Anabolic Effect of β-Cryptoxanthin on Bone Components in the Femoral Tissues of Aged Rats in Vivo and in Vitro

Abstract

The effect of β-cryptoxanthin on bone components in the femoral tissues of aged rats was investigated. β-Cryptoxanthin was isolated from Satsuma mandarin (Citrus unshiu MARC.). β-Cryptoxanthin (5, 10, or 20 μg/100 g body weight) was orally administered once daily for 7 days to aged (50 week old) female rats. The administration of β-cryptoxanthin (10 or 20 μg/100 g body weight) caused a significant increase in calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the femoral-diaphyseal and -metaphyseal tissues. Femoral-diaphyseal calcium content and alkaline phosphatase activity were significantly increased by the dose of 5 μg/100 g body weight. A significant increase in metaphyseal alkaline phosphatase activity was also seen with the dose of 5 μg β-cryptoxanthin/100 g body weight. Moreover, bone tissues were cultured for 48 hr in serum-free Dulbecco's modified Eagle's medium containing either vehicle or β-cryptoxanthin (10^-7 or 10^-6 M). The presence of β-cryptoxanthin (10^-7 or 10^-6 M) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues obtained from aged (50 week old) female rats. These increases were completely abolished in the presence of cycloheximide (10^-6 M), an inhibitor of protein synthesis. This study demonstrated that β-cryptoxanthin has an anabolic effect on bone components in aged female rats in vivo and in vitro.