Effect of hyperthermia and mild hypothermia on permeability of blood-brain barrier and its mechanism in rats with severe traumatic brain injury / 中华创伤杂志

ABSTRACT

Objective To investigate the effect of hyperthermia and mild hypothermia on permeability of blood-brain barrier(BBB),activity of matrix metalloproteinase-9(MMP-9)and expression of laminin in rats with severe traumatic brain injury(TBI)so as to explore the mechanism of hyperthermia and mild hypothermia affecting permeability of BBB. Methods A total of 72 healthy adult SpragueDawley rats were randomly divided into four groups,ie,sham operation group(SO group),TBI group,hyperthermia group(HT group)and mild hypothermia group(MH group).The rats were sacrificed at 24hours and the samples of injured brain tissues collected to detect the content of Evans blue(EB),activity of MMP-9 and expression of laminin. Results The content of EB and activity of MMP-9 in HT group were more significantly increased compared with those in TBI group(P<0.05),while the expression of laminin in HT group Was more significantly decreased than that in TBI group(P<0.05).However,the content of EB and activity of MMP-9 in MH group were significantly lower than those in TBI group(P<0.05),while the expression of laminin in MH group was significantly higher than that in TBI group(P<0.05). Conclusions The high activity of MMP-9 can.degrade laminin and increase permeability of BBB after TBI.After TBI,hyperthermia can increase permeability of BBB while mild hypothermia does on the contrary,which may be related to their different roles in changing activity of MMP-9.