Protective role of 17-b-estradiol toward IL-6 leukocyte expression triggered by intense training in elite young female athletes

Exercise performed at a competitive level could deeply modify the immune system and the cytokine response of athletes. In this report, we demonstrated that young elite female athletes, engaged in synchronized swimming and artistic gymnastics, showed an increase of interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) mRNAs expression of blood mononuclear cells, in comparison to young girls performing sport at a recreational level. The increase of IL-6 and TNF-α mRNAs directly depended on the intensity of the training. L-6 gene expression appeared to be modulated by the levels of circulating oestrogens and pre-pubertal girls revealed higher increases of IL-6. In addition, BMI (body mass index) percentile was inversely correlated with both the increases of IL-6 and TNF-α in pre-pubertal athletes. The consequence of these events was the shift of the cytokine profile toward a pro-inflammatory status. IL-6 and TNF-α are able to impair the growth hormone (GH)- insulin growth factor -1 (IGF-1) axis. Therefore, these modifications induced by training performed at an elite level risk to negatively affect the growth of female children athletes.