Objective To determine the effect of hypothermia on gene transcription and protein expression of calpain after traumatic brain injury (TBI). Methods Twenty-seven rats were randomly divided into three groups, ie, normal control group, normothermia TBI group and hypothermia TBI group. All rats with TBI were suffered from a lateral fluid percussion injury (FPI) at the right parietal lobe. Hy-pothermia intervention [rectal temperature for (32 ± 0.5) ℃] was performed for four hours immediately after TBI in hypothermia TBI group. Fluorescence PCR and Western blot were utilized to semi-quantify gene transcription and protein expression of ealpain and immunofluorescence used to observe protein dis-tribution of Calpain. Results Compared with normothermia TBi group and normal control group, hypo-thermia TBI group showed increased calpain gene transcription at 12 and 24 hours respectively after FPI (P <0.05). However, the increase of ealpain protein expression in hypothermia TBI group was inhibited more significantly by hypothermia at 6,12,24 and 72 hours after TBI, compared with normothermia TBI group (P < 0.05). Conclusion Neuroproteetion of hypothermia after TBI may somewhat be related to the decrease of calpain protein expression after its gene transcription.

Objective To investigate the mRNA and protein expressions of Nav 1.1 and Nav 1.2 in hippocampus following traumatic brain injury ( TBI) in rats.Methods After the lateral fluid percussion model was established in adult male Sprague Dawley rats,the rats were sacrificed at 2,12,24 and 72 hours after percussion and collected ipsilateral hippocampus for detecting mRNA and protein expressions of Nav 1.1 and Nav 1.2 by means of fluorescent quantitation RT-PCR,Western blot and immunofluo rescence staining.Results The mRNA expressions of Nav 1.1 and Nav 1.2 were significantly down-regulated (P<0.01) in hippocampus and reached the lowest level at 2 hours following TBI.The protein expression of Nav 1.1 was significantly down-regulated (P<0.01) but recovered near to level of control group at 72 hours after TBI.While there was no statistical difference on protein expression of Nav 1.2 in hippocampus after TBI compared with control group (P>0.05).Conclusion TBI induces significant down-regulated mRNA and protein expressions of Nav 1.1 in the hippocampus,which may be one of molecular mechanisms for functional alternation of sodium channels and excitotoxic action following TBI.