Figure 3.

Exercise reduces anxiety and improves contextual discrimination in LCN2-null mice, by increasing the generation of newborn mature neurons. (a) Anxiety assessment in the novelty-suppressed feeding paradigm showed that sedentary LCN2-null mice take longer time to feed, which is decreased after voluntary running (n = 6–10 mice per group). No differences between groups in appetite drive were observed. (b) Freezing behaviour during the training session, represented as the total percentage of freezing and as the progressive increased freezing acquired along the trials of light/shock presentation (Block I-III representing the three light-shock pairings), was similar between groups (n = 6–10 mice per group). (c) Impaired contextual retrieval in context A by sedentary LCN2-null mice is rescued by exercise. (d) Discrimination index affected by the absence of LCN2 is re-established after housing LCN2-null mice with running wheels. (e) Quantitative analysis of the number of newborn mature neurons at DG revealed that exercise promoted a significant increase in both Wt and LCN2-null mice (n = 5 mice per group). (f) Representative images of Calbindin (Calb) and BrdU immunostaining at DG (indicated by white arrows). Scale bar, 100 μm. Data from the sedentary animals is the same as described in Ferreira et al.⁹, and are presented as mean ± SEM and were analyzed by two-way ANOVA with Bonferroni’s multiple comparison test. *Denotes differences between sedentary Wt and LCN2-null mice; ^δbetween sedentary and running Wt; ^#between sedentary and running LCN2-null mice. *^,#p ≤ 0.05, **^,##p ≤ 0.01, ^δδδp ≤ 0.001.