ABSTRACT
Objective To evaluate the therapeutic effect of long-pulsed Nd:YAG 1064 laser on hyperplastic scars by using a rabbit ear model.Methods Five female and five male New Zealand long-ear white rabbits weighting 2.0-2.5 kg were used in this experiment.Four square full-thickness skin wounds sized 1.5 cm x1.5 cm were created on the ventral surface of each ear to develop a model of hyperplastic scar.Finally,a total of 74 hyperplastic scars developed on the 80 wounds,and the scars on the left and right ears served as the control (unirradiated) and treatment (irradiated with long-pulsed 1064 nm Nd:YAG laser) group,respectively.After 30 days of irradiation,the color and texture of scars were observed and the scar thickness was measured by color Doppler ultrasonogTaphy.Then,the scars were harvested followed by the analysis of density of fibroblasts and microvessels as well as the changes in collagen fibers in scars by HE staining,CD31 staining and Masson staining,respectively.Results A decrease was observed in the color,hardness and thickness of scars in the irradiated ears compared with the unirradiated ears.The average thickness of scars,microvessel density and fibroblast density in scars were significantly lower in the treatment group than in the control group(2.137vs.3.089 am,t=5.72,P<0.01;38.333/mm2vs.68.056/mm2,t=4.93,P<0.01;166.940/mm2vs.355.000/mm2,t=13.36.P<0.01).Masson staining revealed a disorganized arrangement of collagen fibers in the control group but a sparse and regular alignment in the treatment group.Conclusion Long-pulsed 1064 nm Nd:YAG laser may promote the shrinkage and suppress the hyperplasia of scars.