Abstract: Objective: To investigate the effect of intradermal injection of fetal dermal fibroblasts (FBS) cultured in vitro on the photoaged dorsal skin of mice. Methods: The dermal fibroblasts were isolated and cultured from 10 BALB/c mouse embryo skins（E18.5）in vitro for two days. The living cells were labeled with CM-Dil dye to track the survival of FBs at the injection site. Twenty BALB/C male mice were randomly divided into 4 groups with 5 mice in each group: untreated group, model group (treated with ultraviolet), blank group (treated with ultraviolet +PBs injection) and treatment group (treated with ultraviolet +FBs). The effect of fetal FBs on skin photoaging was evaluated by the thickness of dermis and epidermis and the expression level of procollagen type IC-terminal propeptide (PICP). Results:  FBS of fetal mice were mostly shuttle type or irregular triangle, with oval nucleus in the center. The number of CM-Dil-labeled cells was largest on the 3rd day post-injection. The dermis thickness of the treatment group was significantly thicker than that of the blank group(243.659±6.214μm vs.126.198±12.352μm) (P<0.05). The concentration of PICP in the treatment group (120.357±10.260) ng/mL was higher than that in the blank group (95.357±13.471) ng/mL with a significant difference (P<0.05). Conclusion: Intradermal injection of fetal FBS can improve the skin photoaging induced by ultraviolet in mice.

Key words: fibroblasts, skin aging, intradermal injection, cell therapy