Chitooligosaccharides prevent osteopenia by promoting bone formation and suppressing bone resorption in ovariectomised rats: possible involvement of COX-2

Chitooligosaccharides (CHOS) added in diet have been found as potent calcium fortifiers in conditions of Ca(2+) deficiency such as osteoporosis. In this study, we found that pharmaceutical intervention using CHOS prevented ovariectomy (OVX)-induced bone mineral density loss and the deterioration of trabecular microarchitecture in a dose-dependent manner (p < 0.05 or 0.01). CHOS (125, 250 mg/kg) suppressed the serum levels of bone resorption biomarkers CTx and TRACP5b induced by OVX (p < 0.05), but increased the levels of osteogenic markers ALP and OC by 11.3-11.6% and 10.7-15.2% of OVX group (p < 0.05), suggesting the exact pharmacological action of CHOS in the control of osteoporosis which may be the result of both promoting bone formation and suppressing bone resorption. Bone turnover-modulating effects of CHOS appear related to their anti-inflammatory capacity to down-regulate mRNA and protein expression of COX-2 (17.2-32.2% and 16.4-21.9% of OVX group, p < 0.05 or 0.01), a key mediator linking between inflammation and osteoporosis.