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.