Oral Administration in Combination with Zinc Enhances .BETA.-Cryptoxanthin-Induced Anabolic Effects on Bone Components in the Femoral Tissues of Rats in Vivo

Abstract

The effects of combined beta-cryptoxanthin and zinc on bone components in the femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues of rats in vivo were investigated. Rats were orally administered either vehicle, beta-cryptoxanthin (5 or 10 microg/100 g body weight), zinc sulfate (0.1 or 0.5 mg Zn/100 g), or their combination once a day for 7 d. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal tissues was not significantly altered by the administration of beta-cryptoxanthin (5 microg/100 g) or zinc (0.1 or 0.5 mg/100 g). Combined administration of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g) caused a synergistic increase in calcium content, alkaline phosphatase activity, and DNA content in the diaphyseal tissues. The effect of beta-cryptoxanthin (5 or 10 microg/100 g) in increasing calcium and DNA contents in the metaphyseal tissues was significantly enhanced by the combined administration of zinc (0.1 or 0.5 mg/100 g), but did not have a significant effect on the metaphyseal components. The metaphyseal alkaline phosphatase activity was markedly increased by the combination of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g). This study demonstrates that the oral administration of the combination of zinc at lower doses synergistically enhances beta-cryptoxanthin-induced anabolic effects on bone components in the femoral tissues of rats in vivo.