Effect of low-level laser therapy on irradiated parotid glands--study in mice.
The objective of this study was to evaluate the effect of low-level laser therapy (LLLT) on radiotherapy-induced morphological changes and caspase-3 immunodetection in parotids of mice. Forty-one Swiss mice were divided into control, radiotherapy, 2- and 4-J laser groups. The experimental groups were exposed to ionizing radiation in a single session of 10 Gy. In the laser groups, a GaAlAs laser (830 nm, 100 mW, 0.028  cm2, 3.57  W/cm2) was used on the region corresponding to the parotid glands, with 2-J energy (20 s, 71  J/cm2) or 4 J (40 s, 135  J/cm2) per point. LLLT was performed immediately before and 24 h after radiotherapy. One point was applied in each parotid gland. The animals were euthanized 48 h or 7 days after radiotherapy and parotid glands were dissected for morphological analysis and immunodetection of caspase-3. There was no significant difference between groups in the immunodetection of caspase-3, but the laser groups had a lower percentage compared to the radiotherapy group. LLLT promoted the preservation of acinar structure, reduced the occurrence of vacuolation, and stimulated parotid gland vascularization. Of the two LLLT protocols, the one using 4 J of energy showed better results.
Pontifical Catholic University of Rio Grande do Sul-PUCRS, Oral Medicine Division, São Lucas Hospital, Avenue Ipiranga, 6690, Room 231, CEP: 90610-000, Porto Alegre, RS, Brazil.
Monique Dossena
MD
Acauan
Federal University of Pelotas-UFPEL, Oral Pathology Division, Rua Gonçalves Chaves 457, CEP: 96015-560, Pelotas, RS, Brazil.
Ana Paula Neutziling
AP
Gomes
Pontifical Catholic University of Rio Grande do Sul-PUCRS, Radiotherapy Division, São Lucas Hospital, Brazil.
Aroldo
A
Braga-Filho
Pontifical Catholic University of Rio Grande do Sul-PUCRS, Oral Medicine Division, São Lucas Hospital, Avenue Ipiranga, 6690, Room 231, CEP: 90610-000, Porto Alegre, RS, Brazil.
Maria Antonia Zancanaro
MA
de Figueiredo
Pontifical Catholic University of Rio Grande do Sul-PUCRS, Oral Medicine Division, São Lucas Hospital, Avenue Ipiranga, 6690, Room 231, CEP: 90610-000, Porto Alegre, RS, Brazil.
Karen
K
Cherubini
Pontifical Catholic University of Rio Grande do Sul-PUCRS, Oral Medicine Division, São Lucas Hospital, Avenue Ipiranga, 6690, Room 231, CEP: 90610-000, Porto Alegre, RS, Brazil.
Fernanda Gonçalves
FG
Salum
D000818:Animals; D053148:Caspase 3 / Q000276:immunology; D004307:Dose-Response Relationship, Radiation; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D051379:Mice; D010306:Parotid Gland / Q000276:immunology* / Q000473:pathology* / Q000528:radiation effects; D011829:Radiation Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D016896:Treatment Outcome
D053148:Caspase 3