Abstract
The impact of performing exercise on the immune system presents contrasting effects on health when performed at different intensities. In addition, the consequences of performing chronic exercise have not been sufficiently studied in contrast to the effects of acute bouts of exercise. The porpoise of this work was to determine the effect that a popular exercise regimen (chronic/moderate/aerobic exercise) has on the proportion of different immune cell subsets, their function and if it affects the cannabinoid system with potentially functional implications on the immune system. A marked increase in several immune cell subsets and their expression of cannabinoid receptors was expected, as well as an enhanced proliferative and cytotoxic activity by total splenocytes in exercised animals. For this study male Wistar rats performed treadmill running 5 times a week for a period of 10 weeks, at moderate intensity. Our results showed a significant decrease in lymphocyte subpopulations (CD4+, Tγδ, and CD45 RA+ cells) and an increase in the cannabinoid receptors expression in those same cell. Although functional assays did not reveal any variation in total immunoglobulin production or NK cells cytotoxic activity, proliferative capability of total splenocytes increased in trained rats. Our results further support the notion that exercise affects the immunological system and extends the description of underlying mechanisms mediating such effects. Altogether, our results contribute to the understanding of the benefits of exercise on the practitioner´s general health.
Highlights
The beneficial impact of exercise on the practitioner’s general health is a well-known fact [1,2,3]
Flow cytometry analysis reflected a decrease in the proportion of T helper lymphocytes (Fig 2) and in B lymphocytes (Fig 3) from the EXE group when compared to both control groups, sedentary group (SED) and Treadmill control (TC) (Fig 2 and Fig 3), considering such changes an effect of chronic exercise (CE)
We decided to test the proliferative capacity of the immune cell subpopulations and we found that B lymphocytes and NK cells from the EXE group exhibited a higher proportion of dividing cells than both SED and TC groups (Fig 7D)
Summary
The beneficial impact of exercise on the practitioner’s general health is a well-known fact [1,2,3]. Data regarding the changes induced by exercise in cell subpopulations of the IS and their function seems to be controversial [9,10,11] This may be partly explained by the use of different exercise paradigms. Evidence suggesting a beneficial effect of the performance of exercise, on modalities previously described as detrimental, has been gathered and old data reinterpreted as in Campbell and Turner’s review [12], so nowadays evidence debunking the previous conception of high intensity/ long duration or chronic exercise evoked immune suppression increases, at least for several aspects of the immune function. Likewise, trained rats presented increased glucose consumption, IL-2 production and IL-2R expression by their lymphocytic subpopulations Those changes obtained in trained animals seem to last days after the last exercise bout [14]
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