Effects of long-term low-level arsenic exposure through drinking water on cognitive learning in mice

Objective To observe the effects of long-term low dose arsenic exposure through drinking water on learning ability of different generations of C3H and Balb/c mice. Methods Mice (C3H and Balb/c) were exposed to arsenic at 0 mg/L (control) and 85 mg/L (20 female mice and 10 male mice per group). The control group and F1, F2, F3 and F4 mice were selected and divided into 5 experimental groups, 8 mice in each group. Their offsprings were detected by the Morris water maze test (the average escape latency of 1 to 5 days) and spatial probe test (the times of through target area on the sixth day). Statistical analysis was performed with SPSS 18.0 software. Results The average escape latencies of 1 to 5 days in C3H control group were (48.09 ± 2.63), (46.09 ± 3.27), (42.72 ± 3.29), (39.31 ± 2.69) and (36.75 ± 3.92) s, F1 were (49.59 ± 3.29), (47.34 ± 3.01), (44.28 ± 6.58), (44.50 ± 1.67) and (42.16 ± 2.27) s, F2 were (51.41 ± 0.78), (48.88 ± 1.45), (45.54 ± 1.46), (43.94 ± 1.69) and (42.22 ± 3.27) s, F3 were (50.91 ± 4.20), (49.78 ± 5.18), (48.03 ± 3.45), (46.16 ± 4.42) and (44.06 ± 1.04) s, F4 were (52.66 ± 4.60), (52.38 ± 5.78), (49.06 ± 1.22), (47.69 ± 2.34) and (46.47 ± 1.56) s. The average escape latencies of Balb/c control group were (50.91 ± 2.84), (47.03 ± 4.22), (45.56 ± 4.53), (39.72 ± 5.90) and (36.22 ± 4.85) s, F1 were (50.47 ± 3.20), (48.25 ± 6.53), (47.13 ± 1.25), (43.72 ± 4.27) and (40.66 ± 4.52) s, F2 were (51.31 ± 4.73), (48.88 ± 1.53), (46.56 ± 1.43), (44.25 ± 1.16) and (41.20 ± 3.79) s, F3 were (51.72 ± 3.54), (50.78 ± 4.45), (45.03 ± 3.56), (41.19 ± 5.63) and (42.81 ± 6.29) s, F4 were (53.34 ± 4.60), (52.34 ± 2.77), (48.72 ± 5.92), (46.97 ± 7.38) and (44.94 ± 1.75) s. On the fourth and fifth days of F1, F2, F3 and F4 generations of C3H, the escape latencies between generations were significantly different (all P < 0.05). The times of through target area in the sixth day of the C3H control group and F1, F2, F3 and F4 mice were 2.25, 1.75, 1.63, 1.50 and 1.38, Balb/c were 2.13, 1.75, 1.63, 1.38 and 1.13. Conclusion Arsenic accumulation due to serial passage of C3H and Balb/c through long-term low doses arsenic exposure through drinking water has resulted in decreased learning and memory ability. Key words: Drinking; Arsenic; Serial passage; Maze Learning