The influence of LLLT applied on applied on calvarial defect in rats under effect of cigarette smoke

Abstract

Objective: Considering the global public health problem of smoking, which can negatively influence bone tissue repair, the aim of this study is to analyze the influence of photobiomodulation therapy (PBM) on calvaria defects created surgically in specimens under the effect of cigarette smoke and analyzed with use of histomorphometric and immunohistochemistry techniques.Methodology: Calvaria defects 4.1 mm in diameter were surgically created in the calvaria of 90-day-old rats (n=60) that were randomly divided into 4 experimental groups containing 15 animals each: control group (C), smoking group (S), laser group (L), and smoke associated with laser group (S+L).The animals were subjected to surgery for calvaria defects and underwent PBM, being evaluated at 21, 45, and 60 days post-surgery. The specimens were then processed for histomorphometric and immunohistochemistry analyses. The area of bone neoformation (ABN), percentage of bone neoformation (PBNF), and the remaining distance between the edges of the defects (D) were analyzed histometrically. Quantitative analysis of the TRAP immunolabeled cells was also performed. The data were subjected to analysis of variance (ANOVA) in conjunction with Tukey's test to verify the statistical differences between groups (p<0.05). Results: The smoking group showed less ABN compared to the other experimental groups in all periods, and it also showed more D at 21 days compared to the remaining groups and at 45 days compared to the laser group. The smoking group showed a lower PNBF compared to the laser group in all experimental periods and compared to smoking combined with LLLT group at 21 days. Conclusions:PBM acted on bone biomodulation, thus stimulating new bone formation and compensating for the negative factor of smoking, which can be used as a supportive therapy during bone repair processes.

Effect of Photobiomodulation Therapy Associated With Biphasic Phosphate Calcium on Bone Repair: A Histomorphometric Study in Rats

“…The remaining distance between corticals formed from the neoformed bone on the edges in the upper and lower regions was denoted as DBSC-NB and DBIC-NB respectively. 28,31 These measures provided us with complementary data regarding the dimension of defect closure.…”

“…The positive action of PBM with respect to this parameter has been previously reported. 28,29,31 PBM is able to create environmental conditions that accelerate bone healing by stimulating the proliferation and differentiation of osteoblasts in vivo and in vitro, which would consequently lead to an increase in bone formation. 41 Therefore, PBM can be considered a non-invasive biostimulation method based on this study, and it is promising for stimulating osteogenesis.…”

“…Also, there are studies with longer initial periods for PBM analysis in the literature. 31,42 Moreover, the presence of complementary analyses, such as immunohistochemistry, could open discussions about the action of PBM at the cellular level, which is not possible to be done only with histomorphometry, and the addition of micro-computed microtomography (micro-CT) would bring us the dimension of closing the defect in an assertive and concrete way. Therefore, more pre-clinical studies are necessary to determine specific protocols of the association between BCP and PBM.…”