Low-level laser therapy enhances the number of osteocytes in calvaria bone defects of ovariectomized rats.

Background: Osteoporosis can make bone repair difficult. Low-level laser therapy (LLLT) has been shown to be a promising tool for bone neoformation. This study aimed to analyze the effect of LLLT on calvaria bone defects of ovariectomized rats using stereology.
Methods: Fifty-four Wistar rats were subjected to bilateral ovariectomy, and bone defects were created in calvaria after 150 days. The animals were divided into nine groups (n =  6 per group), and 24 hours after the bone defects were created they received 3, 6 or 12 sessions of LLLT at 0, 20 or 30 J/cm ² , using a 780-nm low-intensity GaAlAs laser. One-way ANOVA followed by Tukey's post hoc test was used for data processing. A difference of P  < 0.05 was considered statistically significant. The parameters evaluated were osteocyte density ( Nv _ost ), total osteocyte number ( Nto _ost ), trabecular surface density ( Sv _t ), and trabecular surface area ( Sa _t ).
Results: Data obtained showed that Nto _ost , Sv _t , and Sa _t in group G2 rats were significantly different from G1 (0 J/cm ² ) ( P  < 0.05). Compared to group G4, G5 presented higher values for the parameters Sv _t and Sa _t , and G6 presented significantly higher values for almost all the analyzed parameters ( Nv _ost , Nto _ost , Sv _t , and Sa _t ) ( P  < 0.05). Compared to group G7, G8 showed a higher value only for the parameter Sa _t , and G9 showed significantly higher values for parameters Nv _ost , Nto _ost , Sv _t , and Sa _t .
Conclusion: We conclude that LLLT stimulated bone neoformation and contributed to an increase in the total number of osteocytes, especially with a laser energy density of 30 J/cm ² given for 6 and 12 sessions.
Competing Interests: None.