Experimental study on the effects of organic solvent exposure to development of GABAergic system in juvenile rats

1.研制了一种适用于幼年动物（大鼠）接触有机溶剂蒸气的暴露系统及其吸入研究。暴露室内环境为幼龄大鼠设计。一个普通的老鼠笼，有气体的入口和出口，完全包裹在一个特殊的气密塑料袋，然后作为暴露室。利用该系统对3周龄大鼠进行了吸入实验。暴露方案为：间二甲苯250 ppm，每天6小时，连续14天。行为学研究采用rotarod法观察间二甲苯对中枢神经系统发育的影响。一般来说，运动系统的协调性是用这个测试来评估的。暴露的大鼠表现出比对照组更好的协调性，需要进一步的研究来解释这些意想不到的结果。组织学研究：连续照射后进行脑切片。采用Luxol快速蓝和甲酚紫双染色，观察可能累及髓磷脂的病变。未观察到明显变化。使用抗谷氨酸脱羧酶抗体和抗gaba_a受体α 6亚基抗体进行免疫组化研究，但未发现明显变化。使用[^3H]Ro15-4513进行受体结合放射自显影。结合分布与GABA_A受体α 6亚基免疫染色信号分布一致。未观察到明显变化。目前的结果表明，这种暴露方案可能会对运动功能产生一些显著的变化。在今后的研究中，儿茶酚胺能和/或血清素能系统的研究应与氨基丁酸能系统的研究一并纳入。

1.Development of an exposure system suitable for exposing vapor of organic solvents to juvenile animals (rats) and inhalation study using the systemAn exposure system suitable for exposing vapor of organic solvents to juvenile animals was developed.The inner environment of the exposure chamber was designed for young rats. An ordinary mice cage with gas inlets and outlets was completely wrapped with a special gas-tight plastic bag, which was then used as the exposure chamber. With this system, inhalation study in three-week old rats was conducted. The protocol of the exposure was as follows : m-xylene at 250 ppm, 6 h/day for 14 consecutive days.2.Behavioral studyRotarod test was employed to see the effect of m-xylene of the development of the CNS. Generally co-ordination of the motor system is assessed with this test. Exposed rats showed better coordination than controls, and further study is warranted to explain the unexpected results.3.Histological studyBrain sections were made after the series of exposures. The section was stained using Luxol Fast Blue and Cresyl Violet double stain, to see possible lesions involving myelin. No significant change was observed. Immunohistochemical studies using anti-glutamate decarboxylase antibody and anti-GABA_A receptor alpha 6 subunit antibody were done, but no significant change was pointed out.Receptor binding autoradiography using [^3H]Ro15-4513 was performed. The distribution of the binding was identical to that of signals in immunostain of GABA_A receptor alpha 6 subunit. No significant change was observed.The present results suggested that there may be some significant change in locomotor function with this exposure protocol. A study in catecholaminergic and/or serotonergic system should be included along with that in GABAergic systems in the future studies.