Bone Abstracts

Breastfeeding leads to marked trabecular bone loss as a result of high osteoclast- and osteocyte-mediated bone resorption. It has long been postulated that adequate dietary calcium intake prevents maternal bone loss, nevertheless, whether calcium supplement alleviates maternal bone mechanical property need to be investigated. Herein, we hypothesized that calcium supplement from natural sources could alleviate bone loss and improve mechanical property in lactating rats. During lactation day 7–21, dams were daily gavaged with water (lactating control) or elemental calcium of 16 mg/kg body weight before breastfeeding. Tested calcium products were derived from fresh-water fish scale (FS), chicken-egg shell (ES) and calcium chloride (CaCl₂). After the end of experiment, tibiae and femora were collected for bone mineral density (BMD) measurement and mechanical property analysis. Calcium quantification was determined by inductively coupled plasma mass spectrometry (ICP-MS) and revealed that FS and ES powders contained 434.3±24.17 and 477.3±4.025 mg/g, respectively. X-ray diffraction revealed calcium crystal structure in FS and ES powders were mainly carbonate hydroxyapatite and calcium carbonate, respectively. From BMD measurement by micro-computed tomography, lactating rats given FS, ES and CaCl₂ before breastfeeding exhibited higher trabecular BMD at proximal metaphysis. The mechanical property test by three-point bending further revealed that lactating rats given FS showed higher ultimate load, yield load and stiffness than lactating control, whereas, only ultimate load was significantly increased in those given CaCl₂. There was no change in mechanical property of femora of lactating rats given ES. In conclusion, fresh-water fish scale is good natural source for calcium supplementation as it can alleviate bone loss and increase mechanical property of maternal skeletons.