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

[摘要] 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 three, six or 12 sessions of LLLT at 0, 20 or 30 J/cm2 , 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 (Nvost), total osteocyte number (Ntoost), trabecular surface density (Svt ), and trabecular surface area (Sat ). Results: Data obtained showed that Ntoost, Svt , and Sat in group G2 rats were significantly different from G1 (0 J/cm2 ) (P < 0.05). Compared to group G4, G5 presented higher values for the parameters Svt and Sat , and G6 presented significantly higher values for almost all the analyzed parameters (Nvost, Ntoost, Svt , and Sat ) (P < 0.05). Compared to group G7, G8 showed a higher value only for the parameter Sat , and G9 showed significantly higher values for parameters Nvost, Ntoost, Svt , and Sat . 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/cm2 given for six and 12 sessions.

[学科分类] 机械工程学

[关键词] bone;low‐level laser therapy;osteocytes;osteoporosis