颈交感神经阻滞对放烧复合伤小鼠HPA轴的调节及相关机制研究

Effect of cervical sympathetic ganglia block on HPA axis in mice with combined radiation and burn injury and its related mechanisms

目的探讨颈交感神经阻滞(SB)对放烧复合伤小鼠HPA轴的调节及可能机制。方法TBSA15%Ⅲ度烧伤合并5Gy放射损伤小鼠分为:对照组、放烧复合伤组及伤后SB治疗组,比较各组血清糖皮质激素(GC)及ACTH浓度的差异;同时利用膜片钳技术检测各组间海马NMDA受体通道特性的变化。另外,将腹腔注射足量NMDA受体阻断剂MK-801的小鼠分为:放烧复合伤组、伤后SB治疗组,比较两组血清GC及ACTH浓度的差异。结果放烧复合伤后血GC及ACTH水平显著升高,SB治疗组血GC和ACTH水平显著底于放烧复合伤组。SB组海马NMDA受体通道开放概率、开放时间常数τ1、τ2虽然高于对照组,但显著低于放烧复合伤组。足量MK-801预处理的放烧复合伤组与SB组之间的血清GC和ACTH水平无显著差异。结论SB通过降低NMDA受体的活性,抑制了严重创伤(放烧复合伤)小鼠HPA轴的亢进。

Objective To explore the roles of cervical sympathetic ganglia block （SB） in HPA axis of mice with combined radiation and burn injury and their related mechanisms. Methods Kunming mice were divided into control group, injury group （inflicted with 5 Gy irradiation and 15% TBSA full thickness burn injury） , SB group （ inflicted with combined injury, then treated daily by cervical SB）. Serum GC, ACTH concentration and hippocampal NMDA receptor activity in each group were analyzed. In addition, another 20 Kunming mice （ all injected intraperitoneally with enough MK-801 ） were divided into control （ inflicted with combined radiation and burn injury） and SB group （ inflicted with combined injury, then treated daily by cervical SB）. Serum GC and ACTH concentration of these group were also detected. Results As compared with control group, serum GC, ACTH concentration and hippocampal NMDA receptor activity in injury group increased significantly. GC, ACTH concentration and NMDA receptor activity were higher than that of control group, but lower than that of injury group markedly. There were no significant differences of serum GC and ACTH concentration between injury group pretreated with MK-801 and SB group pretreated with MK-801. Conclusion By inhibiting NMDA receptor activity, SB promotes homeostatic restoration of HPA axis in mice of combined radiation and burn injury.