LIMB LENGTHENING PROMOTES MUSCLE GROWTH

Studies of limb lengthening have demonstrated successful bone formatio n in the distraction gap. Failure of the muscle units to lengthen lead s to many complications that significantly limit the success of this a pproach; it is, therefore, of paramount importance to characterize the behavior of the muscle during limb lengthening. In this study, tibiae of adult rabbits were lengthened for 10 days at a rate of 1 mm/day. T he proliferative ability of the lengthened muscle was characterized us ing bromodeoxyuridine, a thymidine analogue that is incorporated durin g cell division, and desmin, a muscle-specific marker. We observed a l arge number of proliferating cells, specifically in the lengthened mus cle, that were co-localized with many desmin-positive cells. The prese nce of bromodeoxyuridine nuclei inside desmin-positive muscle fibers s uggests that limb lengthening promotes muscle growth by triggering myo blast proliferation and fusion into the lengthened muscle. Our finding s are consistent with those of other studies in the reviewed literatur e that also suggest that limb lengthening promotes muscle growth.