Effects of low-level laser therapy (LLLT) on bone repair in rats: optical densitometry analysis (original) (raw)
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Laser therapy in bone repair in rats: analysis of bone optical density
Acta ortopedica brasileira, 2014
To investigate, by digital radiology, the bone regeneration process in rats submitted to femoral osteotomy and treated with low power laser therapy. Forty-five Wistar rats were subjected to transverse osteotomy of the right femur and divided randomly into three experimental groups (n = 15): animals not treated with laser therapy G (C), animals that received laser therapy with λ: 660nm G (660nm) and animals that received laser therapy with λ: 830nm G (830nm). Animals were sacrificed after 7, 14 and 21 days. The bone calluses were evaluated by digital X-ray at 65 kVp, 7mA and 0.032 s exposures. The values obtained were submitted to variance analysis (ANOVA) followed by the Tukey-Kramer test. The significance level adopted was 5%. The groups G (C), G (660nm), and G (830nm) at the 7(th) day showed a significant bone development, with p <0.0116; the groups G (C), G (660nm), and G (830nm) at the 14(th) day showed values of p <0.0001; at the 21(st) day,a higher degree of bone repair ...
Analysing the Effect of Low Level Laser Therapy on Bone Histomorphometry in Rats
Recent Research Advances in Biology Vol. 11, 2021
The aim of this study was to assess the histological effect of Low Level Laser Therapy (LLLT) (904 nm) on the repair of standardized bone defects on the femur of rats. Sixty male wistar rats were assigned into two equal groups. Group (A: laser group) and group (B: control group). A surgical fracture was done in middle third of femur of all rats. In group (A) a continuous wave 904 nm infrared laser was applied at dose 4 j/cm 2 at fracture site immediately post operative for 7 sessions, each session was 5 minutes. The animals were killed by over dose of general anesthesia on the 15th,30th and 45th days after surgery, The specimens were processed and stained with Hematoxylin-eosin (H/E), special stain Masion trichrome and analyzed by light microscopy. The descriptive analysis of histological imaging showed greater degree of new bone formation, osteoblastic surface and collagen fiber in the irradiated group when compared with the control group. Based on the obtained results, this study concluded that LLLT was efficient in promoting bone healing, and increasing new bone formation in the process of surgically fractured femur in animal study.
Histologic study of the effect of laser therapy on bone repair
The journal of contemporary dental practice, 2008
This study used histologic analysis and HE staining to evaluate laser biomodulation of bone repair in cavities made in the femurs of rats that underwent non-ablative laser irradiation. Eighteen male Wistar rats weighing 300 to 400 grams were randomly assigned to three groups of six animals each. A surgical defect site was produced with a trephine about 2 mm in diameter under abundant irrigation. In Group I the complete surgical protocol to produce a bone defect was followed but without laser radiation (control). In Group II a continuous wave 830 nm infrared laser was used at 10 J/cm2 and 50 mW at each point of the surgical site. In Group III a continuous wave 685 nm infrared laser at 10J/cm2 and 35 mW was used at each point of surgical site. The animals were irradiated at intervals of 48 hours beginning immediately after the preparation of the defect and were sacrificed on the 15th, 21st, and 30th days. Slides were studied by means of descriptive analysis. Greater degrees of new bon...
2002
Objective: The aim of this study was to evaluate morphometricly the amount of newly formed bone after GaAlAs laser irradiation of surgical wounds created in the femur of rats. Background Data: Low-level laser therapy (LLLT) has been used in several medical specialties because of its biomodulatory effects on different biological tissues. However, LLLT is still controversial because of contradictory reports. This is a direct result of the different methodologies used in these works. Materials and Methods: In this study, 40 Wistar rats were divided into four groups of 10 animals each: group A (12 sessions, 4.8 J/cm 2 per session, observation time of 28 days); group C (three sessions, 4.8 J/cm 2 per session, observation time of 7 days). Groups B and D acted as nonirradiated controls. The specimens were routinely processed to wax and cut at 6-mm thickness and stained with H&E. For computerized morphometry, Imagelab ® software was used. Results: Computerized morphometry showed a significant difference between the areas of mineralized bone in groups C and D ( p = 0.017). There was no difference between groups A and B (28 days; p = 0.383). Conclusion: It is concluded that, under this experimental condition, LLLT increased bone repair at early bone healing. 83
Lasers in Medical Science, 2011
The present study aimed to evaluate the effects of LLLT (660-and 808-nm wavelengths) on the process of repairing bone defects induced in the femurs of female rats submitted to ovariectomy. Bilateral ovariectomies were performed on 18 female Wistar rats, which were divided into control and irradiated groups after the digital analysis of bone density showed decreased bone mass and after standardized drilling of the femurs. The irradiated groups received 133 J/cm 2 of AsGaAl (660-nm) and InGaAlP (880-nm) laser radiation. The animals were euthanized on days 14 and 21 after the bone defects were established.
Effect of Low Level Laser Therapy on Bone Histomorphometry in Rats
Life Science Journal, 2011
Abstract: The aim of this study was to assess the histological effect of Low Level Laser Therapy (LLLT) (904 nm) on the repair of standardized bone defects on the femur of rats. Sixty male wistar rats were assigned into two equal groups. Group (A: laser group) and group (B: control ...
Low-level laser therapy on bone repair: is there any effect outside the irradiated field?
Lasers in Medical Science, 2015
The biological effects of local therapy with laser on bone repair have been well demonstrated; however, this possible effect on bone repair outside the irradiated field has not been evaluated. The aim of this study was to investigate the effect of low-level laser therapy (LLLT) (λ=830 nm) on repair of surgical bone defects outside the irradiated field, in rats. Sixty Wistar rats were submitted to osteotomy on the left femur and randomly separated into four groups (n=15): group I, control, bone defect only; group II, laser applied on the right femur (distant dose); group III, laser applied locally on the bone defect and also on the right femur (local and distant doses); and group IV, laser applied locally on the left femur (local dose). Laser groups received applications within a 48-h interval in one point per session of density energy (DE)= 210 J/cm 2 , P =50 mW, t = 120 s, and beam diameter of 0.028 cm. Five animals of each group were euthanized 7, 15, and 21 days after surgery. Histologic analysis in all groups showed new bone formation in the region of interest (ROI) at 7 days. After 15 days, bone remodeling with a decrease of bone neoformation in the marrow area was observed in all groups. After 21 days, advanced bone remodeling with new bone mostly located in the cortical area was observed. The histomorphometric analysis showed at 7 days a significant increase of bone formation in groups III and IV compared to groups I and II. At days 15 and 21, histomorphometric analysis showed no significant differences between them. Laser therapy presented a positive local biostimulative effect in the early stage of bone healing, but the LLLT effect was not observed a long distance from the evaluated area.
Low-Level Laser Therapy and Calcitonin in Bone Repair: Densitometric Analysis
The aim of this work was to evaluate the association of low-level laser therapy (LLLT, 830 nm) and calcitonin in bone repair considering that bone healing remains a challenge to health professionals. Calcitonin has antiosteoclastic action and LLLT is a treatment that uses low-level lasers or light-emitting diodes to alter cellular function. Both are used to improve bone healing. Densitometry is a clinical noninvasive valuable tool used to evaluate bone mineral density (BMD). Sixty male rats were submitted to bone defect with a trephine bur, randomly divided into four groups of 15 animals each: control (C); synthetic salmon calcitonin (Ca); LLLT (La); LLLT combined with calcitonin (LaCa). Animals from Ca and LaCa received 2 UI/Kg synthetic salmon calcitonin intramuscularly on alternate days after surgery. Animals from groups La and LaCa were treated with infrared LLLT (830 nm, 10 mW, 20 J/cm 2 , 6 s, contact mode). Five animals from each group were euthanized 7, 14, and 21 days after surgery and bone defects were analyzed by densitometry. Statistical analysis showed a significant difference in BMD values in LaCa group at 7 and 21 days (P = 0, 005). The results of the densitometric study showed that LLLT (830 nm) combined with calcitonin improved bone repair.
Experimental Gerontology, 2012
Background and objective: The goal of this study was to investigate the effects of low level laser therapy (LLLT) in osteoporotic rats by means of subjective histopathological analysis, deposition of collagen at the site of fracture, biomechanical properties and immunohistochemistry for COX-2, Cbfa-1 and VEGF. Material and methods: A total of 30 female Wistar rats (12 weeks-old, ±250 g) were submitted to ovariectomy (OVX). Eight weeks after the OVX, a tibial bone defect was created in all animals and they were randomly divided into 3 groups (n = 10): control bone defect group (CG): bone defects without any treatment; laser 60 J/cm 2 group (L60): animals irradiated with LLLT, at 60 J/cm 2 and laser 120 J/cm 2 group (L120): animals irradiated with LLLT, at 120 J/cm 2 . Results: In the laser treated groups, at both fluences, a higher amount of newly formed bone was evidenced as well as granulation tissue compared to control. Picrosirius analysis demonstrated that irradiated animals presented a higher deposition of collagen fibers and a better organization of these fibers when compared to other groups, mainly at 120 J/cm 2 . COX-2, Cbfa-1 or VEGF immunoreactivity was detected in a similar manner either 60 J/cm 2 or 120 J/cm 2 fluences. However, no differences were shown in the biomechanical analysis. Conclusion: Taken together, our results support the notion that LLLT improves bone repair in the tibia of osteoporotic rats as a result of stimulation of the newly formed bone, fibrovascularization and angiogenesis.
The effects of low-level laser irradiation on bone tissue in diabetic rats
Lasers in Medical Science, 2013
Diabetes mellitus (DM) leads to a decrease in bone mass and increase the risk of osteoporosis and in this context, many treatments have shown to accelerate bone metabolism. It seems that low-level laser therapy (LLLT) is able of stimulating osteoblast activity and produced increased biomechanical properties. However, its effects on bone in diabetic rats are not fully elucidated. The aim of this study was to evaluate the effects of LLLT on bone formation, immunoexpression of osteogenic factors, biomechanical properties and densitometric parameters in diabetic rats. Thirty male Wistar rats were randomly distributed into three experimental groups: control group, diabetic group, and laser-treated diabetic group. DM was induced by streptozotocin (STZ) and after 1 week laser treatment started. An 830-nm laser was used, performed for 18 sessions, during 6 weeks. At the end of the experiment, animals were euthanized and tibias and femurs were defleshed for analysis. Extensive resorptive areas as a result of osteoclasts activity were noticed in DG when compared to control. Laser-treated animals showed an increased cortical area. The immunohistochemical analysis revealed that LLLT produced an increased RUNX-2 expression compared to other groups. Similar RANK-L immunoexpression was observed for all experimental groups. In addition, laser irradiation produced a statistically increase in fracture force, bone mineral content (BMC) and bone mineral density compared to DG. The results of this study indicate that the STZ model was efficient in inducing DM 1 and producing a decrease in cortical diameter, biomechanical properties and in densitometric variables. In addition, it seems that LLLT stimulated bone metabolism, decreased resorptive areas, increased RUNX-2 expression, cortical area, fracture force, BMD, and BMC. Further studies should be developed to provide additional information concerning the mechanisms of action of laser therapy in diabetic bone in experimental and clinical trials.