Protective Effect Of Hypoxic Preconditioning And Sevoflurane Preconditioning On Transient Global Cerebral Ischemia In Adult Rats Via Regulating The Expression Of Jun-B MRNA

Objective: To observe the protective effects of hypoxic preconditioning and sevoflurane preconditioning on transient total cerebral ischemia(tGCI)in adult rats and their effects on the expression of Jun-B mRNA.Methods: Adult healthy male rats(Sprague Dawley,SD)were randomly divided into four groups: Transient global cerebral ischemia group(tGCI group),Hypoxic preconditioning group(Hypoxic preconditioning group,HPC group)Sevoflurane(SEV group),Hypoxic + Sevoflurane preconditioning group(H+S group),twelve rats per group.tGCI group: the 10 min tGCI rat model was established by Pulsinelli four-vessel occlusion method(4VO).HPC group: repeated exposure to the decompression chamber at simulated altitude of 4000 m,one hour a day for five days.SEV group: rats were pretreated with 2.4% sevoflurane mixed with 100% oxygen,one hour a day for five days.H+S group: hypoxic pretreatment combined with sevoflurane pretreatment,one hour a day for five days.Ischemia-reperfusion four hours(T1),twenty-four hours(T2),seven days(T3)rats were executed,hippocampus frozen section,(Fluoro-Jade B,FJB)fluorescence staining,observed hippocampus nerve apoptosis,hippocampal tissue RNA extracted by Trizol and q PCR method were used to detect the analysis of Jun-B mRNA in hippocampus relative expression level,finally using the statistical software for data analysis.Results:(1)FJB fluorescence staining results: compared with tGCI group,the number of FJB positive cells in HPC group,SEV group and H+S group decreased significantly at time points T1,T2 and T3(P < 0.01).Compared with the HPC group,the number of FJB positive cells in the H+S group decreased significantly at time points T1,T2 and T3(P < 0.05).Comparison between the H+S group and the SEV group: there was no significant change in the number of FJB positive cells at T1 and T2 time points,with no significant difference(P > 0.05).At T3 time points,the number of FJB positive cells in the H+S group was significantly reduced,with significant difference(P < 0.05).(2)q PCR results: compared with tGCI group,HPC group,SEV group and H+S group,the relative expression levels of Jun-B mRNA in HPC group,SEV group and H+S group were significantly reduced at T1,T2 and T3 time points,with significant differences(P < 0.01).Comparison between the H+S group and the HPC group: at time points T1,T2 and T3,the relative expression of Jun-B mRNA in the H+S group decreased significantly(P < 0.05).Comparison between the H+S group and the SEV group: at T1 and T2 time points,the relative expression of Jun-B mRNA in the H+S group decreased significantly(P < 0.05).At T3 time points,there was no significant change in the relative expression of Jun-B mRNA in the H+S group(P > 0.05).Conclusion:(1)Hypoxic preconditioning,sevoflurane preconditioning and hypoxic preconditioning plus sevoflurane preconditioning all had protective effects on nerve cells of hippocampal tissue after tGCI rat model,and the protective effects of hypoxic preconditioning plus sevoflurane preconditioning may be stronger than that of hypoxic preconditioning and sevoflurane preconditioning;(2)The protective effect of hypoxic pretreatment and sevoflurane pretreatment on neurons in hippocampal tissue after tGCI rat model may be due to the regulation of Jun-B mRNA expression.