ObjectiveTo investigate the effecs of Lactobacillus rhamnosus on behavior and motor ability of postpartum depression-like mice.

MethodsThe model of postpartum depression(PPD) was established using dexamethasone sodium phosphate during pregnancy in mice.Twenty-five pregnant mice were randomly divided into the low dose group(group Ⅰ), high dose group (group Ⅱ), positive control group(group Ⅲ), model control group(group Ⅳ) and blank control group(group Ⅴ).All mice were intervened by intragastric administration of drugs.The group Ⅰ and group Ⅱ were intervened using 1×10⁷ and 1×10⁸ CFU(kg·d) of Lactobacillus rhamnosus, respectively, the group Ⅲ were intervened using 1.8 mg·kg^-1·d^-1 of paroxetine, and the group Ⅳ and group Ⅴ mice were intervened using the same amount of 0.9% sodiun chloride solution for 4 weeks.The behaviors of mice in each group were tested using 24-hour food consumption experiment, black-and-white box experiment, forced swimming experiment and tail suspension experiment.

ResultsThe differences of the intake, body mass change rate, white box stay time and black-white box shuttle times, duration of immobility and time of suspension tail immobility among five groups were not statistically significant before making model(P>0.05).Compared with before making model, the rats' intake decreased, and the rate of body mass change increased after making model and intervention(P < 0.05).After making model and intervention, the duration of forced swimming and time of suspension tail immobility increased in group Ⅰ, group Ⅱ, group Ⅲ and group Ⅳ.Compared with after making model, the body mass change rate of mice in the intervention group increased(P < 0.05), and the duration of forced swimming and tail suspension immobility decreased in the group Ⅰ, group Ⅱ and group Ⅲ after intervention.Compared with group Ⅴ after making model, the number of black-white box shuttle in other groups decreased, and the time of suspension tail immobility was significantly increased(P < 0.05).After intervention, the differences of the number of black-white box shuttle among five groups were not statistically significnat(P>0.05).Compared with group Ⅴ after intervention, the suspension tail immobile time in other groups increased(P < 0.01).Compared with group Ⅳ after intervention, the suspension tail immobile time in the group Ⅰ, group Ⅱ and group Ⅲ decreased(P < 0.01).

ConclusionsThe female mice treated with dexamethasone sodium phosphate during pregnancy show postpartum depression-like behavior, and Lactobacillus rhamnosus intervention can improve the postpartum anxiety, depression and exercise ability of postnatal mice.