Effects of Dietary Soy Protein on Hematological and Tissue Oxidant/Anti-Oxidant Levels in Rats Exposed to Simulated Microgravity

摘要

Effects of a soy protein diet on oxidant and anti-oxidant levels in selected rodent tissues were investigated under simulated microgravity. Methods: Adult Male Rats were maintained either on a regular Purina Rat chow or on a 9.6% soy protein diet and allowed to remain in either non-suspended (control) or hind-limb-suspended (HLS) state via their tails at a 30 degree angle for 14 days. Body weights, food and water intakes were monitored daily during the entire study period. Hematological parameters, oxidant and. antioxidant levels in the brain, liver and pancreatic tissues were measured. Results: At term, the body weights of the hind limb suspended animals were found significantly decreased when compared with the non-suspended controls, p<0.05. There was no significant change in blood hematocrit and hemoglobin levels. After HLS, malondialdehyde (MDA) levels of brain tissues were marginally increased in the Purina chow group as compared to a significant increase in the soy suspended group (p<0.05). Similar observations were noted with liver and pancreatic tissues. In response to HLS, glutathione levels in brain and pancreatic tissues were increased in the Purina chow group (p<0.05) while in soy group, glutathione (GT) levels in both of these tissues were found relatively lower. Superoxide dismutase (SOD) levels were increased in all three tissues after HLS regardless of the dietary conditions. Conclusions: Data suggest that HLS induced a differential tissue specific oxidative response regardless of the dietary differences. Dietary soy protein lowered the oxidant levels under basal state but their effects were not sustained under HLS conditions significantly.