Effects of a chronic exercise training protocol on oxidative stress and right ventricular hypertrophy in monocrotaline-treated rats.

1. In the present study, we investigated the effects of exercise training on cardiac hypertrophy and oxidative stress in a monocrotaline (MCT)-induced cor pulmonale model. Male Wistar rats were assigned to one of three groups: sedentary control (SC); sedentary MCT (SM); or trained MCT (TM). 2. Right ventricular hypertrophy (RVH) was induced by a single injection of MCT (60 mg/kg, i.p.). Exercise training consisted of running on a treadmill (five times a week, during Weeks 3, 4 and 5). Systemic oxidative stress was evaluated in erythrocytes by chemiluminescence (CL) and the activity of the anti-oxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) was determined. 3. At Week 3, MCT-treated animals exhibited RVH, lung congestion, decreased SOD activity and increased CAT activity. Exercise training reduced MCT-induced RVH and increased GST activity. At Week 4, MCT-induced RVH was accompanied by an increase in CL and GST activity. However, in TM animals there was a decrease in CL and augmented SOD activity. At Week 5, there were no survivors in the SM group, whereas GST activity was elevated in TM rats compared with SC rats. There was no difference in GPx activity throughout the experimental protocol between the groups. 4. Taken together, our results indicate that exercise training is able to ameliorate RVH and improve survival, which is associated with a reduction in oxidative stress in MCT-treated rats.

The clinical impact of preoperative melatonin on postoperative outcomes in patients undergoing abdominal hysterectomy.

BACKGROUND: Melatonin has sedative, analgesic, antiinflammatory, antioxidative, and chronobiotic effects. We determined the impact of oral melatonin premedication on anxiolysis, analgesia, and the potency of the rest/activity circadian rhythm. METHODS: This randomized, double-blind, placebo-controlled study included 33 patients, ASA physical status I-II, undergoing abdominal hysterectomy. Patients were randomly assigned to receive either oral melatonin 5 mg (n = 17) or placebo (n = 16) the night before and 1 h before surgery. The analysis instruments were the Visual Analog Scale, the State-Trait Anxiety Inventory, and the actigraphy. RESULTS: The number of patients that needed to be treated to prevent one additional patient reporting high postoperative anxiety and moderate to intense pain in the first 24 postoperative hours was 2.53 (95% CI, 1.41-12.22) and 2.20 (95% CI, 1.26-8.58), respectively. The number-needed-to-treat was 3 (95% CI, 1.35-5.0) to prevent high postoperative anxiety in patients with moderate to intense pain, when compared with 7.5 (95% CI, 1.36-infinity) in the absence of pain or mild pain. Also, the treated patients required less morphine by patient-controlled analgesia, as assessed by repeated measures ANOVA (F[1,31] = 6.05, P = 0.02). The rest/activity cycle, assessed by actigraphy, showed that the rhythmicity percentual of 24 h was higher in the intervention group in the first week after discharge ([21.16 +/- 8.90] versus placebo [14.00 +/- 7.10]; [t = -2.41, P = 0.02]). CONCLUSIONS: This finding suggested that preoperative melatonin produced clinically relevant anxiolytic and analgesic effects, especially in the first 24 postoperative hours. Also, it improved the recovery of the potency of the rest/activity circadian rhythm.