A NEW NEUROTOXICOLOGICAL TEST SYSTEM USING NERVE CELL LINE

本世纪，工业界生产出了许多新的化学品。我们建立了体外神经毒理学试验系统，以评估这些化学物质的神经毒性潜能。(1)本研究采用BALB/c小鼠背根神经节神经元与小鼠神经母细胞瘤细胞（N18TG-D2）杂交细胞系N18DRG-D2诱导微核和凋亡。碘化丙啶对微核的诱导作用在顺铂治疗96小时达到峰值，且顺铂诱导的微核频率呈剂量依赖性增加。然而，在顺铂治疗后，凋亡的微核数量（碘化proidium双染色和TUNEL法）没有增加。(2)膜动作电位的改变用3,3 '-二苯二氯碳氰碘化染色后用荧光光度计测定膜动作电位。N18DRG-D2暴露于顺铂后荧光强度减弱。(3)细胞内钙离子浓度的变化fura-2染色后用荧光光度计测定膜动作电位。N18DRG-D2暴露于顺铂后荧光强度减弱。这些结果表明，利用N18DRG-2细胞系建立新的神经毒理学测试系统可能有助于估计神经毒性物质。

Many new chemicals have produced in this century from industrial circles. We established a in vitro neurotoxicological test system for the purpose of assessing the neurotoxic potential of these chemicals.(1) Induction of micronuclei and apoptosisHybrid cell line N18DRG-D2 of BALB/c mouse dorsal root ganglion neuron and mouse neuroblastoma cell (N18TG-D2) was used in this study. Induction of micronuclei by propidium iodide peaked at 96 hours of cisplatin treatment and frequency of micronuclei induced by cisplatin increased dose dependent manner. However, number of apoptotic micronuclei (double staining with proidium iodide and TUNEL method) did not increase following cisplatin treatment.(2) Alteration of membrane action potentialMembrane action potential was determined using a fluorophotometer after stained with 3, 3'-dipenty loxacarbocyanine iodide. Fluorescence intensity of N18DRG-D2 was attenuated after exposure to cisplatin.(3) Alteration of intracellular calcium ion concentrationMembrane action potential was determined using a fluorophotometer after stained with fura-2. Fluorescence intensity of N18DRG-D2 was attenuated after exposure to cisplatin.These results suggested that a new neurotoxicological test system using N18DRG-2 cell line might be useful for estimating neurotoxic substances.