新生大鼠缺氧缺血性脑损伤NF—κBp65和TLR4表达变化探讨

Expression of NF-κBp65 and TLR4 in neonatal rats with hypoxic-ischemic brain damage

目的探讨核转录因子KBp65（nuclear factor—kappa Bp65，NF-κBp65）和Toll样受体4（Toll—like receptor4，TLR4）在新生大鼠脑组织中的表达及其变化规律及相关性，研究两者在新生儿缺氧缺血性脑损伤发病机制中的作用。方法出生7d新生大鼠随机数字表法分对照组和缺氧缺血组，制备新生儿缺氧缺血性脑损伤模型，并于缺氧缺血术后6h、12h、24h、72h及7d取其脑组织制备光镜石蜡标本，观察脑组织的病理变化。采用免疫组织化学方法分析NF—κBp65和TLR4的表达。结果新生大鼠缺氧缺血性脑损伤过程中，NF—κBp65和TLR4在神经元、小胶质细胞均有表达，以大脑皮质和海马部位表达变化明显；于缺氧缺血后6hNF—κB065（0．2193±0.0247，Q2157±0.0304）和TLR4（0.3271±0.0333，0.3039±0.0379）表达增加，24hNF—κBp65（0．3564±0．0235，0．3365±0．0232）和TLR4（0．4342±0．0428，0．4193±0．0413）表达达到峰值，72hNF—κBp65（0．2892±0．0320，0．2609±0．0212）和TLR4（0．3005±0．0209。0．2820±0．0226）和7dNF—κBp65（0．2479±0．0340，0．2421±0.0254）和TLR4（0．2744±0.0288，0.2571±0.0275）表达下降。结论NF—κBp65与TLR4表达呈正相关，提示可能在新生大鼠缺氧缺血性脑损伤中有相同机制。

Objective To investigate the expression of nuclear factor-kappa Bp65 （NF-κBp65）and Toll-like receptor 4 （TLR4）protein in the brain tissues of 7-day-old Sprague-Dawley（SD） rats with cerebral hy-poxia-ischemia encephalopathy（HIE） and to explore the role of TLR4 and NF-κBp65 in the pathogenesis of neo- natal rats with hypoxic-ischemic brain damage. Methods Seven-day SD rats were randomly divided into the experimental group and the control group. Brain pathological changes were observed in light microscopy at 6 h, 12 h,24 h ,72 h ,7 d after HIE. The expression of TLR4 and NF-κBp65 in brain tissues were analyzed by immunohistochemistry method. Results NF-κBp65 and TLR4 were expressed in the neuron and microglia of control group and experimental group. The expression were most significant at cerebral cortex and hippocamp. However, the expression of NF-κBp65and TLR4 began to increase at HIE 6h： NF-κBp65 （0. 219 3 ± 0. 024 7,0. 215 7 ± 0. 0304）and TLR4（0. 327 1 ：tO. 033 3,0. 303 9 ＋0. 037 9） ,and achieved the hightest at HIE 24h：NF-KBp65 （ 0. 356 4 ± 0. 023 5,0. 336 5 ± 0. 023 2 ） and TLR4 （ 0. 434 2 ± 0. 042 8,0. 419 3 ± 0. 04 1 3 ）, then decreased at HIE 72 h： NF-κBp65 （ 0. 289 2 ± 0. 032 0,0. 260 9 ± 0. 021 2 ） and TLR4 （ 0. 300 5 ± 0. 020 9,0. 282 0 ± 0. 022 6 ）, and HIE 7 d： NF-KBp65 （0. 247 9 ± 0. 034 0,0. 242 1 ± 0. 025 4） and TLR4 （0. 274 4 ± 0. 028 8,0. 257 1 ± 0. 027 5 ）. Conclusion There is a positive correlation between NF-κBp65 and TLR4 in rats with HIE. It suggested that they may have the same pathophysiology development in HIE.