Unità Operativa di Fisiologia Clinica, CRC-CeSI, Fondazione "G. d'Annunzio", Chieti-Pescara

Istituto Interuniversitario di Miologia, Università"G. d'Annunzio", Chieti-Pescara

The neuromuscular electrical stimulation (NMES) has been acknowledged as an efficient modality leading to significant improvements in isometric maximal voluntary strength, while the effects of NMES on muscle fatigability are still poorly understood and required further investigations. NMES is also employed in rehabilitation protocols to treat muscle atrophy deriving by different physiological (sarcopenia) or pathological (disuse, cachexia., ecc..) reasons in which, however, the regenerative skeletal muscle system is involved. Aims of this paper is to analyze the behavior of the regenerative system of the VL muscle (satellite cell pool) after NMES training in a 64 years old, healthy (but sarcopenic), volunteer. Training consisting in 24 sessions during 8 weeks to 18 min per session (40 contractions 6.25 seconds each) Parameters were: frequency 75 hz; pulse duration 400 msec; intensity variable set at 60% maximal isometric voluntary contraction. Needle biopsies (4-10 mg) were taken on VL muscle before and after the training. Results: The NMES actived recruitment of satellite cells that showed a very high proliferative rate with a pdl index higher than the control. The recruitment and the activation of satellite cells is also demonstrated by the presence of a greater number of myocytes (and probably fibers) pax-7 positive. In additions, very interesting data derived from antioxidant scavenger system analysis which not only was activated by NMES but was also able to offer synergies with the presence of natural antioxidants such as cranberry extract. Molecular analysis of transcriptome seems to confirm this scenario.