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Updated: May 22, 2026
3D Cine Magnetic Resonance Imaging of Respiratory Motion in Mechanically Ventilated Mice and Rats
Published on: September 19, 2025
Mitogen-activated protein kinase phosphatase-1 modulates regional effects of injurious mechanical ventilation in
Moo Suk Park1, Qianbin He, Michael G Edwards
1Division of Pulmonary and Critical Care Medicine, Department of Medicine, Denver Health and University of Colorado, 777 Bannock Street, Denver, CO 80204, USA.
Rationale:
Mechanical ventilation induces heterogeneous lung injury by mitogen-activated protein kinase (MAPK) and nuclear factor-κB. Mechanisms regulating regional injury and protective effects of prone positioning are unclear.
Objectives:
To determine the key regulators of the lung regional protective effects of prone positioning in rodent lungs exposed to injurious ventilation.
Methods:
Adult rats were ventilated with high (18 ml/kg, positive end-expiratory pressure [PEEP] 0) or low Vt (6 ml/kg; PEEP 3 cm H(2)O; 3 h) in supine or prone position. Dorsal-caudal lung mRNA was analyzed by microarray and MAPK phosphatases (MKP)-1 quantitative polymerase chain reaction. MKP-1(-/-) or wild-type mice were ventilated with very high (24 ml/kg; PEEP 0) or low Vt (6-7 ml/kg; PEEP 3 cm H(2)O). The MKP-1 regulator PG490-88 (MRx-108; 0.75 mg/kg) or phosphate-buffered saline was administered preventilation. Injury was assessed by lung mechanics, bronchioalveolar lavage cell counts, protein content, and lung injury scoring. Immunoblotting for MKP-1, and IκBα and cytokine ELISAs were performed on lung lysates.
Measurements And Main Results:
Prone positioning was protective against injurious ventilation in rats. Expression profiling demonstrated MKP-1 20-fold higher in rats ventilated prone rather than supine and regional reduction in p38 and c-jun N-terminal kinase activation. MKP-1(-/-) mice experienced amplified injury. PG490-88 improved static lung compliance and injury scores, reduced bronchioalveolar lavage cell counts and cytokine levels, and induced MKP-1 and IκBα.
Conclusions:
Injurious ventilation induces MAPK in an MKP-1-dependent fashion. Prone positioning is protective and induces MKP-1. PG490-88 induced MKP-1 and was protective against high Vt in a nuclear factor-κB-dependent manner. MKP-1 is a potential target for modulating regional effects of injurious ventilation.
