Effects of LED Light Irradiation on Ovariectomy-induced Bone Loss

• Main Authors: Hong yu-ya, 洪于雅
• Other Authors: Lin Chin-Liang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/54128791050350011648

碩士 === 國防醫學院 === 生物及解剖學研究所 === 97 === Osteoporosis has great socioeconomic significance. It has been recognized as a major public health problem and a major health threat. Postmenopausal osteoporosis is a common disease with a spectrum ranging from asymptomatic bone loss to disabling hip fracture. The National Institutes of Health consensus conference defined osteoporosis as a disease of increased skeletal fragility accompanied by low bone mineral density. According to previous studies, bone metabolism was affected with several of laser and light-emitting diodes (LED) treatments. However, the results with another light source (LED) on menopause of osteoporosis were unclear. The aim of this study is to investigate the effect of LED light irradiation on ovariectomy (OVX) - induced bone loss. Sprague-Dawley (SD) rats were divided into baseline group and 2 major groups (A&B) based on different irradiation starting time point. Every major group subdivided into four groups: sham-operated control (SC), OVX control (OC), sham-operated irradiated (SI), OVX irradiated (OI). The rats of A groups started to be irradiated with LED light (630nm) the next day after OVX, and sacrificed after 6 weeks. The rat of B groups started to be irradiated with LED light at 8th week, and sacrificed at 14th week. On 8th and 1st day before sacrifice, bone markers were administrated by intraperitoneal injection (IP). Tibias of rats were collected and analyzed for bone density, growth conditions, and mechanical strength and bone histomorphometry determination after sacrifice. In this study, OVX was efficient at inducing osteopenia in rats; OC and OI animals showed higher values of body weight and lower values of apparent bone density of spongy bone. According to the measurement of the tibia length, longitudinal growth rate, and growth plate thickness, LED light irradiation may enhance chondrocyte activities. LED light irradiation may increase osteoclast activities and numbers; but not on osteoblast after 6 weeks LED light irradiation. According to the bone volume change, rats of LED light irradiation groups did not have significant increase of bone volume when compared to irradiation control groups, but LED may have effect on osteoblasts of OVX groups at previous weeks after operation. There was no significant difference of mechanical strength testing among B groups. Bones of OVX animals have trends of lower stiffness than that of sham control. However the bone stiffness values of irradiation groups were slight higher than that of non-irradiation groups. In conclusions, LED light irradiation did not show significant effect on preventing OVX induced bone loss or treating the osteoporosis induced by OVX operation, but LED light irradiation may have positive effect on osteoclasts and chondrocyte activities; but has no influence on osteoblasts.