Abstract：Objective To explore the effects of embryonic lead exposure on motor function and balance ability in offspring rats and the possible mechanisms. Methods An animal model of embryonic lead exposure was prepared with the use of pregnant Sprague-Dawley rats freely drinking 0.1% (low-dose group, LG) or 0.2% (high-dose group, HG) lead acetate solution. A normal control group (NG) was also set. The male offspring rats of these pregnant rats were included in the study, consisting of 12 rats in the NG group, 10 rats in the LG group, and 9 rats in the HG group. The offspring rats' motor function and balance ability were evaluated using body turning test and coat hanger test. Eight rats were randomly selected from each group, and immunohistochemistry and Timm's staining were employed to measure the expression of c-Fos and mossy fiber sprouting (MFS) in the hippocampus. Results The HG group had a significantly longer body turning time than the NG and LG groups (P < 0.05), and the LG group had a significantly longer body turning time than the NG group (P < 0.05). The HG group had a significantly lower score of balance ability than the NG and LG groups (P < 0.05), and the LG group had a significantly lower score of balance ability than the NG group (P < 0.05). The area percentage of c-Fos-positive neurons in the hippocampal CA1 region was significantly higher in the HG group than in the other two groups (P < 0.05), and it was significantly higher in the LG group than in the NG group (P < 0.05). The semi-quantitative scores of MFS in the hippocampal CA3 region and dentate gyrus were significantly higher in the HG group than in the other two groups (P < 0.05), and they were significantly higher in the LG group than in the NG group (P < 0.05). Conclusions Embryonic lead exposure could impair the offspring rats' motor function and balance ability. These changes may be related to increased c-Fos expression in the hippocampal CA3 region and abnormal MFS in the hippocampal CA3 region and dentate gyrus.
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