Abstract:

Objective To observe the influence of sub-chronical exposure to lead and benzo (α) pyrene (B［α］P) on mouse behaviors, calcium ion concentration and ATPase of hippocampus, and to explore joint toxical effects on the possible mechanisms of neurobehavioral toxicity. Methods Eighty mice were randomly divided into five groups (n=16): the blank control group, solvent control group (vegetable oil), lead group (54 mg/L lead acetate), B［α］P group (5 mg/kg B［α］P), and lead+B［α］P group (54 mg/L lead acetate+5 mg/kg B［α］P). Lead acetate dissolved in drinking water was given every day, while B［α］P was administered intraperitoneally four times a week. After being exposed for eight weeks, the learning and memory functions of mice were measured by Morris water maze. The concentration of Ca2+ in hippocampus was detected by fluorescent labeling and the colorimetric technique was used to detect the activity of Na+,K+-ATPase and Ca2+,Mg2+-ATP in hippocampus. Results The results of morris water maze test showed that mice given lead or/and B［α］P exhibited a significant decrease in spacial learning and memory as compared to control groups (P<0.05). Lead+B［α］P group was decreased far more than lead group and B［α］P group (P<0.05). The levels of Na+,K+-ATPase and Ca2+,Mg2+-ATPase of the hippocampus in lead or/and B［α］P group were significantly decreased (P<0.05), while levels of Ca2+ were significantly increased as compared to control groups (P<0.05). The lead+B［α］P group had significantly lower activities of Na+,K+-ATPase and Ca2+,Mg2+-ATPase (P<0.05) and much higher concentration of Ca2+ than those of lead group and B［α］P group (P<0.05). Conclusion The combination of lead and B［α］P can impair the learning and memory functions of mice, and the possible mechanisms of behavioral deficits may be due to increased Ca2+ concentration and the decreased activities of Na+,K+-ATPase and Ca2+,Mg2+-ATPase in the hippocampus.

Key words: benzo (α) pyrene, lead, joint exposure, morris water maze, calcium, ATPase