Evaluation of the effects of LLLT on biomechanical properties of tibial diaphysis in two rat models of experimental osteoporosis by a three point bending test

Abstract

Osteoporosis (OP) is a disease which causes bone loss and fractures, leading to severe pain and deformity. This study has aimed to assess the effects of pulsed wave low-level laser therapy (PW LLLT) on cortical bone in two experimental models of OP in rats. There were four ovariectomized (OVX-d) groups and four dexamethasone-treated groups. The healthy group were considered for baseline evaluations. At 14 weeks following ovariectomy, the OVX-d rats were further subdivided into the following: control rats with OP, OVX-d rats that received alendronate (1 mg/kg), OVX-d rats treated with LLLT, and OVX-d rats treated with alendronate and LLLT. The remaining rats received dexamethasone for 5 weeks and were divided into four groups: control, alendronate-treated rats (1 mg/kg), laser-treated rats, and laser-treated rats with concomitant administration of alendronate. The rats received alendronate for 30 days. LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) was performed on the tibias three times per week for 8 weeks. After 8 weeks, tibias were extracted and submitted to a three-point bending test. PW LLLT did not increase the biomechanical parameters of osteoporotic bones compared to controls and healthy rats. PW LLLT associated with alendronate treatment significantly increased stress high load in OVX-d rats compared to the healthy group. PW LLLT at the current study parameters failed to cause beneficial biomechanical effects in the examined osteoporotic cortical bones. PW LLLT associated with alendronate treatment produced a more remarkable effect on bone strength in the ovariectomized induced OP rat model.

Effect of low‐level laser therapy and oxytocin on osteoporotic bone marrow‐derived mesenchymal stem cells

“…However, some recent studies show that LLLT alone is not effective in reversing the detrimental effects of OP in vivo …”

Beneficial Effects of a Flavonoid Fraction of Herba Epimedii on Bone Metabolism in Ovariectomized Rats

“…The most important marker of osteoporosis is the severe decrease in bone strength, which directly results in bone fractures [45]. The three-point bending test has been commonly used to evaluate bone strength [46], which has shown that bending ultimate load, modulus of elasticity, energy to failure, and stiffness are good indicators of the mechanical load of cortical bone [47]. In this study, the results of the three-point bending test of tibial diaphysis showed that the administration of HEFF at a higher dosage to OVX animals produced a significant increase in bone strength.…”

Low-level laser therapy with helium–neon laser improved viability of osteoporotic bone marrow-derived mesenchymal stem cells from ovariectomy-induced osteoporotic rats

“…28 In the current study, the authors used sham and OVX rats, which are most commonly used as experimental and control animal models for postmenopausal OP, 29 and the duration from bilateral ovariectomization to the extraction, isolation, and culture of BMMSCs was 3.5 months. 24,25 This model has also been approved by the Food and Drug Administration to be the primary model system for preclinical evaluation of agents used for the prevention and treatment of postmenopausal OP. 30 BMMSC from postmenopausal women with OP showed significant decreases in cell growth, proliferative response, and osteogenic differentiation.…”

“…The OVX rats were subjected to total ovariectomy. 24 OVX was carried out by two paravertebral skin incisions while the rats were under general anesthesia. The rats were anesthetized by intramuscular injections of 50 mg∕kg ketamine hydrochloride (Rotex Medica, Tritteu, Germany) together with 5 mg∕kg diazepam (Caspian, Rasht, Iran).…”