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

Abstract

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. 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. 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.