An unsafe level of manganese (Mn) was detected in the drinking water in some arsenic (As)-contaminated areas in Bangladesh. Mn is an essential trace element; however, the intake of a higher level of Mn through the drinking water is associated with the development of toxicity in humans. This study was designed to evaluate the effects of As and Mn co-exposure on neurobehavioral and biochemical alterations in a mouse model. Sodium arsenite (10 mg/kg body weight) and manganese chloride tetrahydrate (10 mg/kg body weight) were given to mice individually and in combination with drinking water for 90 days. Results showed that individual As and Mn exposure as well as co-exposure of As and Mn significantly (p < 0.05) reduced the percent of time spent in the open arms when compared with that of control mice. In addition, percent of time spent in open arms significantly (p < 0.05) increased in co-exposed mice compared with As exposure in elevated plus maze (42.05 ± 1.10 versus 38.94 ± 0.66). In the Morris water maze test, the mean time latency to find the platform was longer in metal-treated mice in comparison to that of control mice (p < 0.05). Importantly, the co-exposed group had shorter time when compared with the As-exposed group during the training periods (p < 0.05). Moreover, co-exposed mice stayed significantly (p < 0.05) more time in the target quadrant in the probe trial in comparison with that of As-exposed mice (27.25 ± 1.21 versus 23.83 ± 0.87 s) but less time than control mice (27.25 ± 1.21 versus 43.17 ± 1.49 s). In addition, a significant (p < 0.05) alteration of biochemical parameters such as ALT, AST, ALP, BChE, and SOD as well as urea and creatinine levels were noted in the As-exposed group compared with the control group and Mn significantly (p < 0.05) attenuated the effects of As in co-exposed mice. Therefore, the results of this study suggest that As and Mn may have some antagonistic effect and Mn could attenuate the As-induced neurobehavioral and biochemical alterations in co-exposed mice.
Keywords: Anxiety; Arsenic; Blood indices; Co-exposure; Learning; Manganese; Spatial memory.