L-硝基-精氨酸甲酯对严重烫伤早期大鼠血脑屏障通透性和基质金属蛋白酶-9表达的影响  

Effects of L-NAME on blood-brain barrier permeability and MMP-9 expression in rat at the early stage of severe scald

作　　者：王航辉[1] 王璐[1] 惠雪枫[1] 赵琳[1] 刘伯锋[1] 白宏强[1] 杨玲[1] 刘曾旭[2] 

机构地区：[1]延安大学医学院解剖学教研室,延安716000 [2]南昌大学医学院解剖学教研室,南昌330006

出　　处：《解剖学杂志》2009年第2期222-225,共4页Chinese Journal of Anatomy

基　　金：江西省卫生厅课题(20062028)

摘　　要：目的:观察L-硝基-精氨酸甲酯(L-NAME)对严重烫伤早期大鼠血脑屏障(BBB)通透性和基质金属蛋白酶-9(MMP-9)表达的影响,探讨L-NAME对血脑屏障的保护作用。方法:健康SD大鼠,随机分为正常对照组、假烫伤组、烫伤组、烫伤+L-NAME治疗组。烫伤后又设3、6、12、24、48h等5个时相点,用透射电镜观察BBB超微结构变化;紫外分光光度计检测脑伊文氏蓝(EB)含量;免疫组织化学观察脑MMP-9表达。结果:烫伤后脑EB含量明显增高,MMP-9表达升高,差别具有显著性。电镜显示烫伤后大脑皮质的神经细胞线粒体肿胀或溶解。脑毛细血管周围出现空泡化,内皮肿胀,基底膜厚薄不均。L-NAME治疗后,脑EB含量明显下降,MMP-9表达恢复至正常水平,脑毛细血管、神经细胞、突触及基底膜等超微结构基本恢复正常。结论:烫伤后血脑屏障通透性增高与脑内MMP-9表达升高密切相关,提示MMP-9是严重烫伤后血脑屏障损伤的关键因素。早期应用L-NAME能明显减轻烫伤对BBB的损伤,可能与L-NAME抑制MMP-9表达有关。Objective： To observe the effects of L-NAME on blood brain barrier （BBB） permeability and MMP-9 expression in rats at the early stage of severe scald to address whether BBB dysfunction caused by scald is associated with MMP-9 overexpression. Methods： Healthy SD rats were divided into four groups as follows： normal control, sham-scalded group, scald group, scald＋L-NAME group, and the last two groups were quantified at 3,6,12,24, and 48 h post thermal injury. The ultrastructural change of blood brain barrier was observed under transmission electron microscope; Brain evans blue content was examined with an ultraviolet spectrophotometer; Brain water content was detected by caculating dry/wet weight; The change of brain MMP-9 expression after severe scald was determined with immunohistochemical method. Results： Brain evans blue content and the expression of brain MMP-9 were significantly increased after burn. Under the transmission electron microscope, mitochondrion in some neurons of the cerebral cortex were swollen or dissolved. There were vacuolated, swollen endothelium, and abnormity of capillary basement membranes of BBB. Brain evans blue content decreased in serious scalded rats after they were treated with L-NAME. The changes of ultrastrueture of BBB in rat brain with severe scald nearly returned to normal after they were treated with L-NAME, and the expression of MMP-9 was returned to basal level. Conclusion： An increase in MMP-9 expression, associated with increased BBB permeability following thermal injury, indicates that MMP-9 may contribute to observed BBB disruption in peripheral thermal injury. An increase in BBB permeability after severe scald, which can be significantly restricted by L-NAME at the early stage, may be linked to restraining MMP-9 expression in rat after severe scald.

关 键 词：烫伤 血脑屏障 L-硝基-精氨酸甲酯 基质金属蛋白酶-9 

分 类 号：R644[医药卫生—外科学]