Mobilisation of satellite cells following ischaemia and reperfusion in primate skeletal muscle

Abstract

Objective. To describe the morphological and morpho- metric features of activated skeletal muscle satellite cells in primates, using an ischaemic reperfusion model. Setting. The study was undertaken at the Biomedical Resource Centre and the Electron Microscopy Unit of the University of KwaZulu-Natal. Interventions. Eight vervet monkeys were anaesthetised and subjected to 3 hours of tourniquet-induced lower limb ischaemia. Open muscle biopsies were taken from tibialis anterior muscle immediately after tourniquet release and 12, 24, 36 and 48 hours after tourniquet release. Control biopsies were taken from the opposite limb. Main outcome measures. Description of the morpholog- ical and morphometric changes in satellite cells after acti- vation, as seen on transmission electron microscopy. Results. Two distinct patterns of satellite cell activation are described. In group 1, the cytoplasm of the satellite cell expands around the myocyte and the gap between the satellite cell and the myocyte appears to break down, or in group 2, the novel observation of the satellite cell breaking away from the myofibre and becoming a myocyte totally encased in its own basal lamina. The satellite cells of group 1 were significantly longer than the group 2 cells (p = 0.018) and this was associated with a significant reduction in the percentage of nuclear to cell area (p = 0.011). Conclusions. Tourniquet-induced ischaemic reperfusion injury is shown to result in two distinct patterns of satellite cell activation which may represent different functions or subsets of satellite cells. C