Effect of concurrent administration of granulocyte colony stimulating factor and pirfenidone on experimentally induced lung fibrosis in adult male albino rats (a histological, immunohistochemical & ultrastructural study)

Lung fibrosis is an irreversible life-threatening condition. So, this study directed to investigate the structure of lung tissue following bleomycin-induced pulmonary injury and to evaluate the potential protective effects of pirfenidone, granulocyte colony-stimulating factor (GCSF), and their combined administration. Fifty-six adult rats were allocated into control, bleomycin-treated, pirfenidone-treated, GCSF-treated, and combination groups. Lung specimens were processed and examined using light & transmission electron microscopes beside biochemical examination for MDA and GSH. Bleomycin administration caused marked structural alterations. Both Pirfenidone and GCSF alone resulted in partial improvement of pneumocyte ultrastructure and reduced fibrotic features. Notably, the combined therapy group demonstrated the most evident protection, with near-normal pneumocyte morphology and reduced degenerative changes. These findings suggest that combined pirfenidone and GCSF therapy exerts a synergistic effect in ameliorating bleomycin-induced lung injury at the ultrastructural level.