(A) MS animals exhibited significantly decreased sucrose preference (F1,16 = 9.16, p < 0.01). There were no sex differences in sucrose preference. (B) We found a trending increase in forced swim test escape time only in male animals (t4 = -2.51, p = 0.066). (C) In the elevated plus maze, male MS animals exhibited a trending increase in closed arm entries (t4 = -2.16, p = 0.097). (D) However, there were no group differences in the anxiety index; data are shown in mean ± standard error of the mean; *p < 0.05;#0.1 > p > 0.05. The relationship between miRNA expression and depressive behavior was shown using Pearson correlations (false discovery rate <0.05). (E) In all animals, percentage sucrose preference inversely correlated with expression of four miRNAs in the amygdala. (F) In males, sucrose preferences correlated positively with prefrontal cortex miR-411-5p and inversely with miR-133b-3p in the amygdala. (G) In females, six miRNAs were correlated with sucrose preference. (H & I) In all animals, four miRNAs were positively correlated (H) and eight were negatively correlated (I) with forced swim escape time. (J) In male animals, 88 miRNAs were significantly (false discovery rate <0.05) correlated with escape time; the top ten miRNAs are shown. Amygdala miRNAs are shown in red hues with square markers, prefrontal cortex in blue hues with circular markers, and hippocampal miRNAs in yellow hues with triangular markers. To aid in visualization, normalized counts per million values were scaled to fit within the same y-axis; therefore relative expression is an arbitrary unit of measure which maintains the slope of each significant correlation.
MS: Maternal separation.