Potassium titanyl phosphate laser-induced inflammatory response and extracellular matrix turnover in rabbit vocal fold scar

Purpose The objectives of this study were to observe the regulating effect of KTP laser and Nd:YAG laser in the repair of vocal fold scars. Methods All rabbits were injured in the muscular layer with a sharp instrument, and then the vocal folds were treated with a KTP laser and a Nd:YAG laser at a power of 2, 4, 6 and 8 W 1 month after the injury. One month after treatment, the rabbits were killed and the throats were removed to detect changes in histology and gene expression of the vocal fold scar after laser therapy. Results The best efficacy of all KTP laser treatment groups was the KTP laser 6 W group. Regarding the detection of gene expression, in the KTP laser 6 W and Nd:YAG laser 6 W groups, col-3A1 was decreased compared to the scar group ( P < 0.05), and col-1A1 was decreased only in the KTP laser 6 W group ( P < 0.05). TGF-β1 levels in the two groups were lower than in the scar group. There were also significant differences in the levels of IL-1β, COX-2 and TNF-α in the two laser groups compared with the scar group ( P < 0.05). Conclusion KTP laser and Nd:YAG laser treatments for vocal fold scars have particular therapeutic effects. The KTP laser may be better than the Nd:YAG laser for the regulation of vocal fold scars. Level of evidence NA.