Effects of swimming in cold water on lipolysis indicators via fibroblast growth factor-21 in male Wistar rats.

This study aimed to investigate the effects of swimming in cold water on the release of FGF21 from various tissues and its impact on fat metabolism. Twenty Wistar rats were randomly divided into three groups: untrained (C), trained in thermo-neutral water (TN, 30 °C) and trained in cold water (TC, 15 °C). The training groups swam intervals (2-3 min) until exhaustion, 1 min rest, three days a week for six weeks, with 3-6% bodyweight load. The mRNA expression of variables was determined in white fat tissue (WAT), and FGF21 protein was also measured in the liver, brown fat tissue (BAT), serum, and muscle. The experimental protocols resulted in lower body weight gain, associated with reduced WAT volume; the most remarkable improvement was observed in the TC group. Swimming significantly increased FGF21 protein levels in WAT, BAT, and muscle tissues compared to the C group; substantial increases were in the TC group. Changes in FGF21 were highly correlated with the activation of genes involved in fat metabolisms, such as CPT1, CD36, and HSL, and with glycerol in WAT. The findings indicate a positive correlation between swimming in cold water and the activation of genes involved in fat metabolism, possibly through FGF21 production, which was highly correlated with fat-burning genes.

Effect of thyme extract supplementation on lipid peroxidation, antioxidant capacity, PGC-1α content and endurance exercise performance in rats.

BACKGROUND: Athletes have a large extent of oxidant agent production. In the current study, we aimed to determine the influence of thyme extract on the endurance exercise performance, mitochondrial biogenesis, and antioxidant status in rats. METHODS: Twenty male Wistar rats were randomly divided into two groups receiving either normal drinking water (non-supplemented group, n = 10) or thyme extract, 400 mg/kg, (supplemented group, n = 10). Rats in both groups were subjected to endurance treadmill training (27 m/min, 10% grade, 60 min, and 5 days/week for 8 weeks). Finally, to determine the endurance capacity, time to exhaustion treadmill running at 36 m/min speed was assessed. At the end of the endurance capacity test, serum and soleus muscle samples were collected and their superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as well as malondialdehyde (MDA) concentration were measured. Protein expression of PGC-1α, as a marker of mitochondrial biogenesis, was also determined in the soleus muscle tissue by immunoblotting assay. RESULTS: Findings revealed that the exhaustive running time in the treatment group was significantly (p < 0.05) prolonged. Both serum and soleus muscle MDA levels, as an index of lipid peroxidation, had a threefold increase in the thyme extract supplemented group (t18 = 8.11, p < 0.01; t18 = 4.98, p < 0.01 respectively). The activities of SOD and GPx of the soleus muscle were significantly (p < 0.05) higher in the non-supplemented group, while there was no significant difference in serum SOD, GPx activities, and total antioxidant capacity between groups. Furthermore, thyme supplementation significantly (p < 0.05) decreased PGC-1α expression. CONCLUSIONS: Thyme extract supplementation increased endurance exercise tolerance in intact animals, although decrease of oxidative stress and regulation of the PGC-1α protein expression are not considered as underlying molecular mechanisms.

Protection of Hippocampal CA1 Neurons Against Ischemia/Reperfusion Injury by Exercise Preconditioning via Modulation of Bax/Bcl-2 Ratio and Prevention of Caspase-3 Activation.

INTRODUCTION: Ischemia leads to loss of neurons by apoptosis in specific brain regions, especially in the hippocampus. The purpose of this study was investigating the effects of exercise preconditioning on expression of Bax, Bcl-2, and caspase-3 proteins in hippocampal CA1 neurons after induction of cerebral ischemia. METHODS: Male rats weighing 260-300 g were randomly allocated into three groups (sham, exercise, and ischemia). The rats in exercise group were trained to run on a treadmill 5 days a week for 4 weeks. Ischemia was induced by the occlusion of both common carotid arteries (CCAs) for 20 min. Levels of expression of Bax, Bcl-2, and caspase-3 proteins in CA1 area of hippocampus were determined by immunohistochemical staining . RESULTS: The number of active caspase-3-positive neurons in CA1 area were significantly increased in ischemia group, compared to sham-operated group (P<0.001), and exercise preconditioning significantly reduced the ischemia/reperfusion-induced caspase-3 activation, compared to the ischemia group (P<0.05). Also, results indicated a significant increase in Bax/Bcl-2 ratio in ischemia group, compared to sham-operated group (P<0.001). DISCUSSION: This study indicated that exercise has a neuroprotective effects against cerebral ischemia when used as preconditioning stimuli.