鲫鱼卵唾液酸糖蛋白对去卵巢大鼠骨质疏松症的改善作用

目的：从鲫鱼卵中提取唾液酸糖蛋白,研究其对去卵巢大鼠骨质疏松症的改善作用,并探究其作用机理。方法：采用切除大鼠双侧卵巢的方法建立骨质疏松症大鼠模型,灌胃鲫鱼卵唾液酸糖蛋白（400 mg/（kg·d））90 d后,分别检测大鼠尿液骨吸收指标（脱氧吡啶啉、钙、磷）、血清骨吸收指标（抗酒石酸酸性磷酸酶、组织蛋白酶K）、血清骨生成指标（骨源性碱性磷酸酶、骨钙素、Ⅰ型前胶原羧基端前肽）以及血清骨保护素（osteoprotegerin,OPG）、核因子κB受体活化因子（receptor activator for nuclear factor-κB,RANK）、核因子κB受体活化因子配体（receptor activator for nuclear factor-κB ligand,RANKL）含量。结果：鲫鱼卵唾液酸糖蛋白能显著降低骨质疏松症大鼠尿液脱氧吡啶啉（P＜0.01）、钙（P＜0.01）、磷（P＜0.01）含量和血清抗酒石酸酸性磷酸酶（P＜0.01）、组织蛋白酶K（P＜0.01）活性,防止大鼠骨吸收;显著降低血清骨源性碱性磷酸酶（P＜0.01）活性和骨钙素（P＜0.01）、Ⅰ型前胶原羧基端前肽（P＜0.01）含量,抑制大鼠高骨转换速率;显著上调OPG（P＜0.01）含量,下调RANKL（P＜0.01）含量,降低RANKL/OPG比值,抑制破骨细胞增殖分化,降低骨吸收。结论：鲫鱼卵唾液酸糖蛋白具有改善去卵巢大鼠骨质疏松症的作用,其作用机理可能与下调RANKL/OPG比值有关。     

Sialoglycoprotein isolated from Carassius auratus eggs promotes osteoblast differentiation via targeting the p38 mitogen‐activated protein kinase‐dependent Wnt/β‐catenin and BMP2/Smads pathways

In the current study, sialoglycoprotein isolated from eggs of Carassius auratus promoted MC3T3‐E1 cells proliferation and differentiation, as assessed by MTT, mineralized nodule formation in vitro, as well as new osteoid formation in neonatal mouse calvarias ex vivo. Further research revealed that Ca‐SGP facilitated osteogenesis via activating BMP2/Smads, Wnt/β‐catenin, and p38MAPK signaling pathways. What is more, p38MAPK inhibitor SB203580 down‐regulated related mRNA and protein expression of BMP2/Smads and Wnt/β‐catenin signaling pathways, suggesting that p38MAPK pathway might be important for activation of BMP2/Smads and Wnt/β‐catenin pathways in Ca‐SGP‐induced osteoblastic differentiation. In conclusion, it was demonstrated that Ca‐SGP promotes osteoblasts differentiation via activating p38MAPK‐dependent BMP2/Smads and Wnt/β‐catenin signaling pathways, which may provide basis for the use of Ca‐SGP as a potential agent to treat bone loss‐associated diseases such as osteoporosis.

Practical application

Carassius auratus eggs are one of the major by‐products during fish processing and contain sialoglycoprotein which plays an important role in biological functions. However, they have not been high‐value utilized. This study demonstrated that Sialoglycoprotein isolated from eggs of C. auratus (Ca‐SGP) promoted MC3T3‐E1 cells proliferation, differentiation and mineralized nodule formation in vitro, as well as neonatal mouse calvarias formation ex vivo, which may provide basis for a novel application of C. auratus eggs as a functional food used to accelerate bone formation.     

燕窝唾液酸糖蛋白间接竞争酶联免疫检测方法的建立

目的 建立间接竞争酶联免疫（indirect competitive enzyme linked immunesorbent assay，IC-ELISA）检测燕窝中唾液酸糖蛋白的分析方法。方法 以唾液酸糖蛋白为抗原，制备单克隆抗体，对IC-ELISA步骤中相关参数进行优化，确定最佳反应条件。结果 最佳包被抗原为1∶2000，抗体稀释倍数为1∶5000；封闭液浓度为1%牛血清白蛋白（bovine serum albumin，BSA），封闭时间为150 min；竞争时间30 min；酶标二抗浓度稀释倍数为1∶1000，孵育时间30 min；显色时间为10 min。建立的IC-ELISA检测方法半抑制浓度(50% inhibition concentration，IC50)为8.61 μg/mL，线性范围为2.23~33.25 μg/mL，回收率为82.7%~92.0%，相对标准偏差(relative standard deviation，RSD)为1.7%~8.9%。结论 该方法灵敏度较高、特异性强，可以有效地鉴别假冒伪劣燕窝产品，具有较好的实际应用价值。