# The Critical Role of Steroid Regimen for Lung Repair in Experimental Diffuse Alveolar Damage

## TL;DR

This study shows that the timing and regimen of steroid use significantly impact lung recovery in a mouse model of ARDS.

## Contribution

The study introduces a new understanding of how steroid administration regimens affect lung repair in ARDS.

## Key findings

- Repeated dexamethasone doses restored lung function and tissue in mice with ARDS/DAD.
- Single doses or prolonged-release steroids failed to promote full recovery and sometimes worsened lung injury.

## Abstract

Acute respiratory distress syndrome (ARDS) is a common condition among intensive care unit patients and is associated with high mortality. Currently, there are no unified therapeutic strategies, including for the use of systemic glucocorticosteroid (GCS) therapy, in the management of ARDS of various etiologies. Using our previously developed non-surgical and reproducible model of unilateral total diffuse alveolar damage (ARDS/DAD) in the left lung of ICR mice, we investigated the effects of GCS with different durations of action and administration regimens on lung function recovery. Our data show that repeated-course administration of dexamethasone promoted complete normalization of respiratory function, as well as restoration of aeration and perfusion of the left lung in mice following ARDS/DAD induction. In contrast, a single administration of the same drug or the use of a prolonged-release formulation, despite exhibiting anti-inflammatory effects, did not provide adequate lung tissue recovery and, in some cases, even exacerbated injury. These results underscore that in ARDS therapy, not just the use but the specific dosing regimen of glucocorticoids is critically important for driving complete functional and structural lung repair.