Microencapsulated Sertoli cells sustain myoblast proliferation without affecting the myogenic potential. In vitro data

Sertoli cells (SeC) isolated from porcine testes have shown direct effects on muscle precursor cells sustaining C2C12 myoblasts proliferation and inhibiting oxidative stress and apoptosis in the early phase of the differentiation process, and stimulating myoblast fusion into myotubes and the expression of markers of myogenic differentiation in the late phase. This suggested that the cocktail of factors secreted by SeC stimulates proliferation in myoblasts without weakening their myogenic potential resulting in the formation of the critical myoblast amount necessary to rebuild the required muscle mass upon a damage. Here, we show that co-culturing C2C12 myoblasts with high doses of SeC microencapsulated in clinical grade alginate-based microcapsules (MC-SeC) for three days in differentiation medium (DM) translates into increased cell numbers and almost absence of myotube formation. However, after removal of MC-SeC, an intense fusion activity into myotubes was observed culminating in a fusion index similar to that of control after additional three days of culture in DM. These data definitely demonstrate that SeC-derived factors preserve the myogenic potential while sustaining cell proliferation in C2C12 myoblasts.