热射病小鼠早期中枢神经炎症和外周炎症的变化

Inflammatory responses of central and peripheral nerve system in early recovery stage of heat stroked mice

目的探讨热射病小鼠早期(0~24 h)中枢神经炎症和外周炎症的变化及其相关性。方法 70只BALB/c雄性小鼠按随机数字表法分为正常对照组和热射病后各时相(0、1、6、12、24 h)观察组。应用环境模拟舱建立热射病小鼠模型。观察记录各组小鼠生存率、直肠温度变化和体质量变化,Real-time PCR检测大脑皮层和海马炎症因子TNF-α、IL-1β和IL-6的表达,ELISA测定外周血清中炎症因子TNF-α、IL-1β和IL-6的分泌情况,鲎试剂动态浊度法检测血清中内毒素浓度。结果热暴露后小鼠直肠温度超过42℃,1~2 h出现低温期,24 h后小鼠存活率为78.57%,成功制备热射病小鼠模型;大脑皮层及海马在热暴露后1 h炎症因子TNF-α、IL-1β、IL-6的基因表达显著增加并达到最高峰值(P<0.01),6 h后逐渐降低但仍明显高于正常对照组(P<0.01),24 h后基本恢复至正常对照组水平(P>0.05);外周血清中炎症因子TNF-α、IL-1β和IL-6在1 h后含量显著增加(P<0.01),之后缓慢下降,到24 h后仍高于正常对照组(P<0.01);血清内毒素在热暴露即刻(0 h)开始明显升高,6 h后达到峰值,至24 h仍明显高于正常对照组(P<0.01)。结论热射病小鼠在热暴露12 h内中枢神经系统出现一过性炎症反应,而外周炎症反应持续至24 h之后,提示热射病小鼠早期中枢神经炎症反应与外周炎症反应可能是相互独立发生。

Objective To investigate the change and correlation of inflammatory response between the central and peripheral nerve system in early recovery stage（ 0 ～ 24 h） of mice after heat stroke（ HS）.Methods A total of 70 BALB / c male mice were randomly divided into control（ CON） group and other 5different phase-group after HS（ HS-0 h,HS-1 h,HS-6 h,HS-12 h,and HS-24 h）. HS mouse model was established using environmental stimulation chamber. The survival,rectal temperature,and body weight loss were measured. The change of tumor necrosis factor alpha（ TNF-α）,interleukin（ IL）-1β,and IL-6 in the cortex and hippocampus was determined by quantitative real-time polymerase chain reaction（ PCR）. The serum levels of TNF-α,IL-1β,and IL-6 was measured by enzyme-linked immunosorbent assay（ ELISA）.The endotoxin concentration in the serum was detected by Kinetic Turbidimetric Tachypleus Amebocyte Lysate. Results The rectal temperature in mice exceeded 42 ℃ after heat exposure. Hypothermia occurred in 1 ～ 2 h and the survival rate of mice was 78. 57% after 24 h. These suggested that HS mouse model was successfully generated. Compared to the control group,the m RNA expression of TNF-α,IL-1β,and IL-6 in the cerebral cortex and hippocampus of HS groups was increased rapidly,reaching the maximum at 1 h（ P〈0. 01）. The expression was then gradually decreased after 6 h and approached to the normal level at 24 h（ P〈0. 05）. At 6 h,the expression of these inflammatory factors was still higher than the CON group（ P〈0. 01）. The expression levels of TNF-α,IL-1β,and IL-6 in the peripheral serum were increased significantly at 1 h,then decreased. At 24 h,the levels still remained higher than the CON group（ P〈0. 01）. The concentration of endotoxin in the serum was elevated at 0 h,reached the peak at 6 h and maintained the high secretion level until 24 h（ P〈0. 01）. Conclusion The secretion of inflammatory factors in central nerve system response to heat exposure is transient within 12 h,while is persistent to 24 h in peripheral inflammatory secretion. The different inflammation response between the central and peripheral nerve system after heat stroke implies that they are independent of each other in early stage of recovery in mice.