The effect of 830nm laser on femora of osteopenic rats

Abstract

Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and increasing in risk of fracture, mainly at the spine, the radius and the femora (Mitchell et al, 1998). Osteoporosis has been associated with an immense social-economic significance and is recognized as a major public health problem. In the USA alone, it is estimated that more than 20 million individuals are affected by this disease, with a total of 1,5 million fractures per annum (Mitchell et al, 1998). Many treatments have been developed with the aim of preventing bone loss and increasing bone mass, including estrogen replacement therapy, the use of bisphosphonate compounds and physical activity programs (Paz et al , 2001). Some attention has recently been paid to the effects of low level laser irradiation (LLLT) on bone tissue (Luger et al, 1997). Studies have shown that LLLT is able to stimulate bone cell proliferation and accelerate fracture consolidation. LLLT appears to promote increases in cell metabolism and ATP synthesis and to modulate the inflammatory process, therefore accelerating the bone consolidation process (Baxter, 1997; Pinheiro et al. 2001; Trelles e Mayago, 1987). In bone cell cultures, LLLT stimulates cell proliferation and increases osteoblastic activity and DNA synthesis (Luger et al, 1998; Tamura et al, 1998; Ozawa et al., 1998). Based on these data, we hypothesized that LLLT would be improve the bone mass of osteopenic bone tissue. The aim of the present study was to determine the effects of 830 nm laser, 100 W/cm2 ,applied in two different laser energy densities, 60 J/cm⠡nd 120 J/cm⠬ on the physical and biomechanical properties of femora in osteopenic rats submitted to ovariectomy .