Alterações estruturais do colágeno da placa de crescimento irradiado por laser de baixa intensidade: uma investiação por microscopia de força atômica

Th is study investigated through the microscopy of the atomic force the systemic and local eff ect of the laser radiation on the bone growth plate. 30-day-old Wistar rats, randomly divided, were used in this experiment: Group GC (n = 5), not irradiated by laser; Group G5J (n = 10), irradiated by laser, (ö = 780 nm, mean output power = 20 mW, fl uency rate = 5 J/cm2, time = 10 seconds) and fi nally, the Group G60J (n = 10) also irradiated by low intensity laser (ö=780 nm, mean output power = 20 mW, fl uency rate = 60 J/cm2, Time = 120 seconds). From these groups, we evaluated the systemic eff ect on the contra lateral plate and we named them as G5JS (n = 10) – the evaluation of the contra lateral growth plate to the irradiated one of the Group G5J and the Group G60JS (n = 10) – the evaluation of the contra lateral growth plate to the irradiated one of the Group G60J. Th e treatment consisted of six laser applications through the punctual technique on the back right paw over the antero-medium region of the growth plate near the tibia, with a 48-hour interval between the irradiations. We observed an increase on the thickness of the collagen sheaves, changing of orientation sense and organization of these sheaves, mainly through the local eff ect. Laser can cause structural changes on the collagen sheaves, but our results are not enough to claim that the bone increase can be aff ected. Key-words: laser, AFM, growth plate. Recebido 5 de julho de 2006; aceito 15 de outubro de 2006. Endereço para correspondência: Nivaldo Antonio Parizotto, Laboratório de Eletrotermofototerapia, Departamento de Fisioterapia, Universidade Federal de São Carlos, Via Washington Luís, km 235, CP 676, 13565-905 São Carlos SP, Tel: (16) 3351 8630 E-mail: parizoto@power.ufscar.br Fisioterpia_v7n5.indb 367 10/11/2006 17:53:13 Fisioterapia Brasil Volume 7 Número 5 setembro/outubro de 2006 368