Abstract:

Objective   To study the effects of chronic arsenic poisoning on the  change of the dentate gyrus ultrastructure and  learning and memory in mice. Methods   80 healthy adult Kunming mice, weighting 20-22g, were divided into four groups: the normal control group, the low dose group, the middle dose group and the high dose group (10 males and 10 females in each group), which were fed with distilled water, 1/5 LD50, 1/10 LD50 and 1/40 LD50 AS2O3 for 3 months  respectively, and  the dose was adjusted according to their weight changes. Then the ability of learning and memory was tested by a Y-maze, and the ultra-structure of the dentate gyrus was observed by transmission electron microscopy. Results    The ability of learning and memory of the high dose group was significantly lower than that of the normal control group(P＜0.05), and some neurons of the dentate gyrus of each poisoned group showed a shrunken cellular membrane, diminished cell body and increased electron density of nuclear chromatin under transmission electron microscopy. Conclusion    Chronic arsenic poisoning might damage the ability of learning and memory in mice, which may be related with  damaged neurons of the dentate gyrus.

Key words: Arsenic poisoning; Maze learning; Memory; Dentate gyrus; Mice