早年慢性应激对青春期大鼠攻击行为及下丘脑腹内侧核和前额皮质脑源性神经营养因子表达的影响

Effect of early chronic life stress on aggressive behavior and expression of brainderived neurotrophic factor in hypothalamus and prefrontal cortex in puberty rats

目的探讨早年慢性应激对青春期大鼠攻击行为以及大脑下丘脑腹内侧核和前额皮质脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)表达的影响。方法将20只SD大鼠分为实验组和对照组。实验组大鼠出生后21 d开始进行社会孤养、日夜颠倒、社会刺激性实验和居住-入侵实验等多种早年应激3周。免疫组化检测下丘脑腹内侧核和前额皮质BDNF的表达。结果实验组在居住-入侵实验和中性环境实验中攻击/威胁比[分别为(12.45±9.27)、(10.84±4.93)]和攻击持续时间[分别为(333.10±76.34)、(322.20±57.67)s]均显著高于对照组(P<0.01),而攻击潜伏期[分别为(15.20±11.07)、(18.30±11.32)s]显著低于对照组(P<0.01),并且表现出暴力攻击行为。免疫组化检测结果显示,实验组下丘脑腹内侧核BDNF表达(0.20±0.09)高于对照组(P<0.05),前额皮质BDNF(0.19±0.08)表达水平低于对照组(P<0.05)。结论早年慢性应激引起青春期大鼠暴力攻击行为以及下丘脑腹内侧核和前额皮质BDNF表达改变,提示青春期暴力攻击行为可能与早年慢性应激所致BDNF表达改变有关。

Objective To explore the effect of early chronic life stress on aggressive behavior and expression of brain-derived neurotrophic factor （BDNF） of ventromedial hypothalamus nucleus and prefrontal cortex in puberty rats. Methods Twenty rats were randomly divided into 2 groups： an experimental group and a control group. The rats of the experimental group were given a series of stress including social isolation, reversal of day and night, social stimulation and resident-intruder confrontation at the 21st day after birth for 3 weeks. The expression of BDNF in ventromedial hypothalamus nucleus and prefrontal cortex was determined by immunohistochemistry. Results The attack/threat （A/T） ratio （ 12.45 ±9.27, 10.84 ±4.93） and duration of attack manifestations （DAM） （333.10 ± 76.34, 322.20 ± 57.67 ） in resident-intruder test and neutral arena test increased significantly in the experimental group as compared with the control group （ P 〈 0.01 ）, while the latency of the first attack （ 15.20 ± 11.07, 18.30 ± 11.32 s） decreased significantly （ P 〈 0.01 ）. Moreover, the rats of experimental group exhibited violence behavior. Compared with the control group, the expression of BDNF elevated significantly in ventromedial hypothalamus nucleus （0.20±0.09, P 〈 0.05 ）, and decreased significantly in prefrontal cortex （0.19 ± 0.08, P 〈 0.05 ） in the experimental group. Conclusion The violence behavior in puberty rats induced by early chronic life stress may be associated with the altered expression of BDNF in ventromedial hypothalamus nucleus and prefrontal cortex.