Methotrexate (MTX), an anti-metabolite and anti-inflammatory
drug, has been used to effectively manage and prevent
keloids, but its mechanism(s) of action has not been elucidated. Our study sought to evaluate the effect of MTX on the production of key extra cellular matrix components,
collagen, and
matrix metalloproteinase-1 (MMP-1), produced by fibroblasts and involved in development of
fibrosis. The proliferation and viability of cultured human dermal fibroblasts in response to different concentrations of MTX were determined using cell counting and MTT assay, respectively. Western blot analysis was used to determine the levels of both intracellular and secreted
type 1 collagen and MMP-1. The results showed no significant changes in the proliferation of fibroblasts treated with 50 ng/ml of MTX as compared to that of control. Under the same experimental conditions, the level of secreted and intracellular
type I collagen was markedly reduced and, conversely, the level of MMP-1 increased in treated neonatal, adult, and
hypertrophic scar fibroblasts as compared with those of controls. The possible involvement of MTX-induced
extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in MMP-1 production was also studied and the result showed an increase in phosphorylated ERK 1/2 in response to MTX treatment. In summary, the findings of this study revealed that MTX significantly reduced
collagen production in different strains of fibroblasts derived from neonatal, adult, and
hypertrophic scar tissues, while under the same experimental conditions, it increased the expression of MMP-1. As such, our findings validate and identify a potential mechanism through which MTX functions as an anti-fibrogenic factor in treating fibroproliferative disorders.