At the same time, the wild-type rats showed a decreasing trend in sucrose preference post CFA injection (pre: 81.57 ± 4.83, post: 67.43 ± 3.88, p > 0.05, paired t-test), whereas the Kcnip3-/- rats showed significantly decreased sucrose preference (pre: 63.86 ± 4.11, post: 44.43 ± 5.47, p < 0.05, paired t-test) post CFA injection compared to that prior to CFA injection, suggesting that Kcnip3-/- rats are more susceptible to depression than wild-type rats. Here, KCNIP3 is linked to major depressive disorder.