Topical cell growth factors for wound healing after fractional CO2 laser therapy: an experimental study

Objective To compare the accelerating effect of topical recombinant human epidermal growth factor （rhEGF） and recombinant bovine basic fibroblast growth factor （rb-bFGF） on wound healing after fractional CO2 laser therapy. Methods Twenty male guinea pigs were included in this study. After hair removal and irradiation with fractional CO2 laser, the back of each guinea pig was divided into 4 regions to be topically treated with rhEGF of 10 μg/cm： （rhEGF group）, rb-bFGF of 262.51 IU/cm2 （rb-bFGF group）, the combination of rhEGF and rb-bFGF （combination group）, or normal saline （control group）, twice daily until the healing of wound. Skin physiology parameters including elasticity index and melanin index were detected before the irradiation, 7, 14 and 28 days after the irradiation, and compared between the 4 groups by analysis of variance. Tissue specimens were obtained from 4 mice at the above time points and subjected to pathological examination for the observation of collagen fibers and quantification of fibroblasts. Results After fractional CO2 laser therapy, the crusts fall off completely in growth factor-treated regions, while partly in the control regions, within 3 to 7 days; the wounds healed completely in 14 to 28 days in all the groups, with the regenerating tissue being more tender and redder compared with the surrounding unirradiated tissue. The wound surface was smaller in area and redder in color in the 3 growth factor-treated groups than in the control group. At 28 days after the irradiation, the elasticity index was 262.29 ± 62.40 in the combination group, 202.00 ± 65.62 in the rhEGF group, 188.86 ± 35.02 in the rb-bFGF group, 167.14 ± 42.49 in the control group. Statistical difference was observed in elasticity index, but not in skin melanin index among the 4 groups. Pathological examination showed a dense and organized arrangement of collagen fibem in the combination group but a sparse and disorganized arrangement of collagen fibers in the control group. Conclusion The combined application of rhEGF and rbbFGF can accelerate the healing of wound and increase the elasticity of regenerating tissue after fractional CO2 laser therapy. Key words: Administration, cutaneous;  Fibroblast growth factor;  Epidermal growth factor;  Lasers;  Wound healing