应激剂量氢化可的松对颅脑外伤后危重症相关皮质类固醇不足治疗作用的实验研究

摘要

目的 研究颅脑外伤(TBI)后早期应激剂量氢化可的松(HC)对危重症相关皮质类固醇不足(CIRCI)的治疗作用.方法 利用成年雄性Wistar大鼠建立液压打击TBI模型,在伤后第1天通过电应激刺激筛选出CIRCI大鼠.将CRICI大鼠随机分为CIRCI对照组、小剂量甲泼尼龙(MP)治疗组、应激剂量HC治疗组,分别于伤后第1、3、7及14天进行神经功能评分比较三组的神经功能障碍程度,并于伤后14 d内考查各组大鼠存活率;伤后第7天和第14天分别进行电应激刺激,比较三组大鼠的CIRCI患病率.分别于伤后第3、7及14天对三组大鼠进行下丘脑组织病理学观察.采用CD31和Claudin 5免疫荧光染色法比较室旁核区血脑屏障内皮细胞及紧密连接改变的差异,结合伊文思蓝染色检测该部位的血脑屏障通透性.结果 应激剂量HC治疗组大鼠的存活率显著高于CIRCI对照组(P =0.046);应激剂量HC治疗组大鼠在伤后第7天和第14天其神经功能评分均显著低于CIRCI对照组(P=0.002,P=0.005)及小剂量MP治疗组(P=0.012,P=0.001),且在伤后第14天其CIRCI患病率显著低于CIRCI对照组(P=0.036).与CIRCI对照组比较,伤后第3天应激剂量HC治疗组的下丘脑室旁核区血脑屏障内皮细胞CD31及紧密连接蛋白Claudin 5的表达水平均显著升高(P=0.013,P=0.000),而伊文思蓝的渗透量显著降低(P =0.020).结论 应激剂量HC可以显著减轻TBI模型大鼠的下丘脑血脑屏障结构和功能的损害,提高机体应激水平,减少CIRCI的发生,促进神经功能恢复,进而增加存活率.%Objective To study the therapeutic effect of early using stress-dose hydrocoritsone on critical illness-related corticosteroid insufficiency (CIRCI) after traumatic brain injury (TBI).Methods The adult male Wistar rats were used to establish a TBI model of hydraulic percussion.The CIRCI rats were screened by the electric stress stimulation at day 1 after injury.The CRICI rats were randomly divided into a CIRCI control group,a low-dose methylprednisolone (MP) treatment group,and a stress-dose hydrocortisone (HC) treatment group.The neurological function scores were measured at day 1,3,7,and 14,respectively after injury in order to compare the degree of neurological dysfunction of the 3 groups,and the survival rate of rats in each group at day 14 after injury was observed.Electric stress stimulation was performed after injury at day 7 and 14 respectively.The CIRCI prevalence of the 3 groups of rats was compared.The hypothalamic tissue pathology of the 3 groups was observed after injury at day 3,7,and 14,respectively.CD31 and Claudin-5 immunofluorescence staining were used to compare the differences of blood-brain barrier endothelial cells in the paraventricular area and the changes of tight junction.Evans blue dye was also used to detect the permeability of blood-brain barrier in that location.Results The survival rate of the rats of the stress-dose HC treatment group was significantly higher than that of the CIRCI control group (P =0.046).The neurological function score in rats of the stress-dose HC treatment group after injury at day 7 and 14 was significantly lower than that of the CIRCI control group (P =0.002,P =0.005) and the lowdose MP treatment group (P =0.012,P =0.001),and its prevalence of CIRCI after injury at day 14 was significantly lower than that of the CIRCI control group (P =0.036).Compared with the CIRCI control group,the expression levels of the paraventricular nucleus blood-brain barrier endothelial cell CD31 and tight junction protein Claudin 5 of the stress-dose HC treatment group after injury at day 3 were increased significantly (P =0.013,P =0.000),and permeation amount of Evans blue decreased significantly (P =0.02).Conclusions The stress-dose HC can significantly reduce the hypothalamic blood-brain barrier structure and functional damage of the TBI model rats,improve the body's stress level,decrease the occurrence of CIRCI,promote the recovery of neurological function,and thereby increase the survival rate.