Fig. 5.

Lead impairs spontaneous alternation and increases repetitive arm entry in lead-treated ApoE4-KI females. Spontaneous alternation was assessed using the T-maze at 12–13 months of age. a There was a significant main effect of genotype on spontaneous alternation in females (Two-way ANOVA: genotype, F_(1,32) = 7.666, p = 0.0093). Lead-treated ApoE4-KI female mice exhibited reduced spontaneous alternation compared to female ApoE4-KI control mice (Holm-Sidak post-test: F_(1,32) =2.356, p =0.0490). b There was a significant main effect of both genotype and treatment on repetitive arm entries in females (Two-way ANOVA: genotype, F_(1,32) = 5.915, p =0.0208; treatment, F_(1,32) = 6.164, p =0.0185). ApoE4-KI females exposed to lead exhibited significantly increased repetitive arm entries compared to control ApoE4-KI female mice (Holm-Sidak post-test: F_(1,32) = 2.584, p 0.0289). There was no significant difference in spontaneous alternation or arm re-entries in lead-treated ApoE3-KI and ApoE4-KI male mice. c Female and male mice did not exhibit any arm preference. d There was a significant main effect of genotype on mean session duration in both the females and males, with ApoE4-KI mice completing the alternation task slightly faster than ApoE3-KI mice of the same sex (Two-way ANOVA: females, F_(1,30) = 19.50, p = 0.0001; males F_(1,41) =9.803, p = 0.0032). There was no significant difference in mean session duration between control and lead-treated animals of the same genotype and sex. Data are mean ± SEM with n = 8–13 per sex/genotype/treatment. n.s. not significant; * p < 0.05