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目的探讨Toll样受体4(TLR4)表达与新生大鼠脑组织缺氧缺血损伤的关系。方法85只7日龄新生大鼠按随机数字表法分为对照组41只和缺氧缺血组(实验组)44只,实验组死亡4只,对照组死亡1只。实验组制备新生大鼠缺氧缺血性脑损伤模型,两组分别于实验组缺氧缺血术后6、12、24、72 h及7天取大鼠脑组织制备石蜡标本(n=8),用苏木精-伊红染色观察脑组织病理变化,采用免疫组化方法分析大脑皮质和海马部位TLR4蛋白表达。结果 TLR4在大脑皮质和海马部位的神经元、小胶质细胞均有表达。实验组大脑皮质和海马TLR4表达于缺氧缺血后6 h即增加(0.327±0.033,0.304±0.038),12 h达峰值(0.436±0.043,0.419±0.041),24 h(0.434±0.043,0.419±0.041)和12 h比较无明显变化,72 h(0.301±0.021,0.282±0.023)和7天(0.274±0.029,0.258±0.028)表达下降。对照组TLR4表达水平较低,各时间点表达无明显变化。实验组各时间点大脑皮质和海马TLR4表达均高于对照组,差异有统计学意义(P<0.05)。结论 TLR4可能参与了新生大鼠脑组织缺氧缺血损伤的过程。
Objective To investigate the relationship between Toll-like receptor 4 (TLR4) expression and hypoxic-ischemic brain damage in neonatal rats. Methods Totally 85 neonatal 7-day-old rats were divided into control group (n = 41) and hypoxic-ischemic group (n = 44) by random number table method. There were 4 deaths in the experimental group and 1 death in the control group. In the experimental group, the model of hypoxic-ischemic brain damage was established in neonatal rats. Two groups of rats were sacrificed at 6, 12, 24, 72, and 7 days after hypoxia-ischemia respectively to prepare paraffin-embedded specimens (n = 8 ). The pathological changes of brain tissue were observed by hematoxylin-eosin staining. The expression of TLR4 protein in cerebral cortex and hippocampus was analyzed by immunohistochemistry. Results TLR4 was expressed in neurons and microglia in cerebral cortex and hippocampus. The expression of TLR4 in cerebral cortex and hippocampus in experimental group increased at 6 h after hypoxia-ischemia (0.327 ± 0.033, 0.304 ± 0.038), peaked at 12 h (0.436 ± 0.043, 0.419 ± 0.041) and 24 h (0.434 ± 0.043, 0.419 ± 0.041) and no significant change at 12 h, but decreased at 72 h (0.301 ± 0.021,0.282 ± 0.023) and 7 days (0.274 ± 0.029,0.258 ± 0.028). The expression level of TLR4 in the control group was low, and there was no significant change at each time point. The expression of TLR4 in cerebral cortex and hippocampus in experimental group at each time point was higher than that in control group, with statistical significance (P <0.05). Conclusion TLR4 may be involved in the process of hypoxic-ischemic brain damage in neonatal rats.