Study Of Change Of Blood-brain Barrier Permeability Following Traumatic Brain Injury In Rats Exposed Under Cold Environment

Objective：To study the change of blood-brain barrier（BBB） permeability and theendogenous IgG leak of expression following traumatic brain injury in rats exposedunder cold environment. Explored the impact of the cold environment of theblood-brain barrier after brain injury, provided the experiment theoretical guidingsignificance for the clinical care traumatic brain injury.Methods：Healthy Sprague-Dawley rats (male or female), weighing250-350g, wererandomly divided into normal temperature control group (n=20), cold environmentcontrol group (n=20), cold environment post-traumatic group (n=20), commontemperature post-traumatic group (n=20).Each group was further specimens timeafter traumatic brain injury breakage is divided into four subgroups, respectively, for1day、3days、5days、7days,5rats in each subgroup. Improved Feeney’s freefalling body epidural strike method was used to cause traumatic brain injury in ratsexposed under cold environment. The change of the opening state of tight junctionwere observed using lanthanum trace labeling with electron microscope,dry-wetweight method to calculate changes in water content of cerebral tissue, and usedimmune-ohistochemical method to detect endogenous IgG exudation of expression.Results:1. Changes of Lanthanum permeability: The lanthanum did not permeate to theoutside of blood-vessel in common temperature control group、cold environmentcontrol group. Vascular endothelial cells did not damage. The lanthanum obviouslypermeated to the outside of blood-vessel in common temperature post-traumaticgroup and cold environment post-traumatic group at the same time. But the number ofthe penetration were more in cold environment post-traumatic group than incommon temperature post-traumatic group（P<0.05）． 2. Changes of brain water content:In common temperature post-traumatic groupand cold environment post-traumatic group, the brain water content increased andreached the peak in the first day and three days, at five days and seven days graduallyreduced, the cold environment post-traumatic group than the common temperaturepost-traumatic group compared brain water content was significantly increased at onedays、hree days、five days,and there was statistically significant (P <0.05).7days ofbrain water content increased the amount was not obvious, and no significantdifference (P>0.05).3. Expression changes of IgG: In common temperature post-traumatic group andcold environment post-traumatic group, endogenous IgG exudation increased andreached the peak in the first day and three days, at each time point, the coldenvironment post-traumatic group compared with common temperature post-traumatic group, the endogenous IgG exudation significantly increased, there wasstatistically significant (P <0.05).Conclusions：1. After traumatic brain injury blood brain barrier failure mechanism is due toincreased the opening state of tight junction of vascular endothelial cells.2.Traumatic brain injury exposed under cold environment, blood-brain barrierpermeability reached a peak in the first day and three days, at five days graduallyreduced.3.Traumatic Brain Injury in4℃cold environment could increase the braintissue of water,the endogenous IgG exudation and the permeability of lanthanum,promoted the opening of the tight junction.