Increased satellite cell apoptosis in vastus lateralis muscle after anterior cruciate ligament reconstruction

Recovery of the quadriceps femoris muscle after anterior ligament reconstruction is im-paired. The aim of this study was to investigate satellite cell content and function of the vastus lateralis muscle after anterior ligament reconstruction. Biopsies were obtained from the vastus lateralis muscle of 16 recreational athletes immediately before and again 12 weeks after anterior ligament reconstruction. Total satellite cell number (Pax7+), activated (Pax7+/MyoD+), differentiating (Pax7-/MyoD+), and apoptotic (Pax7+/TUNEL+) satellite cells, myofibers expressing myosin heavy chain (MHC) I and II, and neonatal MHC (MHCneo) were determined immunohistochemically. After anterior ligament reconstruction, the number of apoptotic satellite cells was significantly (p = 0.019) increased, concomitant with a significant (p