Fig. 8

Overexpression of lipocalin 2 in the brain induces social avoidance. Single i.c.v. injection of recombinant lipocalin 2 protein (7 μL and 1 μg/mL) or vehicle in the brain of the mice and social interaction behavioral tests were performed after 6 days. A i.c.v. injection position in lateral ventricles (left panel), and the representative heat maps were shown in right panel. The time spent in the interaction zone while the target was present (B) or absent (C). D The social interaction ratio (the time spent in the interaction zone while the target was absent / the time spent in the interaction zone while the target was present). The time spent in corners while the interaction zone with (E) or without (F) the target mice. G The velocity traveled in the target apparatus. Quantitative data are presented as the mean ± SEM (n = 5 each group). The Student’s t-test was used to examine the significance of the mean. * p < 0.05 vs. the vehicle or control groups. i.c.v.: intracerebroventricular, LCN2: lipocalin 2, NS: not significant, SEM: standard error of mean