Imipramine blocks acute silicosis in a mouse model

Area of Science:

• Pulmonary toxicology
• Pharmacology
• Cell biology

Background:

• Silicosis, caused by crystalline silica inhalation, leads to inflammation and lung damage.
• Current treatment options for silicosis are limited.
• Imipramine (IMP), an antidepressant, possesses lysosomotropic properties with potential anti-inflammatory applications.

Purpose of the Study:

• To investigate the efficacy of Imipramine (IMP) in mitigating silica-induced lung inflammation and damage.
• To explore IMP's mechanism in blocking silica-induced phagolysosome membrane permeabilization.

Main Methods:

• In vitro studies assessed alveolar macrophages (AM) exposed to silica and IMP for IL-1β release, cytotoxicity, particle uptake, lysosomal stability, and acid sphingomyelinase activity.
• Short-term in vivo studies in mice evaluated silica-induced inflammation and cytokine release.
• Long-term in vivo studies assessed histopathology, lung damage, and collagen deposition.

Main Results:

• IMP significantly reduced silica-induced cytotoxicity and IL-1β release from AM in vitro.
• In vivo, IMP treatment decreased silica-induced inflammation in a short-term model.
• Long-term studies showed IMP effectively blocked silica-induced lung damage and collagen accumulation.

Conclusions:

• Imipramine exhibits anti-inflammatory properties against silica exposure in both in vitro and in vivo models.
• IMP's therapeutic potential lies in its ability to prevent silica-induced phagolysosomal lysis, cell death, and IL-1β release.
• IMP may serve as a novel therapeutic agent for silicosis and other conditions characterized by phagolysosomal disruption.