Figure 6.

Three-chamber sociability. Sociability was evaluated using the three-chamber sociability test at 4 and 7 weeks of age. On the first day (trial 1), an examinee rat was acclimated in the three-chamber apparatus. On the second day (trial 2), an examinee rat was allowed to freely visit an empty cage and a cage with a rat. “Rat preference” was calculated as follows: [(time in contact with a rat cage)/(time in contact with a rat cage + an empty cage)] × 100%. Rat preference at 4 and 7 weeks of age in males (A) and females (B). Actual time in contact with an empty cage or a rat cage at 7 weeks of age in males (C) and females (D). On the third day (trial 3), an examinee rat was allowed to freely visit a familiar rat, i.e., a littermate bred in the same animal cage, and an unfamiliar rat. “Unfamiliar rat preference” was calculated as follows: [(time in contact with an unfamiliar rat)/(time in contact with an unfamiliar rat + a familiar rat)] × 100%. Unfamiliar rat preference at 4 and 7 weeks of age in males (E) and females (F). Actual time in contact with a familiar rat or an unfamiliar rat at 7 weeks of age in males (G) and females (H). In the male group: sham-vehicle (n = 5), LBW-vehicle (n = 7), and LBW-MSC (n = 6). In the female group: sham-vehicle (n = 7), LBW-vehicle (n = 17), and LBW-MSC (n = 7). Mean ± standard error of mean. a: p < 0.05, mice in the sham-vehicle vs. LBW-vehicle groups. b: p < 0.05, mice in the sham-vehicle vs. LBW-MSC groups. d: p < 0.05, mice in the LBW-vehicle vs. LBW-MSC groups. *p < 0.05, **p < 0.01 either empty vs. rat cage or familiar vs. unfamiliar rat. LBW, low birth weight; MSC, mesenchymal stromal cell.