Electrophysiologic stimulation improves myogenic potential of muscle precursor cells grown in a 3D collagen scaffold.

The production of engineered three-dimensional (3D) skeletal muscle grafts holds promise for treatment of several diseases. An important factor in the development of such approach involves the capability of preserving myogenicity and regenerative potential during ex vivo culturing. We have previously shown that electrical stimulation of myogenic cells grown in monolayer could improve the differentiation process. Here we investigated the effect of exogenous electrical field, specifically designed to mimic part of the neuronal activity, on muscle precursor cells (MPCs) cultured within 3D collagen scaffolds. Our data showed that electric stimulation did not affect cell viability and increased by 65.6% the release rate of NO(x), an early molecular activator of satellite cells in vivo. NO(x) release rate was decreased by an inhibitor of NO synthase, both in stimulated and non-stimulated cultures, confirming the endocrine origin of the measured NO(x). Importantly, electrical stimulation also increased the expression of two myogenic markers, MyoD and desmin. We also carried out some preliminary experiments aimed at determining the biocompatibility of our seeded collagen scaffolds, implanting them in the tibialis anterior muscles of syngeneic mice. Ten days after transplantation, we could observe the formation of new myofibers both inside the scaffold and at the scaffold/muscle interface. Altogether, our findings indicate that electrical stimulation could be a new strategy for the effective 3D expansion of muscle precursor cells in vitro without losing myogenic potential and that 3D collagen matrices could be a promising tool for delivering myogenic cells in recipient muscles.