Abstract: Objective To investigate the effects of intense pulse light(IPL)on the content of collagens and mRNA expression of procollagen in BALB/c mouse skin.Methods The BALB/c mice dorsal skin was irradiated by IPL.Skin specimens were taken at different time points after irradiation.Histopathological changes were observed by hematoxylin-eosin-staining,quantitative assessment of collagenⅠand collagen Ⅲ was performed with immunohistochemical staining,and mRNA expression levels of procollagen were detected by RT-PCR.Results After the irradiation,no obvious change was observed for the staining intensity of collegen at 1 week;however,the thickening of dermis began at 2 week,and continued until 8 week.The staining of collagenⅠand Ⅲ was also stronger in IPL-irradiated regions than in sham-irradiated areas at 2 week(P<0.05).Compared to the sham-irradiated group,the mRNA expression levels of procollagenⅠand Ⅲ were increased from 2 week up to 8 week after IPL irradiation(P<0.05),and this up-regulatory effect of IPL was time-dependent.Conclusion IPL irradiation can stimulate collagen production in mouse dermis.

Key words: Procollagen, Collagen typeⅠ, Collagen typeⅢ, Mice,inbred BALB C, Intense pulse light