To Establish an Animal Model to Evaluate the Effect of a Nutrient or Nutraceutical on Bone Growth

• Main Authors: Hsiu-Ching Cheng, 鄭秀卿
• Other Authors: Jimmy Tsai
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/m5h5r7

碩士 === 中原大學 === 化學研究所 === 93 === The main goal of this study was to establish a simple and reliable method to evaluate the effects of a health food on growing bones. The study tried to use parameters of the effect of various levels of calcium (Ca) and soy extract (S) combinations on the activities of osteoblasts (OB) and osteoclasts (OC) in growing rats. Fifty-six 3 weeks old female Wistar rats were housed individually in stainless steel cages. Forty-eight of them were assigned into 6 dietary groups randomly, 8 each, and fed 1/4Ca, 1/2Ca, Ca (AIN-93G recommendation), or with 0.15% S (contained 0.027% isoflavone) in the diets (1/4CaS, 1/2CaS, CaS). Eight of them were ovariectomized and fed CaS diet (CaSOx). All rats were fed ad libitum for 12 weeks. After feeding the experimental diets, two bone formation markers, serum Bone-specific Alkaline Phosphatase (BAP) and C-terminal of type-I Collagen Propeptide (CICP), and 2 bone resorption markers, serum Pyridinoline (Pyd) and cross-linked N-telopeptides of type I collagen (NTx) were determined. Bone sections by histomorphometry were also employed to determine the numbers of OB and/or OC, trabecular Mineral Apposition Rates (MAR), the thicknesses of growth plate, and bone volume. Besides the above parameters, Bone Mineral Densities (BMD), a basic indicator of femurs and tibiae, were measured using Dual Energy X-ray Absorptometry (DEXA). Results demonstrated that decreasing Ca intakes reduced bone formation markers, CICP (p<0.01) and BAP (p<0.05) and enhanced bone resorption marker, Pyd (p<0.05) significantly. Data revealed that supplement of soy extract highly elevated serum CICP (p<0.01) and BAP only with 1/4 Ca diets (p<0.05), however, suppressed the serum Pyd with 1/2 Ca diets. The bone sections also showed that calcium deficiency decreased OB numbers, thicknesses of growth plate, bone volume, MAR and increased OC numbers significantly, especially in CaS group comparing with others. Results also showed that supplement of soy extract could enhance the numbers of OB and the thicknesses of growth plate in tibiae (p<0.05). MAR showed a similar trend as BMD (p<0.05). Data demonstrated that increasing intake of Ca and/or soy extract enhanced the BMD of femurs and tibiae (p<0.05). It was also observed that ovariectomy significantly reduced the concentrations of serum CICP and BAP, and enhanced Pyd and NTx significantly (p<0.05) comparing with normal rats fed same diet (CaS). Both Ca and soy extract intakes could enhance bone growth and BMD in growing rats. Dietary supplement of soy extract can enhance Ca bioavailability and bone formation, and reduce bone resorption. Male rats got similar trend with females. In conclusion, serum CICP, BAP, Pyd, OB numbers, thicknesses of growth plate, bone volume, MAR can be the bone biomarkers for growing bones. However, serum CICP (best), BAP and Pyd can be simple and sensitive markers to evaluate the effect of a heath food or nutraceutical on growing bones.