Fig. (1).

Hydrogen water prevented cognitive decline. H₂-water was provided from the age of 1 month (A, C), and from the age of 8 months (B). The mice were subjected to the first objection recognition task (ORT) at the age of 14 months (A, B, 14-month-old) and the second ORT at the age of 18 months (A, B, 18-month-old). The recognition indexes were obtained as the frequency (%) of exploring and/or sniffing the object that would be replaced or the novel one that had been replaced. ΔRecognition index (%) indicates the frequencies in Retention test of ORT after the subtraction of those in Training test (background). WT, wild-type; (DAL, H₂-), DAL101 mice drinking degassed control water; (DAL, H₂+), DAL101 mice drinking hydrogen water. Data are shown as the mean ± SEM. n = 9, *p < 0.05, **p < 0.01 by Student’s t-test. (C) The mice were subjected to a passive avoidance task. Step-through latencies before and after the electric shock are obtained and ΔStep-through latency (s) indicates the subtraction of Step-through latencies after from before the electric shock. WT, wild-type (n = 10); DAL, H₂-, DAL101 mice receiving degassed control water (n = 8); and DAL, H₂+, DAL101 mice receiving H₂-water (n = 8). Data are shown as the mean ± SEM. *p < 0.05.