Effects of alpha-Lipoic Acid on Bone Metabolism in Rats with Low Bone Mass / 대한내분비학회지

ABSTRACT

BACKGROUND: Growing evidence has shown a biochemical link between increased oxidative stress and reduced bone density. In our previous study, alpha-lipoic acid (alpha-LA), a thiol antioxidant, suppressed both osteoclastogenesis and bone resorption, and also prevented TNF-alpha-induced apoptosis of osteoblast lineages. The effects of alpha-LA were investigated on bone metabolism in rats with a low bone mass. METHODS: An ovariectomy (OVX) or Talc injection (inflammation-mediated osteopenia, IMO) was performed in 12 week old female Sprague-Dawley rats. Diets containing either 0.3%, 0.5% or 1.0% alpha-LA were administered to the OVX rats for 16 weeks, and to the IMO rats for 21 days. The bone mineral densities (BMD) of the anterior-posterior lumbar spine and total femur were measured using dual-energy X-ray absorptiometry (Hologic QDR 4500-A), with small animal software. The plasma bone specific alkaline phosphatase activity (BSAP) and urinary free deoxypyridinoline concentration (DPD) were determined using enzyme immunoassay methods. RESULTS: The body weights were significantly decreased in the OVX rats on the diets containing 0.3 and 0.5% alpha-LA than in the OVX control. No significant differences in the BMD at either site were noted between rats administered the diets with or without alpha-LA. However, the administration of various doses of alpha-LA noticeably decreased the level of urinary DPD in both the OVX and IMO rats. High doses of alpha-LA (0.5% and/or 1.0%) also decreased the levels of plasma BSAP in both models. CONCLUSION: Although no increase in BMD was demonstrated by the administration of alpha-LA, these results suggest that alpha-LA suppresses the rates of bone turnover in rats with a low bone mass