Serial Histologic and Immunohistochemical Changes in Anterior Digastric Myocytes in Response to Distraction Osteogenesis

Skeletal and Soft Tissue Response to Automated, Continuous, Curvilinear Distraction Osteogenesis

“…Within previous studies of discontinuous DO at 1 mm/day, we demonstrated a return to a quiescent state of muscle at end-fixation. [32]. This indicates termination of myocyte proliferation in response to DO within the surrounding digastric muscles.…”

“…MyoD and PCNA, indicators of muscle proliferation, showed low signaling for both groups. [32, 37, 38] PAX7, a marker of the quiescent myocyte state, was uniformly expressed throughout. [33–35] This is as expected since this investigation was specifically limited to end-fixation healing in order to demonstrate the feasibility of continous DO at rates greater than 1mm/day.…”

“…DO induces myocyte proliferation leading to increased muscle length and volume in the digastric muscles. [28–32] Contained beneath the basal lamina of myocytes, myogenic stem (satellite) cells lie in a quiescent state maintained by the protein, paired-Box-7-protein (PAX7). [33–35] These satellite cells are responsible for the production of postnatal muscle mass and orchestrate muscle repair.…”

“…[28] Each of the aforementioned proteins will be either upregulated or downregulated depending on the regenerative (active satellite muscle cells) or dormant (inactive satellite muscle cells) state of the muscular tissue. [32] At the termination of the DO fixation period, muscular expansion and expression is expected to return to the baseline. [32]…”

“…[32] At the termination of the DO fixation period, muscular expansion and expression is expected to return to the baseline. [32]…”