甲状腺素对重型颅脑损伤大鼠神经细胞凋亡、NSE及IL-6的影响

目的 通过观察甲状腺素对重型颅脑损伤大鼠神经细胞凋亡、血清神经元特异性烯醇化酶(NSE)、白细胞介素(IL)-6的影响及血清FT3、FT4的改变,探讨甲状腺素对重型颅脑损伤脑组织的保护作用.方法 90只SD大鼠分为对照组、模型组、左甲状腺素钠片低剂量组、左甲状腺素钠片中剂量组、左甲状腺素钠片高剂量组5组,每组各18只,参照Feeney's自由落体打击造模法复制动物模型;于伤后6h灌胃.灌胃后24、72、168 h分别通过TUNEL法、ELISA法及放射免疫法检测神经细胞凋亡、血清NSE、IL-6及血清FT3、FT4水平.结果 (1)重型颅脑损伤大鼠受伤后血清FT3、FT4水平低于正常水平,FT4在168h降到最低,甲状腺素可使FT3、FT4水平升高.(2)重型颅脑损伤大鼠受伤后出现明显的神经细胞凋亡,这种凋亡持续至168 h.中剂量及高剂量甲状腺素在24 h即可以改善神经细胞凋亡,低剂量甲状腺素在168 h才可以改善神经细胞凋亡.(3)重型颅脑损伤大鼠血清NSE、IL-6于伤后明显升高,一直持续到168 h.中剂量及高剂量甲状腺素在72 h即可以降低血清NSE、IL-6水平.结论 外源性甲状腺素对重型颅脑损伤大鼠脑组织具有保护作用.

Effect of thyroxin on neuronal apoptosis,serum NSE and IL-6 in rats with severe traumatic brain injury

Objective To explore the protective effect of thyroxin on severe traumatic brain injury of brain tissue by observing the effect of thyroxin on neuronal apoptosis,serum neuronal specific enolase(NSE),interleukin-6 (IL-6) and serum FT3 and FT4.Methods A total of 90 SD rats was randomly divided into control group,model group,low dosage of levothyroxine sodium tablets group,moderate dosage of levothyroxine sodium tablets group and high dosage of levothyroxine sodium tablets group,18 rats in each group.The animal model was reproduced by referring to Feeney's free fall impact modeling.Intragastric administration was performed at 6 h after injury.The levels of neuronal apoptosis and serum NSE,IL-6,FT3 and FT4 were detected by TUNEL method,ELISA method and radioimmunoassay at 24,72,168 h after intragastric administration.Results (1) After severe traumatic brain injury,the levels of serum FT3 and FT4 were under the normal and the level of FT4 was decreased to the lowest at 168 h.Thyroxine could increase the levels of FT3 and FT4.(2) Significant neuronal apoptosis was observed in rats with severe craniocerebral injury,and the apoptosis continued until 168 h.Moderate and high dose of thyroxine could improve neuronal apoptosis within 24 h,while low dose of thyroxine changed within 168 h.(3) The levels of serum NSE and IL-6 were increased significantly in rats after severe traumatic brain injury until 168 h,and they could be decreased by moderate and high dose of thyroxine within 72 h.Conclusion Exogenous thyroxine can protect brain tissue in rats with severe traumatic brain injury.