High PEEP Activates ITGB1, Inducing Diaphragm Fibrosis During Prolonged Mechanical Ventilation

Mechanical ventilation (MV) with high positive end-expiratory pressure (PEEP) is linked to ventilation-induced diaphragm dysfunction (VIDD), but the role of integrin beta-1 (ITGB1) in PEEP-associated diaphragm fibrosis remains unclear.

Eighteen rabbits were divided into control (CON), MV without PEEP(MV), and MV with 8 cmH₂O PEEP (PEEP) groups. C2C12 underwent cyclic stretching (15% tension), and ITGB1 was knocked down. Fibrosis markers (TGFβ-1, α-SMA), ITGB1/ROCK1 expression, and pathway activation were analyzed via RNA sequencing, immunohistochemistry, and Western blotting.

The PEEP group exhibited elevated airway pressure and upregulated fibrosis markers (TGFβ-1 and α-SMA) alongside activated ITGB1/ROCK1 mechanotransduction pathways. Stretched C2C12 showed morphological shrinkage and increased fibrotic protein expression. RNA sequencing confirmed enrichment in fibrosis- and integrin-related pathways. ITGB1 knockdown attenuated TGFβ-1 and α-SMA induction.

ITGB1 mediates PEEP-induced diaphragm fibrosis via TGFβ-1 signaling and collagen deposition, suggesting ITGB1 targeting as a potential therapeutic strategy for VIDD. These findings elucidate the mechanotransduction mechanisms underlying MV-associated diaphragm dysfunction.