不同降温方式对脑外伤后伤灶区c-fos mRNA和神经生长因子表达的影响

Effects of Hypothermia on c-fos mRNA and NGF Expression in the Rat Brain Following Traumatic Brain Injury

目的通过对大鼠重型脑挫裂伤后体温的干预,观察不同降温方式对脑外伤后伤灶区c-fos mRNA和神经生长因子(nerve growth factor,NGF)表达的影响,了解其表达强度是否与伤后不同降温方式对脑损伤的保护机制有关。方法健康成年SD大鼠336只,随机分为四组(每组84只),除假手术组外各组动物均按自由落体法造成重度脑挫裂伤;每组又按处死时间分为七个亚组(每亚组12只),分别检测c-fos mRNA(6只)与NGF(6只)的表达。结果①伤后4 h、8 h、12 h与24 h,全身亚低温组与局部亚低温组c-fos mRNA表达明显高于TBI组(P<0.01),其他各时点无差异;TBI组在伤后4 h、8 h、12 h、24 h与3 d,c-fos mRNA表达均明显高于假手术组(P<0.01)。②伤后4 h、8 h,全身亚低温组与局部亚低温组NGF表达与TBI组无明显差异(P>0.05);而在伤后12 h、24 h、3 d、5 d与7 d,两亚低温组NGF表达明显高于TBI组((P<0.05或P<0.01)。③全身亚低温组与局部亚低温组在伤后各时间点c-fos mRNA和NGF表达无显著性差异(P>0.05)。结论脑外伤后亚低温可促进c-fos mRNA和NGF表达上调,全身亚低温与局部亚低温两种不同降温方式无明显差异。

Objective To observe the effects of hypothermia on cerebral c-fos mRNA and nerve growth factor （NGF） expression following traumatic brain injury. Methods 336 aduh SD rats were randomly separated to four groups. Three groups were subjected to traumatic brain injury by the Feeney＇s method except for sham operation group. Every group was then separated to 7 subgroups according to different decapitated time. C-fos mRNA and NGF expression was then determined respectively. Results C-fos mRNA expression in systemic hypothermia group and focal hypothermia group was significantly higher than TBI group at 4 h, 8 h, 12 h and 24 h after traumatic brain injury （ P 〈 0. 01 ）. NGF expression in systemic hypothermia group and focal hypothermia group was significantly higher（ P 〈 0.05 or P 〈 0.01 ） than TBI group at different time points after traumatic brain injury except for 4 h and 8 h which had no significant difference. C-fos mRNA and NGF expression in systemic hypothermia group and focal hypothermia group had no significant difference （P 〉 0.05 ）. Conclusion Both systemic hypothermia and focal hypothermia could up-regulate the expression of c-fos mRNA and NGF for the traumatic brain injury.