Effect of tenotomy on metabosensitive afferent fibers from tibialis anterior muscle.

In previous studies, the effect of tenotomy had been focused mainly on muscle properties (typology, capillarity, force, etc.). Little attention was paid to the metabosensitive fibers from groups III and IV (also called 'ergoreceptors' or 'exercise receptors'). In the current study, we assessed the metabosensitive responses in a rat model with tenotomized muscle. Two groups of animals were included: a control group (C, no tenotomy) and a tenotomized group (Tn, transection of the distal tendon of the left tibialis anterior). After 10 weeks, we observed in the Tn group a significant decrease in the metabosensitive afferent responses to electrically induced fatigue and to chemical agents (KCl and lactic acid), known to activate the metabosensitive fibers. These data indicate that (1) tenotomy induces an alteration in the metabosensitive response and consequently modifies the sensory-motor loop; (2) metabosensitive fibers may have a secondary role in tenotomy-induced muscle properties alterations. Additional studies are required to improve our understanding of the metabosensitive responses after tendon or nerve injury.