF-1.