The purpose of the present study was to examine myocardial antioxidant and oxidative stress changes in male and female rats in the presence of physiological sex hormone concentrations and after castration. Twenty-four 9-week-old Wistar rats were divided into four groups of 6 animals each: 1) sham-operated females, 2) castrated females, 3) sham-operated males, and 4) castrated males. When testosterone and estrogen levels were measured by radioimmunoassay, significant differences were observed between the castrated and control groups (both males and females), demonstrating the success of castration. Progesterone and catalase levels did not change in any group. Control male rats had higher levels of glutathione peroxidase (50%) and lower levels of superoxide dismutase (SOD, 14%) than females. Control females presented increased levels of SOD as compared to the other groups. After castration, SOD activity decreased by 29% in the female group and by 14% in the male group as compared to their respective controls. Lipid peroxidation (LPO) was assessed to evaluate oxidative damage to cardiac membranes by two different methods, i.e., TBARS and chemiluminescence. LPO was higher in male controls compared to female controls when evaluated by both methods, TBARS (360%) and chemiluminescence (46%). Castration induced a 200% increase in myocardial damage in females as determined by TBARS and a 20% increase as determined by chemiluminescence. In males, castration did not change LPO levels. These data suggest that estrogen may have an antioxidant role in heart muscle, while testosterone does not.
In 8 trained subjects (T) and 9 untrained subjects (UT), lipid peroxidation (LPO), total antioxidant capacity (TRAP), superoxide dismutase, catalase, and glutathione peroxidase (GPx) activities were measured in the blood before and after three different intensities of exercise on the treadmill, determined from ventilatory threshold and maximal oxygen uptake data, obtained from a maximal aerobic power test. In plasma, LPO decreased from 3589 +/- 193 to 3274 +/- 223 cps x mg Hb(-1) (p < 0.05), and TRAP increased from 304 +/- 45 to 384 +/- 57 micromol x L(-1) trolox (p < 0.05) after high intensity exercise in T. GPx activity increased in the T group as compared to the UT group, after exercise in moderate (25.90 +/- 3.79 to 15.05 +/- 3.23 nM x min(-1) x mg protein(-1)) and high (21.75 +/- 4.91 to 12.1 +/- 2.46 nM x min(-1) x mg protein(-1)) intensities (p < 0.05). Superoxide dismutase activity increased after exercise at low (8.35 +/- 0.85 to 9.23 +/- 1.03 U SOD x mg protein(-1)) and moderate (8.89 +/- 0.98 to 10.44 +/- 0.86 U SOD x mg protein(-1)) intensity in UT (p < 0.05). There were no changes in catalase activity. These findings indicate that exercise in this model did not increase lipid peroxidation, probably because of the alterations in TRAP and enzymatic antioxidants.
Early-life environmental events that disrupt the mother-pup relationship may induce profound long-lasting changes on several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces sexual behavior and induces anovulatory estrous cycles in female rats. On the afternoon of proestrus, neonatally handled females show a reduced surge of luteinizing hormone (LH) and an increased content of gonadotropin-releasing hormone in the medial preoptic area (MPOA). In order to detect the possible causes for the reduced ovulation and sexual behavior, the present study aimed to analyze the effects of neonatal handling on noradrenaline (NA) and nitric oxide (NO) levels in the MPOA on the afternoon of proestrus. Neonatal handling reduced MHPG (NA metabolite) levels and MHPG/NA ratio in the MPOA, indicating decreased NAergic activity. Additionally, neonatal handling decreased NO levels, as measured by the metabolites (NOx), nitrite and nitrate in the same period. We may conclude that the neonatal handling procedure decreased activity of the NAergic and NOergic systems in the MPOA during proestrus, which is involved in the control of LH and FSH secretion, and this may possibly explain the anovulatory estrous cycles and reduced sexual behavior of the neonatally handled female rats.
The purpose of the present study was to investigate the effects of experimental diabetes on the oxidant and antioxidant status of latissimus dorsi (LD) muscles of male Wistar rats (220 ± 5 g, N = 11). Shortterm (5 days) diabetes was induced by a single injection of streptozotocin (STZ, 50 mg/kg, iv; glycemia >300 mg/dl). LD muscle of STZdiabetic rats presented higher levels of thiobarbituric acid reactive substances (TBARS) and chemiluminescence (0.36 ± 0.02 nmol/mg protein and 14706 ± 1581 cps/mg protein) than LD muscle of normal rats (0.23 ± 0.04 nmol/mg protein and 7389 ± 1355 cps/mg protein). Diabetes induced a 92% increase in catalase and a 27% increase in glutathione S-transferase activities in LD muscle. Glutathione peroxidase activity was reduced (58%) in STZ-diabetic rats and superoxide dismutase activity was similar in LD muscle of both groups. A positive correlation was obtained between catalase activity and the oxidative stress of LD, as evaluated in terms of TBARS (r = 0.78) and by chemiluminescence (r = 0.89). Catalase activity also correlated inversely with glutathione peroxidase activity (r = 0.79). These data suggest that an increased oxidative stress in LD muscle of diabetic rats may be related to skeletal muscle myopathy. Key wordsReactive oxygen species (ROS) have been implicated in the pathophysiology of a large number of diseases and this role has been attributed to their high reactivity and deleterious effects on cell structures (1,2).Mechanisms that contribute to the high level of oxidative stress in diabetes may include not only increased non-enzymatic glycosylation (glycation) and auto-oxidative glycosylation but also metabolic stress in sorbitol pathway activity, changes in the levels of inflammatory mediators and in the status of antioxidant defense systems (1). Although diabetes has profound effects on the biochemical, morphological and contractile properties of skeletal and cardiac muscle (3), the importance of oxidative stress and its antioxidant adaptations in skeletal muscle of diabetic rats has been less studied.Latissimus dorsi (LD) muscles are used in cardiomyoplasties. Studies have demonstrated that the improvement in cardiac and hemodynamic function in cardiomyoplasty is currently confronted by the occurrence of
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.