Mild Hypothermia Combined With Isoflurane Posttreatment Alleviates Cerebral Ischemia Reperfusion Injury In Rats And The Influence Of The Expression Of STAT3

Objective: We conducted this study to assess the effect of mild hypothermia combined with isoflurane on cerebral ischemia reperfusion injury and p-STAT3 expression in rats and its possible mechanism.Methods: Fifty healthy adult male Sprague-Dawley rats were randomly divided into 5groups: Control group(Ctrl group),Model group(I/R group),Mild hypothermia(MH group),Isoflurane group(Iso group)and Mild hypothermia combined with isoflurane group(MH+Iso group).After 24 h reperfusion,neurological deficit scores were evaluated.Then,rats were sacrificed and five of them were used to detect infarct volume by TTC staining method.The other five served to measure protein levels of p-STAT3 and t-STAT3 by Western blotResults: Compared with I/R group,neurologic impairment score,volume of cerebral infarction and the value of p-STAT3/t-STAT3 in MH,Iso and MH+Iso groups were obviously decreased(P < 0.01).The express levels of phosphorylation level of JAK2 in post-treatment(MH,Iso and MH+Iso)groups were significantly lower than that in I/R group.Among the post-treatment groups,the neurologic impairment score was the lowest,volume of cerebral infarction,were maximum(P < 0.05)in MH+Iso group(P < 0.05).Conclusion: Mild hypothermia combined with isoflurane post-treatment can significantly reduce rat cerebral ischemia reperfusion injury,the effect is better than thatof mild hypothermia or isoflurane post-treatment alone.The mechanism may be that mild hypothermia combined with isoflurane post-treatment inhibited JAK2/STAT3 pathway in astrocytes or microglia,thereby inhibiting excessive activation of microglia and proliferation of astrocytes,and eventually they protected ischemic cerebral neurons from I/R injury.