Figure 1. S100A9KOxTg crossbred mice showed significant improvement in spatial reference memory.

We performed memory tests at the age of 13-months. (A) The Morris water maze test was performed. Training trials were conducted for 5 consecutive days. From the 5^th day of training trials, escape latency was significantly increased in the WT/Tg group. However, the latency was decreased in the KO/Tg group compared to the WT/Tg group.*p<0.05 by one-way ANOVA. (B) The probe test was performed 48 h after the final training session. The times that the mice of each group stayed in zones 1, 2, 3 and 4 were compared. The time spent in the platform quadrant (zone 4) was significantly decreased in the WT/Tg group. However, the KO/Tg group showed memory improvement compared to the WT/Tg group in zone 4. (C) In the Y-maze, the WT/Tg group showed a significant decrease in the alternation rate of arm entries. In the passive avoidance test, the latency time of the KO/Tg group was greatly increased. Behavior task groups were as follows: n = 7–11 per group. These results were analyzed by ANOVA followed by the LSD test *p<0.05, **p<0.01.