Abstract: Catfish bone collagen peptide-calcium (F3-Ca) chelatate, which had been prepared in our laboratory, was evaluated for its effect on calcium transport and absorption using a Caco-2 cell model. Its effect on the alkaline phosphatase (ALP) activity of osteoblast hFoB1.19 and the expression of the key genes and proteins involved in osteoblast differentiation was also investigated. The results indicated that the chelate increased calcium transport in Caco-2 cells to 0.31 mg/mL, and promoted the mineralization of osteoblasts. The chelate at a concentration of 100 μg/mL increased the ALP activity of osteoblasts by 53.68% compared with the control group. Reverse transcription-polymerase chain reaction (RT-PCR) and protein immunoblot analysis showed that F3-Ca chelate increased the gene and protein expression levels of osteoprotegerin (OPG), osteocalcin (OCN) and runt-related transcription factor 2 (Runx2) in osteoblasts, reduced those of receptor activator for nuclear factor-κB ligand (RANKL), and increase the ratio of OPG/RANKL, thus activating the OPG/RANKL/receptor activator for nuclear factor-κb (RANK) signaling pathway, promoting the proliferation, differentiation and mineralization of osteoblasts, and ultimately resulting in enhanced calcium absorption and anti-osteoporosis activity. This study provides a scientific basis for the high-value utilization of catfish bone and the development of new calcium supplements.

Key words: catfish bone collagen peptide-calcium chelatate; calcium absorption; osteoblast differentiation; osteoporosis; calcium transport