The changes of nuclear factor-κB expression in perihematoma region and brain edema of experimental in tracerebral hemorrhage rats after local mild to moderate hypothermia

Objective To investigate the effects of local mild to moderate hypothermia on brain edema and nuclear factor-κB (NF-κB) expression in the perihematoma region of experimental intracerebral hemorrhage rats.Methods A total of 144 Wistar rats were randomly divided into a normothermia group and a mild to moderate hypothermia group.The two groups each comprised control,6 h intracerebral hemorrhage,24 h intracerebral hemorrhage,48 h intracerebral hemorrhage,72 h intracerebral hemorrhage,and 1 week intracerebral hemorrhage subgroups,with 12 rats in each subgroup.Rat models of intracerebral hemorrhage were established by injection of autologous blood into the rat candate nucleus.Rats in the mild to moderate hypothermia group were subject to local mild to moderate hypothermia for 4 hours immediately after the injection,with the intracerebral temperature maintained at (33.0±0.5)℃,while those in the normothermia were maintained with a body temperature of 37℃.The changes of brain water content were measured and the expression of NF-κB in perihematoma region of intracerebral hemorrhage was observed with immunohistochemistry and Western blot methods. Results The brain edema and the NF-κB expression peaked at 48 h after intracerebral hemorrhage.There was obvious difference in terms of brain edema between the normothermia group and the mild to moderate hypothermia group (P＜0.05).The NF-κB expression reduced significandy in the mild to moderate hypothermia group compared with the normothermia group at the 24th,48th and 72nd hours,as well as 1 week after intracerebral hemorrhage (P＜0.05). Conclusions The severity of brain edema was associated with high expression of NF-κB.Treatment with local mild to moderate hypothermia can significantly inhibit overexpression of NF-κB and relieve brain edema following intracerebral hemorrhage. Key words: Intracerebral hemorrhage;  Brain edema;  Mild to moderate hypothermia;  Nuclear factor-κB