Effects of chronic restraint stress and 17-β-estradiol replacement on oxidative stress in the spinal cord of ovariectomized female rats.
Previous studies have shown sex-specific oxidative changes in spinal cord of rats submitted to chronic stress, which may be due to gonadal hormones. Here, we assessed total radical-trapping potential (TRAP), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and lipid peroxidation (evaluated by the TBARS test) in the spinal cord of ovariectomized (OVX) female rats. Female rats were subjected to OVX, and half of the animals received estradiol replacement. Animals were subdivided into controls and chronically stressed (for 40 days). Our findings demonstrate that chronic stress decreased TRAP, and increased SOD activity in spinal cord homogenates from ovariectomized female rats and had no effect on GPx activity. On the other hand, groups receiving 17β-estradiol replacement presented a decreased GPx activity, but no alteration in TRAP and in SOD activity. No differences in the TBARS test were found in any of the groups analyzed. In conclusion, our results support the idea that chronic stress induces an imbalance between SOD and GPx activities, additionally decreasing TRAP. Estradiol replacement did not reverse the effects of chronic stress, but induced a decrease in GPx activity. Therefore, estradiol replacement in ovariectomized chronically stressed rats could make the spinal cord more susceptible to oxidative injury.
Crema
Leonardo M
LM
Programa de Pós-Graduação em Neurociências, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Diehl
Luisa A
LA
Aguiar
Ana P
AP
Almeida
Lúcia
L
Fontella
Fernanda U
FU
Pettenuzzo
Letícia
L
Vendite
Deusa
D
Dalmaz
Carla
C
D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013315:Stress, Psychological / Q000503:physiopathology*; D013482:Superoxide Dismutase / Q000378:metabolism
D004958:Estradiol; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase