Interleukin-10- and corticosteroid-induced reduction in type I procollagen in a human ex vivo scar culture

Fibroblasts act as the effector cells of the fibrotic response via production of collagen. In an attempt to understand the regulation of fibroblasts from areas of active human tissue fibrosis, we have developed an ex vivo model in which biopsies of scars from patients 6 weeks post thoracotomy were cultured. This model has been used to investigate whether interleukin-10 (IL-10) and triamcinolone acetonide modulate the expression of type I procollagen mRNA and protein. In situ hybridization and a quantitative competitive RT-PCR were used to measure type I procollagen mRNA. Type I procollagen protein was evaluated by immunochemistry. Viability of biopsies in culture using ³H-uridine incorporation into RNA was observed to be > 80% for at least 96 hours. Following addition of either IL-10 or triamcinolone acetonide there was a modest but significant decrease ( P <0.05) in type I procollagen mRNA expression. Similarly, each agent added individually to biopsies reduced the proportion of cells staining positively for type I procollagen when compared to biopsies treated with medium alone ( P <0.05). These results extend in vitro data that IL-10 and corticosteroids down-regulate collagen synthesis in skin fibroblast cell lines and suggest that this ex vivo model may offer a closer approximation to the post-operative scarring process when testing new therapeutic agents for reducing an over-exuberent fibrotic response.