effects of physical exercise on object recognition memory in adult rats of postnatal isoflurane exposures

Objective To investigate effects of physical exercise (PE) on object recognition memory in adult rats of postnatal isoflurane (Iso) exposures. Methods One hundred and ten postnatal 7-day SD rats (P7) were randomly divided into four groups: normal control group (Naive), Naive+PE group (received physical exercise in P21: a treadmill exercise 30min each day, 5 times/week, for 6 weeks), Iso group (three times of 2-hour Iso exposure in P7, P9, and P11), and Iso+PE group (received PE in P21 after postnatal Iso exposures). In P67, behavioral testing was conducted including open field and object recognition task (ORT), recording the time (Discrimination Ratios, DR) that rats spent on exploring each object, evaluating effects of PE on object recognition memory. Results There was no significant difference in influence of PE on open field testing in all of the groups (P>0.05). Compared with Naive, there was no group difference in DR (P>0.05) for all groups, but the DR of Iso male rats was significantly higher than that of Naive female rats in P67, with significant difference (P=0.034). Compared with non-PE groups, whether or not postnatal Iso exposures, the DR of PE male groups was significantly higher (compared with Naive and Iso group: P67, P=0.050, P=0.017; P95, P=0.037, P=0.019); in female rats, the DR for ISO+PE group was lower than that of Iso group in P67 (P=0.036), but the DR of Naive+PE group was higher than that of Naive group in P95 (P=0.004). Compared with male rats, the DR of non-PE female rats was significantly higher in P67 (vis. Naive and Iso group: P=0.022, P=0.011); but in P95, the DR of non- Iso female groups was significantly higher than that of male groups (vis. Naive and Naive+PE: P=0.008, P=0.017). Conclusions There is no obvious impact of postnatal Iso exposures on object recognition memory of adult rats. These results also indicate that postnatal PE could improve object recognition memory of non-spatial learning in adult rats. In addition, exercise benefits have gender differences. DOI: 10.11855/j.issn.0577-7402.2017.07.08