Abstract: OBJECTIVE: To determine whether algal oligosaccharide affects the levels of parathyroid hormone 1-84(PTH1-84) and vascular endothelial growth factor(VEGF).METHODS: An osteoporosis rat model was established via bilateral ovariectomy. The model rats were fed algal oligosaccharides(molecular weights:600-1, 200 Da) for 4 months. Bone mineral density(BMD) was then measured. MG-63 human osteoblastic cells were treated with algal oligosaccharides. The expression of PTH1-84 and VEGF was then examined. Oligosaccharide-treated cells were transfected with PTH1-84 short hairpin RNA(sh RNA), VEGF sh RNA, and PTH1-84-VEGF small interfering RNA(si RNA). The growth rates were then compared between transfected and non-transfected cells.RESULTS: Algal oligosaccharides increased the BMD of the osteoporosis rat model compared with untreated controls(P < 0.05). When MG-63 cells were treated with algal oligosaccharides, the growth rate increased by 25% compared with the control group at day 3(P < 0.05). In addition, the expression of PTH84 and VEGF was enhanced. Con-versely, when the cells were transfected with PTH84 sh RNA, VEGF sh RNA, or PTH1-84-VEGF si RNA, the growth rate was decreased by 17%, 35% and 70%, respectively, compared with controls at day 3(P < 0.05).CONCLUSION: Algal oligosaccharides ameliorate osteoporosis via up-regulation of PTH1-84 and VEGF. Algal oligosaccharides should be developed as a potential drug for osteoporosis treatment.

Key words: Osteoporosis, Bone density, Sargassum, Oligosaccharides, Parathyroid hormone, Vascular endothelial growth factor A, MG-63 human osteoblastic cells