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

Abstract

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.

Improved healing of critical-size femoral defect in osteoporosis rat models using 3D elastin/polycaprolactone/nHA scaffold in combination with mesenchymal stem cells

“…Each year, thousands of people in the world suffer from various kinds of bone disease and defects such as trauma or tumors. On the other hand, many people die due to insufficient perfect bone substitute [ 4 ]. Besides, there is an extensive history of using auto graft or allograft bones for treatment of bone defects.…”

“…Osteoporosis is a global age-related disorder described by an imbalance between osteoblasts-associated bone formation and osteoclasts-associated bone resorption, usually as a result of postmenopausal deficiency of estrogen [ 4 , 5 ]. This condition leads to trabecular and cortical bone mass reduction that subsequently causes several complications such as skeletal instability and fractures [ 5 , 6 ].…”

Bone Regeneration and Oxidative Stress: An Updated Overview

“…Osteoporosis, which can be considered a discrepancy between osteoclasts-related bone resorption and osteoblasts-related bone development, can be caused by an estrogen deficiency [ 56 , 57 ]. The condition results in the mass reduction of cortical and trabecular bone, causing skeletal weakness and fractures.…”

Efeito da fotobiomodulação associada à membrana texturizada poli(vinilideno-trifluoretileno)/titanato de bário no reparo de defeitos ósseos em calvárias de ratas ovariectomizadas

“…A literatura tem demonstrado os benefícios da fotobiomodulação na reparação óssea (SIESSERE et al, 2011;ROSA et al, 2012;PINHEIRO et al, 2014), porém o assunto é bastante controverso tendo em vista as variações existentes nos protocolos de irradiação. O protocolo utilizado neste estudo (diodo AsGaAL; comprimento de onda de 780 nminfravermelho; 40 mW de potência e densidade de energia de 30J/cm 2 ) foi baseado em estudos anteriores que demonstraram sua efetividade na neoformação óssea em animais ovariectomizados (SCALIZE et al, 2015), acarretando inclusive num aumento do número de osteócitos (SCALIZE et al, 2019).…”

“…Seguindo o mesmo protocolo utilizado para os animais sham (pesagem, anestesia, tricotomia, antissepsia e proteção dos olhos) 35 animais foram ovariectomizados (Ovx) bilateralmente. Após incisão na pele do animal, a musculatura foi afastada e os ovários foram expostos e excisionados (KALU, 1991;SCALIZE et al, 2015;SCALIZE et al, 2016;SCALIZE et al, 2019).…”