Modulation of Hippocampal Proteins by Exposure to Simulated Microgravity Environment during the Postnatal Development in Rats

Abstract

Effects of 14 days of hindlimb suspension and 14 days of ambulation recovery on the hippocampus proteome were investigated in 3-week old male Wistar Hannover rats during postnatal developing stage. Hindlimb suspension caused increased and decreased expression of 4 and 6 proteins, respectively. All of these proteins are reported to have functions related to cellular protection, cell death, neurogenesis, neural activity, or neuronal circuitry formation. In order to reveal whether post-translational modifications are altered, we further studied isoelectric point profiles of the 3 proteins (protein disulfide isomerase A3, triosephosphate isomerase 1, and sirtuin 2) involved in cell death or neuronal circuitry formation. Each of the 3 proteins indicated different spot patterns between the control and hindlimb-suspended groups. Furthermore, the altered profiles of proteins were not normalized to the age-matched control levels after 14 days of recovery. These results suggest that hindlimb suspension during the postnatal development of the brain might induce an inappropriate cell survival and abnormal neuronal circuitry, followed by disorder in the hippocampus function.