Influence of quercetin and x-ray on collagen synthesis of cultured human keloid-derived fibroblasts.

To investigate the effects of quercetin and X-ray on collagen synthesis of cultured human keloid-derived fibroblast and the mechanism.Collagen synthesis of cultured human keloid and normal fibroblasts were detected by hydroxyproline colorimetric analysis. Immunocytochemical staining was used to investigate collagen I and III expression. mRNA expression of collagen I and III, and transforming growth factor (TGF)-beta 1 were assayed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR.Quercetin inhibited the collagen synthesis of both keloid and normal fibroblasts in a dose-dependent manner. Immunocytochemical staining indicated that collagen I and III were down-regulated by quercetin and X-ray (P < 0.05), particularly collagen I (P < 0.05). mRNA expression of both collagen I and III in quercetin groups significantly decreased compared with that in control group (P < 0.05), especially in the group treated with both quercetin and X-ray (P < 0.01). mRNA level of TGF-beta 1 gene was down-regulated by quercertin (P < 0.05).Quercetin will probably be one of the new medicines which could effectively treat keloid. Quercetin combined with X-ray could reduce the dose of radiation.