Diaphragm muscle atrophy in the mouse after long-term mechanical ventilation.

Introduction: Mechanical ventilation (MV) is a life-saving measure, but full ventilator support causes ventilator-induced diaphragm atrophy (VIDA). Previous studies of VIDA have relied on human biopsies or a rat model. If MV can induce diaphragm atrophy in mice, then mechanistic study of VIDA could be explored via genetic manipulation.

Results: We show that 18 hours of MV in mice results in a 15% loss of diaphragm weight and a 17% reduction in fiber cross-sectional area. Important catabolic cascades are activated in this mouse model: transcription of the ubiquitin ligases, atrogin and MuRF1, and the apoptotic marker, Bim, are increased; the marker of autophagy, LC3, is induced at the protein level and shows a punctate distribution in diaphragm muscle fibers.

Conclusions: This mouse model recapitulates the key pathophysiological findings of other models of VIDA, and it will enable the genetic manipulation required to fully explore the mechanisms underlying this important process.