The Therapeutic Effects of Long-term Photobiomodulation on Aging in Mice

ABSTRACT Background We have reported that photobiomodulation (PBM) therapy, a form of low dose Near Infrared Light (NIR) therapy, attenuates cardiovascular remodeling and extends the lifespan in a mouse model of accelerated cardiac aging. Here, we tested whether long-term PBM affects the aging process in normal male and female mice. Methods C57 mice, 18 months old, males (n=60) and females (n=60), were exposed to either NIR (850nm) at 25 mW/cm 2 for 2 min on weekdays (MT and FT groups) or nothing (M and F groups) for 12 months. Mice were subjected to bimonthly echocardiography examination, Gait analysis and Frailty assessments. Randomly selected mice were sacrificed bimonthly for fresh tissue samples. Results Age-associated deterioration in left ventricle, left atrium, aorta, brain blood perfusion, frailty, body temperature and gait that were observed in M and F groups during the 12-month observation period were significantly attenuated by PBM therapy in MT and FT groups. The medium lifespan was extended by 0.6 and 1.0 month in MT and FT groups, compared to M and F groups, respectively. There was a significantly lower prevalence of dermatitis, stroke and heart failure in MT and FT groups compared to M and F groups. Conclusion Our data showed for the first time that PBM therapy by whole body exposure, even started at old age in normal animals, significantly attenuated the age-associated deterioration in heart, vessels, brain, gait and frailty; reduced the prevalence of stroke and heart failure; and improved health span.