Fractional CO2 laser combined with 595-nm PDL inhibiting hypertrophic scars via measuring BMP-7 and Fas expression in rabbit models

Abstract Background and ObjectivesAlthough the treatment of hypertrophic scar (HS) remain challenging, fractional CO2 laser (FCO2L) and 595-nm pulsed-dye laser (PDL) have proved clinical efficacy. Meanwhile, BMP-7 and Fas proteins are demonstrated to promote wound healing and inhibit scar formation, yet few reports on the effect of the two proteins on hypertrophic scarring are available, and their molecular mechanisms remain unclear. In current study, we attempted to observe the effect of combined use of FCO2L with 595-nm PDL in HS animal models through determining the expression of BMP-7 and Fas in scar inhibition.Materials and MethodsTwenty New Zealand white rabbits were randomized to control group, FCO2L group, PDL group and combined treatment group. Four HS samples were developed at each ear of individual rabbit. FCO2L was respectively applied to simple FCO2L and combined treatment group, and simple 595-nm PDL and combined treatment group. Totally, 3 sessions of treatments were carried out once every 14 days. Then, the changes of fibroblasts and collagens in HSs and expression of BMP-7 and Fas proteins in the scar tissues were determined via histological and immunohistochemical studies, ELISA, CCK8 test, RT-PCR and Western blot assay.ResultsHSs were flattened and shrunk after treatment, especially in rabbits treated by FCO2L plus 595-nm PDL group, in which obviously decreased abnormal fibroblast and collagen were noted. The deference was significant compared to other groups(P < 0.001). Moreover, expression of BMP-7 and Fas was both increased in the combined treatment group compared to single FCO2L or 595-nm PDL therapy group (P < 0.001) .ConclusionsFCO2L combined with 595-nm PDL can improve HSs in rabbit models by inhibiting excessive fibroblast growth and collagen deposition. This may be associated with increased BMP-7 and Fas expression in the scar tissues. And our findings may pioneer a new therapeutic strategy for alternative treatment of HSs.