RESUMO
UNLABELLED: Heat shock proteins (HSPs) are conservative protective proteins responsible for protein integrity during transcription in the cell under stress. Hsp47 is one of the most important chaperonins for collagen synthesis and release, and is up-regulated during wound repair. The aim of this study was to verify whether defocused high-energy diode laser (DDL) causes sufficient increase in local temperature to cause Hsp47 up-regulation during repair of oral ulcers. Chemically-induced ulcers in the rat tongue, and non-ulcerated tongue mucosa were irradiated using a high energy diode laser (non-contact - 4mm from surface, 500 mW, 10 Hz for 40s, energy density 80 J/cm(2), fixed ulcer area of 0.25 cm(2)). Afterwards the specimens were submitted to immunohistochemical test for Hsp47. Temperature oscillation during DDL irradiation was also measured using a thermographic camera. Irradiated specimens exhibited transient mild increase in local temperature and significant up-regulation of Hsp47 in the mucosa from the superficial region (p=0.035) to 1.7 mm deep (p=0.049). In the deepest region of the mucosa Hsp47 was up-regulated only in ulcerated specimens mainly at 24h (p=0.049) and 72 h (p=0.029) after ulcer induction. CONCLUSION: DDL increases local temperature and Hsp47 expression, which may contribute to wound repair by improvement collagen synthesis and release.