Zhao Yan, Zou Bing, Shi Zhenyu, Wu Qiong, Chen Guo-Qiang
Protein Science Laboratory of Ministry of Science, Department of Biological Science and Biotechnology, Tsinghua University, Beijing 100084, China.
Biomaterials. 2007 Jul;28(20):3063-73. doi: 10.1016/j.biomaterials.2007.03.003. Epub 2007 Mar 14.
3-hydroxybutyrate (3HB), one of the degradation products of microbial biopolyesters polyhydroxyalkanoates (PHA), is a high energy metabolic substrate in animals. This study evaluated the effects of 3HB on growth of osteoblasts in vitro and on anti-osteoporosis in vivo. Alkaline phosphatase (ALP) assay, Van Kossa assay and Alizarin S red staining were used to study in vitro differentiation of murine osteoblast MC3T3-E1 cells. The intensity of in vitro cell differentiation measured in ALP was in direct proportion to the concentration of 3HB when it was lower than 0.01 g/L. Calcium deposition, a strong indication of cell differentiation, also showed an obvious increase with increasing 3HB concentration from 0-0.1g/L, evidenced by Alizarin red S staining and Van Kossa assay. RT-PCR also showed significantly higher expression of osteocalcin (OCN) mRNA in MC3T3-E1 cells after 3HB administration. In vivo study using female Wistar rats (3 months old, n=80) allocated into normal, sham-operated or ovariectomized (OVX) group that led to decreasing bone mineral density (BMD), bone histomorphometry and biomechanics compared with normal and sham groups, had demonstrated that 3HB increased serum ALP activity and calcium deposition, decreased serum OCN, prevented BMD reduction resulting from OVX. All these led to enhanced femur maximal load and bone deformation resistance, as well as improved trabecular bone volume (TBV%). In conclusion, 3HB monomer containing PHA can be effective bone growth stimulating implant materials.
3-羟基丁酸酯（3HB）是微生物生物聚酯聚羟基脂肪酸酯（PHA）的降解产物之一，是动物体内的一种高能代谢底物。本研究评估了3HB对体外成骨细胞生长和体内抗骨质疏松的影响。采用碱性磷酸酶（ALP）检测、范科萨（Van Kossa）检测和茜素红S染色法研究小鼠成骨细胞MC3T3-E1细胞的体外分化。当3HB浓度低于0.01 g/L时，以ALP测定的体外细胞分化强度与3HB浓度成正比。茜素红S染色和范科萨检测表明，作为细胞分化有力指标的钙沉积也随着3HB浓度从0至0.1g/L的增加而明显增加。RT-PCR也显示，给予3HB后，MC3T3-E1细胞中骨钙素（OCN）mRNA的表达显著升高。在体内研究中，将3月龄雌性Wistar大鼠（n=80）分为正常组、假手术组或去卵巢（OVX）组，与正常组和假手术组相比，去卵巢组导致骨矿物质密度（BMD）、骨组织形态计量学和生物力学下降，结果表明3HB可提高血清ALP活性和钙沉积，降低血清OCN，防止去卵巢导致的BMD降低。所有这些都导致股骨最大负荷和抗骨变形能力增强，以及小梁骨体积（TBV%）改善。总之，含3HB单体的PHA可成为有效的促进骨生长的植入材料。
