High Intensity Physical Exercise before the Brain Ischemia Promotes Increase in Brain Injury.

Studies have demonstrated the beneficial effects of light- and moderate-intensity physical exercise on the nervous system of animals with cerebral ischemia. To investigate the effects of two high-intensity physical exercise protocols, standardized for resistance and strength gain, in rats trained before cerebral ischemia induced by Bilateral Common Carotid Artery Occlusion (BCCAO). Forty-eight male Wistar rats were divided into two groups: with ischemia and without ischemia (sham). Both groups were subdivided into animals that performed high-intensity exercises in the muscle strength modality (I+Ex2; Sham+Ex2; n=16); animals submitted to high-intensity exercises in the aerobic modality (I+Ex1; Sham+Ex1; n=16), and animals that did not practice physical exercises - sedentary (I+Sed; Sham+Sed, n=16). Cerebral ischemia was induced using the BCCAO model. The physical training program used before the procedure was of high intensity, in the aerobic and muscular strength modalities, and was performed using a vertical ladder, for 4 weeks, 5 days per week. In order to process and stain the brain tissue, the Nissl method was used for neuron labeling and quantification in the cortex, striatum, and hippocampus. As for the animals' body weight and the heart weight differences were found between the groups I+Ex2 and Sham+Ex2 (p<0.05). Data on neuron quantification in the cerebral cortex, dentate gyrus, and right and left striatum revealed significant differences between groups. High-intensity physical training in the strength gain modality promotes significant damage to the animal's brain when performed prior to BCCAO-induced cerebral ischemia.

Refeeding abolishes beneficial effects of severe calorie restriction from birth on adipose tissue and glucose homeostasis of adult rats.

OBJECTIVES: Calorie restriction (CR) is an important intervention for reducing adiposity and improving glucose homeostasis. Recently we found that in rats, a severe calorie restriction (SCR) beginning at birth up to adult age promotes positive effects on cardiometabolic risk factors and heart. The aim of this study was to investigate the effects of this new model of SCR on adipose tissue and glucose homeostasis of rats and to evaluate the effects of refeeding. METHODS: From birth to 90 d of age, rats were divided into an ad libitum (AL) group, which had free access to food, and a CR50 group, which had food limited to 50% of that consumed by the AL group. From this moment, half of the CR50 animals had free access to food (the refeeding group [CR50-R]), and the other half continued 50% restricted for an additional 90-d period. Food intake was assessed daily and body weight weekly. In the final week of the SCR/refeeding protocol, oral glucose and intraperitoneal insulin tolerance tests were performed. Thereafter, rats were sacrificed and visceral fat was collected and used for histologic and Western blot analysis. RESULTS: Findings from this study revealed that SCR beginning at birth and up to adult life promoted a large decrease in visceral adiposity; improvement in glucose/insulin tolerance; and upregulation of adipose proliferating cell nuclear antigen, sirtuin 1, peroxisome proliferator-activated receptor-γ, and adiponectin. Refeeding abolished all of these effects. SCR from birth to adult age promoted beneficial effects on adipose tissue and glucose homeostasis; whereas refeeding abolished these effects.