Moderate hypothermia alters interleukin-6 and interleukin-1α reactions in ischemic brain in mice

Female C57BL/6 mice were decapitated and their brains were removed and cultured at either 37 or 33 degreesC for 48 h to investigate whether or not moderate hypothermia alters the cytokine reactions in the ischemic brain. The interleukin-6 and interleukin-la levels in the Culture media were significantly elevated in a time-dependent manner. The interleukin-6 levels after the incubation at 33 degreesC were significantly lower than those at 37 degreesC. The interleukin-la levels at 33 degreesC were significantly higher than those at 37 degreesC. The interteukin-1alpha levels incubated with interteukin-6 antibody were significantly higher than those without IL-6 antibody. At 37 degreesC, the mRNA expression of interleukin-6 was observed from 2 to 48 h after incubation, but the same expression of interleukin-1alpha was only detected until 12 h. Accordingly, the ischemic brain incubated at 33 degreesC showed a decreased interleukin-6 production in comparison with that at 37 degreesC and the level of interieukin-6 showed negative feedback for the production of interleukin-la. The temperature should, therefore, be carefully considered when evaluating the cytokine reaction for cerebral ischemia. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.