Improvement of bone repair in diabetic rats subjected to ƛ780 nm low-level laser therapy

Abstract

Brazil. Design of the study, histological examinations, manuscript writing, supervised all phases of the study. ABSTRACT PURPOSE:To investigate the effect of low-level laser therapy on bone healing in diabetic rats. METHODS:Bone cavities (19 mm diameter) were performed in the femur of 72 alloxan-induced diabetic rats, which were assigned into four groups: CTR (non-diabetic control), DBT (diabetic) CTRL (non-diabetic irradiated) and DBTL (diabetic irradiated). Low-level laser therapy was performed every 48h for seven days. Animals were euthanized at seven, 18 and 30 days. Alkaline phosphatase serum levels and bone repair were analyzed. RESULTS:Low-level laser therapy significantly increased alkaline phosphatase in at seven and 18 days (p<0.001), and improved bone healing at seven (p<0.01), 18 (p<0.05) and 30 (p<0.01) in diabetic animals. In addition, bone healing in irradiated diabetic group was statistically similar to control group at 30 days (p>0.05). CONCLUSION:Low-level laser therapy increased the serum levels of alkaline phosphatase and improved bone healing in alloxaninduced diabetic rats.

Effects of Different Protocols of Low-Level Laser Therapy on Collagen Deposition in Wound Healing

“…Low-level laser therapy provided a significant decrease in the severity of the inflammatory response in the late phases of wound healing independent of the protocol used. Supporting our findings, similar results have also been reported in the literature (15)(16)(17).…”

“…Paradoxically, Pereira et al (19) have observed that LLLT in the red spectrum promotes a significant increase in mast cell degranulation in the first 24 h after tissue aggression, generating a transient amplification of the acute inflammatory response, followed by a substantial reduction in neutrophil content after 36 h. These data seem to suggest that LLLT modulates the inflammatory response in order to accelerate the acute phase and thus culminate in the anticipation of process chronification. Although the precise mechanisms underlying the modulatory effects of LLLT on the inflammatory response were not investigated in the current paper, it is possible to suggest that it might be related to the inhibitory effect of laser energy on the release of pro-inflammatory chemical mediators, such as TNF-α, IL-1β and IL-6, as previously described (15). However, further investigations are still necessary to attest this hypothesis.…”

“…Thus, LLLT would be able to improve scar repair by direct stimulation of fibroblastic metabolism, promoting an enhancement of the in intracellular levels of adenosine triphosphate and consequently increased protein synthesis, particularly collagen (16). In addition, LLLT promotes important changes in the chemical mediators directly involved in repair, such as reduction of cyclooxygenase-2 (COX-2) expression and consequently the severity of the inflammatory response and increased expression of VEGF, a crucial growth factor for formation of granulation tissue (15,21).…”

“…However, many other controversial data have been reported in the literature on the laser photobiomodulator effect on scar repair, including reduction in collagen synthesis (12)(13)(14). This apparent paradox is most likely a result of the variety of parameters used in the experiments, such as energy density and intensity, irradiation time and irradiation mode, for example (15).…”

Apoptosis in Bone Defect of Diabetic Rats Treated with Low Intensity Laser: Radiological and Immunohistochemical Approach

“…In our study, we found that the induction with the alloxan was effective in the development of experimental diabetes due to irreversible damage in beta cell, as found by Nascimento et al (2015), who used this drug and obtained similar results, being it an excellent experimental model.…”