Effect of mitochondria transplantation on biochemical properties in spatial learning and memory. (A), swimming latency in navigation test. (B), swimming speed in the three groups. (C), representative swimming route of animals in probe test. In addition, time spent (D) and distance swum (E) in target quadrant increased in probe test after mitochondrial transplantation. The data were expressed as mean ± SEM (n = 10 for each group). The group difference was counted by one-way analysis of variance (ANOVA). ## p < 0.01 compared to young control, and *p < 0.05, **p < 0.01 with aged group.