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/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 six and 12 sessions.
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/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 six and 12 sessions.
基金
FAPESP(Sao Paulo Research Foundation),Grant/Award Number:2011/50686-0
National Institute and Technology-Translational Medicine(INCT.TM)
CNPq(National Council for Scientific and Technological Development)
