Proteomic Analysis of Mice Hippocampus in Simulated Microgravity Environment

Abstract

Space travel induces many deleterious effects on the flight crew due to the '0' g environment. The brain experiences a tremendous fluid shift, which is responsible for many of the detrimental changes in physical behavior seen in astronauts. It therefore indicates that the brain may undergo major changes in its protein levels in a '0' g environment to counteract the stress. Analysis of these global changes in proteins may explain to better understand the functioning of brain in a '0' g condition. Toward such an effort, we have screened proteins in the hippocampus of mice kept in simulated microgravity environment for 7 days and have observed a few changes in major proteins as compared to control mice. Essentially, the results show a major loss of proteins in the hippocampus of mice subjected to simulated microgravity. These changes occur in structural proteins such as tubulin, coupled with the loss of proteins involved in metabolism. This preliminary investigation leads to an understanding of the alteration of proteins in the hippocampus in response to the microgravity environment.

Proteomic Analysis of Mouse Hypothalamus under Simulated Microgravity

“…The tissue was at −80°C for further experiments. We have previously used this tail suspension model to simulate microgravity and have shown changes in the proteome of the mouse brain hippocampus [9]. Analysis of the same model also showed changes in cytokine levels and reactive oxygen species in the mouse brain and signaling events linked with ROS [10,13].…”

“…Some of the changes detected using this model were similar to those detected in mice flown in space. The tail suspension method mimics microgravity by causing fluid to shift into the brain similar to what is observed in real space flight conditions [9,10].…”

“…The control mice were maintained in normal cages with free access to drinking water and diet. To simulate microgravity, mice were suspended by their tail in the center of the cage but allowed to touch the floor with their front paws, and left for 7 days with free access to drinking water and food [9,10,13]. At the end of the experiment, the mice were euthanized by carbon dioxide asphyxiation.…”

“…At the end of the experiment, the mice were euthanized by carbon dioxide asphyxiation. Each brain was dissected out as described by our standardized procedures and, the hypothalamus was removed followed by snap frozen in liquid nitrogen [9,10]. The tissue was at −80°C for further experiments.…”

“…Recent studies reported changes in the proteome of the hippocampus in mice subjected to simulated microgravity [9]. These changes included cytoskeleton proteins and proteins involved in metabolism.…”