化学染毒及高温环境对孕鼠子代海马神经元形态及神经行为的影响

Effects of chemical compounds exposure and hyperthermal environment to pregnant rats on hippocampus neuronal morphology and neurobehavioral development of offsprings

目的探讨化学毒物及高温环境对孕鼠子代海马神经元的形态和神经行为的影响。方法将孕鼠随机分为对照组、染毒组、染毒联合高温组(联合组)和高温组,分别在孕早期(D1-D10)给予相应的处理。在生后不同时间观察新生大鼠大脑的发育以及海马神经元的形态变化,并检测新生大鼠的早期反射活动。结果各组新生大鼠脑组织无畸形,但染毒组和联合组海马CA1区变性坏死的神经元数量明显多于对照组和高温组(P<0.01)。出生1个月后染毒组和联合组海马CA1区神经元的数量明显少于对照组和高温组(P<0.05)。行为学检测发现染毒组、联合组、高温组早期反射出现的时间均明显长于对照组。结论化学染毒可导致新生大鼠海马神经元的变性、坏死。染毒联合高温并不加重脑组织海马神经元的损害,但高温对动物的早期正常反射的出现却有明显的延迟作用。

Objective To observe the effects of chemical compounds exposure and hyperthermal environment to pregnant rats on the hippocampus neuronal morphology and neurobehavioral development of their offsprings. Methods Pregnant rats were divided into 4 groups randomly： the control group; chemical compounds exposure group, chemical compounds combined hyperthermal exposure group and hyperthermal group. The control group was living in normal condition; the chemical compounds exposure group in a cabin with benzene （20. 26 ＋_ 0.80） mg/m3, toluene （39.66 _＋ 4.23 ） mg/m3, dimethylbenzene （42.40 ± 2.85 ） mg/m3, and formaldehyde （23. 13 ± 1.30） mg/m3 ; the hyperthermal group was kept in an atmosphere of 38.5℃; and the combined group was exposed to the chemical compounds and high temperature at the same time. All animals were treated respectively 2 h per day for 10 d since their pregnancy. Their offspring were lived in normal condition. The development of brain and changes of hippocampus neuronal morphology were observed just or 1 month after born. The primary reflex activity of new-born rats was also examined. Results There was no abnormality in the brain of new born rats from 4 groups. In the chemical compounds exposure and the combined exposure groups, the number of degeneration and necrosis neurons in CA1 region of hippoeampus were significantly more than those in control and hyperthermal groups （P 〈 0.01 ）. A month after born, the number of CA1 neurons were lesser than those in control and hyperthermal groups （P 〈 0.01 ）. The time of ear- ly period reflex appearance in chemical compounds exposed group, chemical compounds combined hyperthermal exposed group and hyperthermal group were significantly longer than that in control group. Conclusion Chem- ical compounds exposure can induce the degeneration and necrosis of hippocampus neurons. Chemical com- pounds combined hyperthermal exposure does not aggravate the damage to hippocampus neurons, however hy- perthermal environment prolongs the time of early normal period reflex appearance.