Batista Jonas D, Zanetta-Barbosa Darceny, Cardoso Sérgio V, Dechichi Paula, Rocha Flaviana S, Pagnoncelli Rogério M
Department of Oral and Maxillofacial Surgery, School of Dentistry, Federal University of Uberlândia, Uberlândia, MG, 38400-902, Brazil.
Lasers Med Sci. 2014 Nov;29(6):1913-8. doi: 10.1007/s10103-014-1602-8. Epub 2014 Jun 10.
Radiotherapy (RDT) is commonly used for cancer treatment, but high doses of ionizing radiation can directly affect healthy tissues. Positive biological effects of low-level laser therapy (LLLT) on bone repair have been demonstrated; however, this effect on surgical defects of bone previously compromised by radiotherapy has not been evaluated. The aim of this study was to investigate the influence of LLLT (λ = 830 nm) in femur repair after ionizing radiation. Twenty Wistar rats were divided into four groups: control group (GC, n = 5) creation of bone defects (BDs) only; laser group (GL), with BD and LLLT (n = 5); radiotherapy group (GR), submitted to RDT and BD (n = 5); and radiotherapy and laser group (GRL), submitted to RDT, BD, and LLLT (n = 5). GL and GRL received punctual laser application (DE = 210 J/cm(2), P = 50 mW, t = 120 s, and beam diameter of 0.04 cm(2)) immediately after surgery, with 48-h interval during 7 days. Animals were euthanized at 7 days after surgery, and bone sections were evaluated morphometrically with conventional microscopy. Bone repair was only observed in nonirradiated bone, with significant improvement in GL in comparison to GC. GR and GRL did not present any bone neoformation. The result demonstrated a positive local biostimulative effect of LLLT in normal bone. However, LLLT was not able to revert the bone metabolic damage due to ionizing radiation.
放射治疗（RDT）常用于癌症治疗，但高剂量的电离辐射会直接影响健康组织。低强度激光疗法（LLLT）对骨修复的积极生物学效应已得到证实；然而，其对先前因放射治疗而受损的骨手术缺损的影响尚未得到评估。本研究的目的是调查LLLT（λ = 830 nm）对电离辐射后股骨修复的影响。将20只Wistar大鼠分为四组：对照组（GC，n = 5），仅制造骨缺损（BDs）；激光组（GL），有BD并接受LLLT（n = 5）；放射治疗组（GR），接受RDT并制造BD（n = 5）；放射治疗与激光组（GRL），接受RDT、BD并接受LLLT（n = 5）。GL和GRL在手术后立即接受定点激光照射（DE = 210 J/cm²，P = 50 mW，t = 120 s，光束直径为0.04 cm²），在7天内间隔48小时进行。在手术后7天对动物实施安乐死，并使用传统显微镜对骨切片进行形态计量学评估。仅在未受辐射的骨中观察到骨修复，与GC相比，GL有显著改善。GR和GRL未出现任何骨新形成。结果表明LLLT对正常骨有积极局部生物刺激作用。然而，LLLT无法逆转电离辐射导致的骨代谢损伤。
