Additive effects of physical exercise and environmental enrichment in attenuating alterations in the hippocampal neuronal morphology of adult wistar rats induced by prenatal inflammations

The present study is aimed at elucidating the additive effects of treadmill running exercises and environmental enrichment (E. E) during adolescence in ameliorating the alterations in the dendritic morphology of hippocampal CA3 neurons induced by prenatal inflammations. Pregnant Wistar dams were injected intraperitoneally with either 0.5ml of saline (control group) or lipopolysaccharide (LPS group) (0.5mg/kg), from the embryonic day fourteen till delivery, on alternate days. Following parturition, pups were allocated into following groups [n=6/group]: (1) Control, (2) LPS, (3) LPS-exercise, (4) LPSenvironmental enrichment and (5) LPS-exercise-environmental enrichment. On postnatal days fifteen to sixty, rats of the groups three, four and five were subjected either to treadmill running exercises or environmental enrichment or the combination of the two, respectively. On PND (postnatal day) sixty-seven, animals were euthanized, brains were carefully dissected out, and impregnated with modified Golgi-cox stain. Dendritic arborization of CA3 neurons in hippocampus was traced by camera lucida and analysed by Sholl's method. The young adult rats of LPS-environmental enrichment-exercise group showed a significant enhancement in dendritic arborization of CA3 hippocampal neurons, compared with other groups. Being reared in an intricate and enriched environment supported by treadmill exercises during adolescence enhances the dendritic arborization of hippocampal CA3 neurons that were exposed to LPS-induced prenatal inflammations. This study investigates the effects of using these methods in combination rather than administering either treadmill exercise, or environmental enrichment each on its own.