Abstract: Hong*, GU Ying, LIU Wei, ZENG Jing, DONG Ning, SUN Ping. *Department of Dermatology, Air Force General Hospital of PLA, Beijing 100142, China Corresponding author: GU Ying, Email: guyinglaser@sina.com 【Abstract】 Objective To observe the phosphorylation of Smad3 in hyperplastic scar fibroblasts （HSFs） induced by hematoporphyrin monomerthyl ether （HMME） followed by photodynamic therapy （PDT）. Methods Fibroblasts were isolated from the hypertrophic scar tissues of 10 patients and subjected to culture in vitro. After 3－5 passages, the HSFs were divided into 4 groups: control group receiving no treatment, PDT group pretreated with HMME of 4 μg/ml followed by PDT, HMME group induced by HMME alone, and laser group irradiated with laser alone. Fluorescence microscopy was used to observe the expression of Smad3 after immunofluorescent staining with anti-Smad3 antibody, and Western blot to detect the expression of Smad3 and phosphorylated Smad3 in these HSFs. Paired t test was conducted to compare the difference in Smad3 and phosphorylated Smad3 expression between these groups. Results The total fluorescence intensity of Smad3 was similar between these groups, but the intranuclear fluorescence signal was significantly weaker in the PDT group than in the control group. The level of phosphorylated Smad3 was statistically decreased in the PDT group compared with the control group （0.20 ± 0.02 vs. 0.92 ± 0.15, P < 0.05）, but no significant difference was observed between the HMME group and laser group （P > 0.05）. Conclusion PDT may inhibit the proliferation of HSFs via attenuating the phosphorylation of Smad3. 【Key words】 Cicatrix, hypertrophic; Fibroblasts; Hematoporphyrin photoradiation; Smad3 protein

Key words: fibrodblast