Date of Award

August 2014

Degree Type


Degree Name

Doctor of Philosophy



First Advisor

Karen Morin

Second Advisor

Mary Pat Kunert

Committee Members

Christine Kovach, Kim Litwack, Carol Porth, Ruth Globus, Jeri-Annette Lyons


Cell Line, Cells, Cultured, Infrared Rays/therapeutic Use, Laser Therapy, Low-level, Osteoclasts, Postmenopausal Osteoporosis


After critically examining the literature to gain a robust understanding for the pathogenesis of bone loss, specifically osteoporosis, the development of a possible new intervention to prevent or treat osteoporosis was explored. The purpose of this dissertation was to pilot test a new protocol designed to answer the broad research question: Does Near-Infrared Light Emitting Diode (NIR-LED) treatment affect Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL) induced osteoclastogenesis in a cell culture model?

Osteoporosis is defined as a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures, especially of the hip, spine, and wrist. Specifically, osteoporosis has been shown to increase the risk for fracture resulting from a fall. The World Health Organization reported in 2003 that osteoporosis-induced fractures burden society due to the great health care costs for treatment and rehabilitation. Experts have estimated that, between 2005-2025, the incidence and economic burden to treat osteoporotic related fractures will increase 50% annually (Burge et al., 2007). The development of additional interventions meant to slow the progression of osteoporosis may contribute to decreasing this burden. Near-Infrared Light Emitting Diode (NIR-LED) photobiomodulation has been found to be effective in improving wound healing, bone regeneration, mitochondrial function, and attenuating cellular oxidative stress. Little is known regarding the use of NIR-LED and the formation of osteoclasts, which break down bone.

This pilot study included two experiments using the WARPTM 75 light source. RAW264.7 cells were cultured for 24 hours and induced to differentiate into osteoclasts, using the cytokine Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL). Cultures were divided into groups according to RANKL dose (0, 2.5, 10, 25, 50 ng/ml) and different energy densities (2.25, 4.5, 45 J/cm²), treated with light either once or on four consecutive days using the WARPTM 75 (Quantum Devices, Barneveld, WI). Osteoclast-like cells were stained for Tartrate-Resistant Acid Phosphatase (TRAP). Multinucleated, TRAP+ cells were scored as osteoclasts, counted manually by microcopy. Results were expressed as means and standard deviations, and groups were compared by one-way ANOVA with posthoc Tukey. RANKL-induced osteoclast formation by RAW264.7 cells occurred as expected in all experiments. Light-treatment alone had no observable effect. A single light-treatment at 4.5 J/cm2 with RANKL added (10 - 50ng/ml) suggested a biostimulatory effect upon osteoclastogenesis compared to controls, as multiple light-treatments compared to single light-treatment were less stimulatory in the energy density 4.5 J/cm2 and RANKL dose 25ng/ml group. In conclusion, effects of NIR-LED treatment on osteoclastogenesis are RANKL dose and light-intensity specific. NIR-LED light-treatment affects RANKL-induced osteoclast formation suggestive of a biostimulatory effect, and multiple light treatments compared to single light treatment may biostimulate osteoclastogenesis less.

These experiments provide the foundation to further investigate possible NIR-LED effects upon bone formation and include alternative bone formation quantification utilizing alternative cellular assays. Contributing to this body of knowledge provides insight for nurses' application of new therapies to prevent and treat bone loss.