Hass U, Lund S P, Simonsen L
Department of Toxicology and Biology, National Institute of Occupational Health, Copenhagen, Denmark.
Neurotoxicology. 1997;18(2):547-51.
The persistence of neurobehavioral effects in female rats (Mol:WIST) exposed to 500 ppm technical xylene (dimethylbenzene, CAS-no 1330-20-7) for 6 hours per day on days 7-20 of prenatal development was studied. The dose level was selected so as not to induce maternal toxicity or decreased viability of offspring. Investigations of learning and memory abilities were performed using a Morris water maze. This task requires rats to spatially navigate, using distal extramaze cues to locate a small platform under the surface of the water in a large pool. At the age of 16 weeks, the exposed offspring showed impairments when the platform was relocated in the pool. Impaired performances after platform relocation were also observed in exposed offspring at 28 and 55 weeks of age, although the difference was not statistically significant at 55 weeks. These data could indicate that the effect was partly reversible, although over a long time period. However, another explanation could be that the animals became more practised at solving the problem (finding the platform) as continued testing occurred and therefore were able to compensate for the neurotoxic effect of the prenatal xylene exposure. Further studies are planned to investigate whether neurobehavioral effects resulting from prenatal xylene exposure can interact with neurophysiological aging processes.
研究了在产前发育第7至20天每天暴露于500 ppm工业二甲苯（二甲基苯，CAS编号1330-20-7）6小时的雌性大鼠（Mol:WIST）神经行为效应的持续性。选择该剂量水平是为了不诱发母体毒性或降低后代的生存能力。使用莫里斯水迷宫对学习和记忆能力进行了研究。这项任务要求大鼠进行空间导航，利用池外远处的线索在大水池的水面下找到一个小平台。在16周龄时，当平台在水池中重新放置时，暴露组后代表现出损伤。在28周龄和55周龄的暴露组后代中也观察到平台重新放置后表现受损，尽管在55周时差异无统计学意义。这些数据可能表明这种影响部分是可逆的，尽管需要很长时间。然而，另一种解释可能是随着持续测试的进行，动物在解决问题（找到平台）方面变得更加熟练，因此能够补偿产前二甲苯暴露的神经毒性作用。计划进一步研究产前二甲苯暴露引起的神经行为效应是否会与神经生理衰老过程相互作用。
