Lipid peroxidation and total radical-trapping potential of the lungs of rats submitted to chronic and sub-chronic stress.
Exposure to stress induces a cluster of physiological and behavioral changes in an effort to maintain the homeostasis of the organism. Long-term exposure to stress, however, has detrimental effects on several cell functions such as the impairment of antioxidant defenses leading to oxidative damage. Oxidative stress is a central feature of many diseases. The lungs are particularly susceptible to lesions by free radicals and pulmonary antioxidant defenses are extensively distributed and include both enzymatic and non-enzymatic systems. The aim of the present study was to determine lipid peroxidation and total radical-trapping potential (TRAP) changes in lungs of rats submitted to different models of chronic stress. Adult male Wistar rats weighing 180-230 g were submitted to different stressors (variable stress, N = 7) or repeated restraint stress for 15 (N = 10) or 40 days (N = 6) and compared to control groups (N = 10 each). Lipid peroxidation levels were assessed by thiobarbituric acid reactive substances (TBARS), and TRAP was measured by the decrease in luminescence using the 2-2'-azo-bis(2-amidinopropane)-luminol system. Chronic variable stress induced a 51% increase in oxidative stress in lungs (control group: 0.037 +/- 0.002; variable stress: 0.056 +/- 0.007, P < 0.01). No difference in TBARS was observed after chronic restraint stress, but a significant 57% increase in TRAP was presented by the group repeatedly restrained for 15 days (control group: 2.48 +/- 0.42; stressed: 3.65 +/- 0.16, P < 0.05). We conclude that different stressors induce different effects on the oxidative status of the organism.
Torres
R L
RL
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 90035-003 Porto Alegre, RS, Brasil.
Torres
I L S
IL
Gamaro
G D
GD
Fontella
F U
FU
Silveira
P P
PP
Moreira
J S R
JS
Lacerda
M
M
Amoretti
J R
JR
Rech
D
D
Dalmaz
C
C
Belló
A A
AA
D000818:Animals; D004195:Disease Models, Animal; D005609:Free Radicals / Q000378:metabolism; D015227:Lipid Peroxidation; D008168:Lung / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism*
D005609:Free Radicals; D017392:Thiobarbituric Acid Reactive Substances