Rapamycin Regulates Bleomycin-Induced Lung Damage in SP-C-Deficient Mice

Area of Science:

• Pulmonary Medicine
• Molecular Biology
• Toxicology

Background:

• Distal respiratory epithelium injury is linked to idiopathic lung diseases.
• Mutations in surfactant protein C (SP-C) cause interstitial lung disease (ILD) and pulmonary fibrosis (PF).
• SP-C deficient mice (Sftpc(-/-)) model human SP-C related lung disease.

Purpose of the Study:

• To investigate if rapamycin could reduce bleomycin-induced lung fibrosis in Sftpc(-/-) mice.
• To evaluate rapamycin's efficacy in both preventative and therapeutic settings.
• To assess rapamycin's impact on lung function and inflammatory markers.

Main Methods:

• Bleomycin-induced lung injury model in Sftpc(+/+) and Sftpc(-/-) mice.
• Administration of rapamycin either prophylactically or therapeutically post-injury.
• Assessment of lung fibrosis, survival rates, weight loss, airway resistance, and lung compliance.
• Analysis of Th2 cytokine and INF-γ expression.

Main Results:

• Rapamycin treatment worsened weight loss and decreased survival in both genotypes.
• Rapamycin did not reduce lung fibrosis in either preventative or rescue experiments.
• Rapamycin increased airway resistance and decreased lung compliance in Sftpc(-/-) mice.
• Rapamycin elevated profibrotic Th2 cytokines and reduced INF-γ expression.

Conclusions:

• Rapamycin is ineffective and potentially harmful for treating bleomycin-induced lung fibrosis in SP-C deficient mice.
• Novel therapeutic strategies are necessary for treating SP-C deficient ILD/IPF.
• The study highlights the complex role of immune responses in SP-C related lung fibrosis.