Liver antioxidant enzyme activities, mRNA abundance, and glutathione (GSH) status were investigated in male Sprague-Dawley rats placed in an enclosure module aboard Space Shuttle STS-63 for 8 d (F, n = 6). F animals were compared to rats housed in an enclosure module on the ground (G, n = 9), which simulated the vibration and temperature conditions associated with launch and flight, and rats kept under conventional ground vivarium conditions in individual cages (V, n = 6). Spaceflight significantly decreased catalase, GSH reductase, and GSH sulfur-transferase activities m the liver (p < .05). Neither enzyme activity nor enzyme protein content of Cu-Zn and Mn superoxide dismutase (SOD) was affected by flight. The relative abundance of mRNA for Cu-Zn SOD and catalase was significantly decreased comparing F with G rats (p < 05). Spaceflight resulted in a dramatic decrease of liver GSH, glutathione disulfide, and total GSH contents (p < .01), which were accompanied by a lower γ-glutamyl transpeptidase activity (p < 05). F rats showed a 47% (p < .05) increase in liver malondialdehyde concentration compared to G and V rats. Liver protein content was not affected by flight These results indicate that spaceflight can downregulate antioxidant defense capacity and elicit an oxidative stress in the liver.
Bibliographical noteFunding Information:
This study was supported in part by a PHS Grant DK 42034. John Hollander is a recipient of NIH T32 DK 07765. The cDNA probes for Cu-Zn SOD, Mn SOD, catalase, and GPX were generous gifts of Dr. Ye-Shih Ho, Wayne State University, Detroit, MI. The Cu-Zn SOD and Mn SOD antiobodies were generous gifts of Drs. Keiichiro Suzuki and Naoyuki Taniguchi from the Department of Biochemistry, Osaka University, Japan. The cDNA probe for β-actin was a generous gift of Dr. Stuart Smith, Oakland Children’s Hospital, Oakland, CA.
- Antioxidant enzyme
- Lipid peroxidation