Microgravity is known to produce a number of neurological disturbances during
space flight; however, the underlying mechanism of these disturbances is yet to be elucidated. There have been some
reports about the increased
oxidative stress under
microgravity or simulated
microgravity. In the present study, we investigated the process of
oxidative stress induced by simulated
microgravity in different areas of
rat brain, which may shed
light on the mechanism of neurological disturbances and further neuroprotective
research in
spaceflight. After adaption for 7 d, 40 healthy
male Sprague-Dawley rats were matched for
body weight and randomly assigned to
control groups (7, 14, 21 and 28 d) and
tail-suspended simulated
microgravity groups (7, 14, 21 and 28 d). The
tail-suspended groups were treated with 30 angels of
tail suspension and the
control groups were treated similarly to the
tail-suspended groups but without
tail suspension. After the required times, different structures of
rat brain, including
cerebellum,
cerebral cortex and
hippocampus, were harvested and frozen for the further
determination. Griess assay, thiobarbituric
acid reactive substance (
TBARS) assay, competitive
ELISA and ferric reducing
ability of
plasma (FRAP) assay were used for the
observation of the changes of
reactive nitrogen species (RNS),
malondialdehyde (MDA), nitrotyrosine (NT) and total
antioxidant capacity (TAC), respectively. As shown in the results, there were different changes in various
brain regions after
tail suspension compared with
control groups. (1) In
cerebellum, NT increased after 7 d
tail suspension, decreased after 14 d and increased again after 28 d; MDA increased after 14 d; RNS increased and TAC decreased after
tail suspension for 21 d; (2) Increase of NT after14 d
tail suspension, increase of MDA and decrease of TAC after 21 d were found in
cerebral cortex; (3) In
hippocampus, RNS increased after
tail suspension for 7 d, decreased after 14 d and increased again after 28 d; MDA increased after 21 d; NT increased after 28 d; TAC increased after 7 d and recovered after 21 d. These results suggest that simulated
microgravity induced by
tail suspension increases the level of
oxidative stress in
rat brain; however, there are different features in different areas of
rat brain. During the response to simulated
microgravity,
rat brain tissues present a
similar process from adaptive response to irreversible
oxidative damage.