Preventive effect of marine alga Sargassum horneri extract on bone loss in streptozotocin-diabetic rats in vivo

The effect of Sargassum horneri (S. horneri) extract on bone components in the femoral-diaphyseal and -metaphyseal tissues of streptozotocin (STZ)-diabetic rats was investigated. Rats received a single subcutaneous administration of STZ (6.0 mg/100 g body weight), and then the animals were orally administered water-solubilized extract (10 mg/ 100 g body weight) of, S. horneri once daily for 14 or 21 days. The administration of STZ caused a significant decrease in body weight and a significant increase in serum glucose, triglyceride, and calcium levels, indicating a diabetic state. These alterations were significantly prevented by the administration of S. horneri extract for 14 or 21 days. The administration of S. horneri extract to normal rats for 14 or 21 days did not have a significant effect on body weight or serum glucose, triglyceride, and calcium levels. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues were significantly decreased in STZ-diabetic rats. These decreases were significantly prevented by the administration of S. horneri extract for 14 or 21 days. The administration of S. horneri extract to normal rats for 14 or 21 days caused a significant increase in calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues. Femoral-diaphyseal and -metaphyseal tissues obtained at 14 days after STZ administration were cultured for 48 hr in a medium containing either vehicle or S. horneri extract (10, 25, or 50 mug/ml of medium) in vitro. Calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues obtained from STZ-diabetic rats was significantly increased in the presence of S. horneri extract (10, 25, or 50 mug/ml). The present results demonstrate that the intake of S. horneri extract has a preventive effect on bone loss in STZ-diabetic rats.