Effects of mild hypothermia on the expression of HSP70 protein and HSP70 mRNA and the cell apoptosis at CA3 area of hippocampus in rats after diffuse brain injury

Objective To observe the effects of mild hypothermia on the expression of HSP70 protein and HSP70 mRNA and the cell apoptosis at CA3 area ofhippocampus in rats following experimental diffuse brain injury (DBI) and to explore the neuroprotective mechanism of mild hypothermia at molecular level. Methods The rats were divided into four groups: control, pseudo-operation, only DBI and post-DBl mild hypothermia treatment. Marmarou' s method was used to establish the animal model of DBI. Immunohistochemistry, RT-PCR and flow cytometer were separatively performed to examine the expression of HSP70 at protein and mRNA level and the cell apoptotic rate at CA3 area of hippocampus in each group. Results Compared to the control group, both the HSPT0 expression at protein and mRNA level and cell apoptotic ratio at CA3 area of hippocampus in rat brain increased following DBI (P0.05). When the rats subjected to DBI were treated with the mild hypothermia, the HSP70 expression at protein and mRNA level significantly increased (P0.01) in hippocampus CA3 area of rat brain, while the cell apoptosis rate decreased (P0.05). Conclusion The neuroprotective effects of mild hypothermia on the traumatic brain injury may be correlated with the improvement of liSP70 protein and HSP70 mRNA expression as well as the decrease of the cell apoptosis in the injuryed brain tissue.