槲皮素对缺氧缺血性脑损伤新生大鼠神经再生的影响

Effects of Quercetin on nerve regeneration in neonatal rats with hypoxic-ischemic brain damage

目的探讨槲皮素对缺氧缺血性脑损伤(HIBD)的神经保护机制。方法 48只7日龄新生SD大鼠随机分为假手术组、HIBD组、Que组,每组16只。HIBD组和Que组经右颈总动脉结扎并缺氧制作HIBD模型,假手术组仅分离右颈总动脉。Que组在造模后即刻予腹腔注射槲皮素(40 mg/kg),每日1次,连续7 d;假手术组和HIBD组在同一时间点予等量生理盐水腹腔注射。各组大鼠在末次给药1 h后行神经功能评分,28日龄行Morris水迷宫检测空间学习记忆能力。水迷宫实验结束后断头取脑,HE染色观察海马病理学改变,免疫组织化学法检测海马CA1区脑源性神经营养因子(BDNF)和神经生长相关蛋白(GAP-43)表达情况。结果三组大鼠的神经功能缺陷评分和学习记忆能力差异均有统计学意义(P<0.01),HIBD组神经功能缺陷评分最高,学习记忆能力最差。病理检查显示,假手术组大鼠海马神经元结构完整;HIBD组海马结构疏松紊乱,且出现神经元丢失;Que组与HIBD组比较,结构疏松紊乱较轻,神经元数量有所增多。三组大鼠海马CA1区BDNF和GAP-43阳性表达差异均有统计学意义(P<0.01),HIBD组均低于Que组和假手术组,Que组低于假手术组,差异有统计学意义(P<0.01)。结论槲皮素可以通过上调海马CA1区BDNF和GAP-43表达,促进神经再生,改善HIBD新生大鼠的远期学习记忆能力,发挥脑保护作用。

Objective To explore the protective effects of Quercetin on hypoxic ischemic brain damage （HIBD）. Methods Forty-eight 7-day-old SD rats were randomly divided into sham-operation group, HIBD group and Que treatment group, 16 rats each. HIBD group and Que treatment group were treated by ligation of right common carotid artery to make anoxia and build HIBD model; sham-operation group had the separation of the right common carotid artery only. Que treatment group were injected intraperitoneally with quercetin （40 mg/kg） once a day for 7 days immediately after modeling while sham-operation group and HIBD group received equivalent normal saline at the same time. The rats in each group were scored of neurological function at 1 h after the last administration, and the ability of spatial learning-memory was tested by Morris water maze at the age of 28 days. After performing the test above, all rats were decapitated and the brains were taken. Pathological changes of hippocampus were observed by HE staining; the expression of brain-derived neurotrophic factor （BDNF） and nerve growth associated protein （GAP-43） in hippocampus CA1 area were detected by immunohistochemistry. Results There were significant differences in neurological deficit score and learning-memory ability among the three groups （P〈0.01）, and neurological deficit score was the highest and the learning-memory ability was the lowest in HIBD group. Pathological examination showed that the structure of hippocampal neurons was intact in sham-operation group. It was loose and disorder, and even loss of neurons in HIBD group. Compared with the HIBD group, the loose in the structure of hippocampal was lighter, and the number of neurons was increased in the Que treatment group. There was statistical difference in the positive expression of BDNF and GAP-43 in the hippocampal CA1 area among the three groups （P〈0.01）, with those in HIBD group being lower than in Que treatment group and sham-operation group and those in treatment group being lower than in sham-operation group （P〈0.01）. Conclusions Quercetin can enhance the expression of BDNF and GAP-43 in hippocampal CA1 region, promote nerve regeneration, improve the longterm learning-memory ability of HIBD neonatal rats, and protect the brain.