Effects Of Mild Hypothermia On The Content Of Arginine Vasopressin In The Brain And Plasma Of Intracerebral Hemorrhage Rat

Abstract:Objective:The objective of the present study was to address the question of whether mild hypothermia play a role in brain edema and AVP content in different tissue of intracerebral hemorrhage rat, and whether mild hypothermia predicts brain protection in intracerebral hemorrhage rat. Explore hypothermia neuroprotective mechanism, Explore the possible mechanism of pathological damage in cerebral hemorrhage, further speculated that the relationship between the AVP content and brain edema. To determine whether the effect of mild hypothermia that inhibiting cerebral edema and reduce AVP content is associated with reduce body temperature.Therefore provide the basal evidences for hypothermia treatment in clinical. Methods:(1) Divide rat into different experimental groups:SD male rats of60, grouped by random number, divided into sham group, at room temperature cerebral hemorrhage group, mild hypothermia on cerebral hemorrhage group, n=20, each group was randomly divided into four group as6h,24h,72h,7days group,5rats in each subgroup.(2) Preparation of rat experimental model:room temperature and mild hypothermia group stereotactic brain autologous blood injection, injection of the50ul autologous blood to the caudate nucleus, the rat cerebral hemorrhage animal models, the surgery operating procedures of the sham-operated group with cerebral hemorrhage group, just do not injected autologous blood but normal saline.(3) the evaluation of the success of the model of intracerebral hemorrhage.(4) Mild hypothermia intervention:Mild hypothermia6h implementation of mild hypothermia intervention immediately after the injection of autologous blood, maintain hypothermia3h. Mild hypothermia at24h,72h,7d group were given mild hypothermia for3h everyday. The normothermia group maintain rectal temperature between36.5℃～37℃.(5) The neural score distribution form of model.(6) specimen collection and analysis, wet and dry method to measure brain water content and arginine vasopressin content measured by radio immunoassay.(7) statistical analysis the results of the of the data.Results:(1) neural function score:①normal cerebral hemorrhage were lower than the same time points in the sham operation group of nerve function score of mild hypothermia, cerebral hemorrhage group, the difference was significant (P<0.05).②The normal cerebral hemorrhage group at each time point in group72h neural function score was the lowest, compared with all other time points in the group with significant difference (P<0.05).③hypothermia hemorrhage group nerve function scores are higher than the same time point of the normal cerebral hemorrhage group, the difference was significant (P<0.05).(2) the water content of brain tissue of normal cerebral hemorrhage:①water content was higher than that of sham operation group at the same time, the group of brain tissue after cerebral hemorrhage, mild hypothermia group, the difference was significant (P<0.05).②The normal cerebral hemorrhage group at each time point in the brain tissue of72h group content is highest, compared with other each time point, the difference was significant (P<0.05).③Moisture content is reduced in24h,72h,7d than in normal temperature group of brain tissue in the mild hypothermia cerebral hemorrhage, the difference was significant (P<0.05).(3) arginine vasopressin contents:①normal cerebral hemorrhage of vasopressin levels were higher than those in the sham operation group at the same time, the group of brain tissue arginine hypothermia cerebral hemorrhage group, the difference was significant (P<0.05).②The normal cerebral hemorrhage group at each time point in group72h arginine vasopressin content was the highest, the difference was significant (P<0.05).③The mild hypothermia group rat cortex, thalamus, brainstem24h,72h,7d in brain tissue of arginine vasopressin content than normal group decreased, the difference was significant (P<0.05).④Pigment content and normal cerebral hemorrhage group was obviously lower pressure acid and mild hypothermia in cerebral hemorrhage group of plasma24h,72h arginine, the difference was significant (P<0.05).⑤Mild hypothermia group of arginine vasopressin content from cerebral hemorrhage after6h began to increase,24h increased significantly after24h, no significant difference of72h,7d decreased after. The AVP content higher than the cortex and brainstem, the difference was significant (P<0.05). Conclusion:(1)heart blood production SD rat caudate nucleus model of intracerebral hemorrhage is simple, accurate positioning quantitative, reproducible, high success rate of model.(2) cerebral hemorrhage, the rapid emergence of obvious damage to the pathophysiology of neurological dysfunction, brain edema, arginine vasopressin content was significantly higher.(3) cerebral hemorrhage after72hours of brain water content and arginine vasopressin content reached a peak, and then begin to decline, both the variable, then the correlation, indicating that arginine vasopressin may be involved in the occurrence of cerebral edema development, and plays an important role.(4) cerebral hemorrhage in the areas of the brain showed diffuse increased arginine vasopressin, which hypothalamic AVP content is highest, followed by the cortex, brainstem minimum. Plasma AVP levels increased, but is still significantly lower than the content in the brain tissue after intracerebral hemorrhage.(5) mild hypothermia on brain damage following cerebral hemorrhage have a significant role in mitigation, can reduce nerve dysfunction, reduced brain water content, and promote the recovery of neurological function and improve prognosis.(6) the protective effect of mild hypothermia on cerebral hemorrhage in addition to the mechanism to reduce brain metabolism, reduce cerebral blood flow, and inhibit the formation of excitatory amino acids, but also reducing the production and secretion and release of AVPin brain tissue, thereby inhibited brain edema, protected nerve function.