Figure 4. Female C57BL/6 CR offspring are less affected by MIA than their male littermates.

The young adult female littermates of the males shown in Figure 3 were mostly unaffected by MIA, regardless of BIR group. In contrast to male offspring, there was no difference in grooming behavior (A-C) in any of the female offspring from dams injected with any of the three poly(I:C) doses. (D) The only significant behavioral difference in the female offspring was a decrease in rearing in the offspring from dams with medium BIR injected with 30mg/kg poly(I:C) (Nested one-way ANOVA; F_3,26 = 4.623, P = 0.0305), similar to the changes found in their male littermates (Figure 3D). Female offspring from dams injected with the same dose, but with low or high BIR, and from dams injected with lower (20mg/kg) (E) or higher doses (40mg/kg poly(I:C) (F), were no different from control offspring (Nested one-way ANOVA; 20mg/kg; F_3,26 = 0.1937, Low: P = 0.9849; Medium: P = 0.9693; High: P = 0.9953; 30mg/kg, F_3,26 = 4.623, Low: P = 0.8567; High: P = 0.3447; 40mg/kg; F_3,25 = 2.239, Low: P = 0.3767; Medium: P = 0.9421, High: P = 0.3248). As in the males, MIA does not alter freezing in offspring, although there were stronger trends toward changes in the females than in the males (G-I). 2-6 pups per litter were assessed for behaviors and their responses were averaged into a single value per litter. It is important to note that the variability in control offspring likely contributes to the lack of significant effects in some of these behaviors. Bars represent mean of litter values for 3-12 litters, as indicated ± SEM. Significance was determined using a nested 1-way ANOVA followed by Tukey’s test for multiple comparisons.