Partial purification and biochemical characterization by liquid chromatography of specific myo-mitogenic factor(s) from culture medium of activated macrophages

In the damaged tissues, macrophages, besides to remove necrotic tissue, secrete many soluble growth factors. We have recently demonstrated that macrophage conditioned medium displayed a myo-mitogenic activity increasing the myotube yield when added to an in vitro culture of both human and rat myoblasts. In order to partially purify and characterize the factor(s) responsible for this selective growth, the crude macrophage conditioned medium was subjected to affinity chromatography using Sepharose-bonded heparin. A further purification was then achieved by reversed phase chromatography. The biological activity of each Chromatographic fraction was assessed by measuring the effect of their presence on the amount of desmin, a specific muscle marker, expressed in primary muscle cultures. The results obtained indicated that, even though partially, the factor(s) was purified more than 1000-fold.