Aerobic exercise in adolescence results in an increase of neuronal and non-neuronal cells and in mTOR overexpression in the cerebral cortex of rats.

Better cognitive performance and greater cortical and hippocampal volume have been observed in individuals who undertook aerobic exercise during childhood and adolescence. One possible explanation for these beneficial effects is that juvenile physical exercise enables better neural development and hence more cells and neuronal circuitries. It is probable that such effects occur through intracellular signaling proteins associated with cell growth, proliferation and survival. Based on this information, we evaluated the number of neuronal and non-neuronal cells using isotropic fractionation and the expression and activation of intracellular proteins (ERK, CREB, Akt, mTOR and p70S6K) in the cerebral cortex and hippocampal formation of the rats submitted to a physical exercise program on a treadmill during adolescence. Results showed that physical exercise increases the number of neuronal and non-neuronal cortical cells and hippocampal neuronal cells in adolescent rats. Moreover, mTOR overexpression was found in the cortical region of exercised adolescent rats. These findings indicate a significant cellular proliferative effect of aerobic exercise on the cerebral cortex in postnatal development.

Aerobic exercise reduces hippocampal ERK and p38 activation and improves memory of middle-aged rats.

Aging is often accompanied by cognitive decline, memory impairment, and an increased susceptibility to neurodegenerative disorders. Although the physiological processes of aging are not fully understood, these age-related changes have been interpreted by means of various cellular and molecular theories. Among these theories, alterations in the intracellular signaling pathways associated with cell growth, proliferation, and survival have been highlighted. Based on these observations and on recent evidence showing the beneficial effects of exercise on cognitive function in the elderly, we investigated the cell signaling pathways in the hippocampal formation of middle-aged rats (18 months old) submitted to treadmill exercise over 10 days. To do this, we evaluated the hippocampal activation of intracellular signaling proteins linked to cell growth, proliferation, and survival, such as Akt, mTOR, p70S6K, ERK, CREB, and p38. We also explored the cognitive performance (inhibitory avoidance) of middle-aged rats. It was found that physical exercise reduces ERK and p38 activation in the hippocampal formation of aged rats, when compared to the control group. The hippocampal activation and expression of Akt, mTOR, p70S6K, and CREB were not statistically different between the groups. It was also observed that aged rats from the exercise group exhibited better cognitive performance in the inhibitory avoidance task (aversive memory) than aged rats from the control group. Our results indicate that physical exercise reduces intracellular signaling pathways linked to inflammation and cell death (i.e., ERK and p38) and improves memory in middle-aged rats.

Incidência de lesão musculoesquelética sem trauma em atletas de handebol / Incidence of nontraumatic musculoskeletal injuries in handball athletes

O atleta competitivo muitas vezes apresenta lesões musculoesqueléticas, algumas de natureza não traumática. Habitualmente, tais lesões são atribuídas a fatores mecânicos. O presente estudo teve como objetivo estudar um grupo de atletas de handebol e verificar uma possível ação de fatores imune-inflamatórios e hormonais na gênese destas lesões. Procedeu-se à avaliação dos parâmetros laboratoriais, dosando-se a concentração plasmática de hormônios e neurotransmissores e a produção in vitro de citocinas e prostaglandina E2. Os resultados permitem afirmar que em 29% dos atletas estudados foi possível constatar a ocorrência de lesões musculoesqueléticas não traumáticas, que puderam ser relacionadas com o aumento da produção de citocinas pró-inflamatórias, com elevação das concentrações de IL-1, IL-2, TNF-α e IFN-α. Nesta mesma cultura foi possível demonstrar aumento da concentração de prostaglandina E2.

Competitive athletes often present musculoskeletal injuries, some of these nontraumatic. Usually these injuries are attributed to mechanical factors. The present study aimed to investigate a group of handball players and check a possible action of immune-inflammatory and hormonal factors in the genesis of these lesions. Laboratory parameters were studied measuring in the plasma the concentration of plasma hormones and neurotransmitters, and production "in vitro" of cytokines and prostaglandin E2. The results indicate that in 29% of the athletes included in the study the occurrence of nontraumatic musculoskeletal injuries was observed. In this group there was an increased production of pro-inflammatory cytokines assayed in the supernatant of culture of peripheral blood cells with increased concentrations of IL-1, IL-2, TNF-α and IFN-α, as well of prostaglandin E2.