Laser de baixa intensidade na reparação de tíbias de ratos submetidas a radiação ionizante
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Data
2011
Autores
Abramoff, Meire Maman Fracher [UNIFESP]
Orientadores
Pereira, Max Domingues [UNIFESP]
Tipo
Dissertação de mestrado
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Introdução: A radiacao ionizante (RI) desenvolve alteracoes estruturais que retardam e impedem a reparacao do tecido osseo. O LASER de baixa intensidade (LLLT) desencadeia o incremento celular qualitativo e quantitativo, acelerando o processo de reparacao no osso. OBJETIVO: Avaliar os efeitos do LLLT na reparacao de tibias de ratos submetidas a RI. METODO: Setenta e dois ratos Wistar-EPM-1, machos e saudaveis foram distribuidos nos seguintes grupos: Grupo I: Controle sham (18 tibias); Grupo II: LASER (18 tibias); Grupo III: RI (18 tibias); Grupo IV: RI e LASER (18 tibias). Os Grupos III e IV foram submetidos a RI com dose unica (30GY). Em cada tibia foi realizada uma perfuracao monocortical (ø=2,5mm), na porcao de diafise. Nos grupos III e IV, a operacao foi realizada apos 28 dias da RI. Nos grupos II e IV, foram realizadas tres aplicacoes de LLLT sobre a pele (AsGaAL, 100mW, 808nm, 20s, 3,57W/cm², 72J/cm², 2J), em dias alternados iniciando logo apos a operacao. A eutanasia ocorreu aos 7, 14 e 21 dias apos a cirurgia com seis amostras de osso de cada grupo. A histomorfometria foi realizada por analise digital da imagem e a celularidade foi analisada qualitativamente. RESULTADOS: Em todos os periodos: houve aumento significativo (p<0,006) de osso neoformado no Grupo IV, comparado ao Grupo III; nao houve diferenca significante entre o Grupo IV e o Grupo I; a radiacao ionizante reduziu a neoformacao ossea no Grupo III em comparacao ao Grupo I. CONCLUSAO: O LLLT aumentou a area ossea neoformada durante a fase inflamatoria abreviando a reparacao das tibias de ratos submetidas a RI
INTRODUCTION: Ionizing radiation (IR) develops structural changes that delay and restrain bone tissue repair. The Low-Level Laser therapy (LLLT) unchains a qualitative and quantitative cell growth, accelerating the bone repair process. OBJECTIVE: To evaluate the effects of LLLT on the repair of tibias from rats subjected to IR. METHOD: 72 male and healthy Wistar were divided into four groups: Group I: Sham Control (18 tibias), Group II: LASER (18 tibias), Group III: IR (18 tibias), Group IV: IR and LASER (18 tibias). Groups III and IV were submitted to IR with a single dose (30Gy). Monocortical perforation (diameter 2.5mm) was surgically performed in the portion of the tibial dyaphisis. In Groups III and IV, the surgery occurred 28 days after IR. In groups II and IV, post-surgery, three applications of LLLT were carried out (GaALAs, 100mW, 808nm, 20s, 3.57 W/cm², 72J/cm², 2J), on alternate days. Samples were collected after 7, 14 and 21 days. Histomorphometry was processed by digital image analysis and cellularity was qualitatively analyzed. RESULTS: In all periods, there was a significant increase (p <0.006) of new formed bone in Group IV when compared to Group III; no significant difference between Group I and Group IV was observed; the protocol of ionizing radiation reduced bone formation in Group III when compared to Group I. CONCLUSION: LLLT increased the newly formed bone area during the inflammatory phase, abbreviating the repair of rats tibias submitted to IR.
INTRODUCTION: Ionizing radiation (IR) develops structural changes that delay and restrain bone tissue repair. The Low-Level Laser therapy (LLLT) unchains a qualitative and quantitative cell growth, accelerating the bone repair process. OBJECTIVE: To evaluate the effects of LLLT on the repair of tibias from rats subjected to IR. METHOD: 72 male and healthy Wistar were divided into four groups: Group I: Sham Control (18 tibias), Group II: LASER (18 tibias), Group III: IR (18 tibias), Group IV: IR and LASER (18 tibias). Groups III and IV were submitted to IR with a single dose (30Gy). Monocortical perforation (diameter 2.5mm) was surgically performed in the portion of the tibial dyaphisis. In Groups III and IV, the surgery occurred 28 days after IR. In groups II and IV, post-surgery, three applications of LLLT were carried out (GaALAs, 100mW, 808nm, 20s, 3.57 W/cm², 72J/cm², 2J), on alternate days. Samples were collected after 7, 14 and 21 days. Histomorphometry was processed by digital image analysis and cellularity was qualitatively analyzed. RESULTS: In all periods, there was a significant increase (p <0.006) of new formed bone in Group IV when compared to Group III; no significant difference between Group I and Group IV was observed; the protocol of ionizing radiation reduced bone formation in Group III when compared to Group I. CONCLUSION: LLLT increased the newly formed bone area during the inflammatory phase, abbreviating the repair of rats tibias submitted to IR.
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Citação
ABRAMOFF, Meire Maman Fracher. Laser de baixa intensidade na reparação de tíbias de ratos submetidas a radiação ionizante. 2011. 172 f. Dissertação (Mestrado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2011.