利用Ca-41标记内源钙库法开展大鼠的钙吸收率研究

Calcium is an essential element that plays important roles in physiologic adjustment for human body. The losses of calcium content of bone will cause osteoporosis and other diseases. Calcium supplement is becoming more and more popular. However, recent studies have shown that some other diseases may be caused by excess calcium supplement（especially for patients with osteoporosis）.So, the accuracy of calcium absorption rate measurement is very meaningful for reasonable calcium supplement and prevention diseases of calcium metabolism. Due to the poor distinction of calcium source, lower measurement sensitivity and radioactive damage, etc for the traditional calcium absorption rate measurement technique, it is difficult to carry out the accurate, system, long-term research work. Based on the high sensitivity of Ca-41 measurement with accelerator mass spectrometry and the innovative methods of Ca-41 labeling endogenous calcium, the calcium absorption rate of normal and osteoporosis rats will be studied in this work. With the standard rat model, tracing and measurement, the labeling endogenous calcium with Ca-41 can fundamentally solve the shortage of traditional biological tracer technique. The project will systematically study influence factors on calcium absorption and accurately determine the calcium absorption rate. These studies can provide the basis for reasonable supplement of calcium and calcium intakes reference for Chinese people.

钙是人体的必需元素，参与众多的生命生理调控过程。骨钙的流失可以导致骨质疏松症（OP）等多种疾病，补钙成为流行。但最近的研究表明生物体（特别是骨质疏松生物体）摄入过量的钙可能会引起一些其它疾病。因此，准确测量生物体的钙吸收率，对于合理补钙和预防钙代谢疾病具有重要意义。传统的钙吸收率测定方法存在着钙源区分不清、测量灵敏度低、放射性损伤等问题，难以开展准确、系统、长期的研究工作。本项目利用加速器质谱技术测量长寿命放射性核素Ca-41灵敏度高的特点，通过Ca-41标记体内钙库的新方法，开展正常及骨质疏松大鼠对钙吸收率的准确测定。通过标准化的模型建立、示踪方法与测定，Ca-41体内钙库标记方法可以从根本上解决传统生物示踪技术的不足。本项目将系统研究影响钙吸收的因素，准确测定钙吸收率，从而为合理补钙、建立适宜于中国人的钙参考摄入量标准提供研究基础。

准确测定钙的吸收率对于药物评价和治疗骨质疏松具有重要意义。本工作基于放射性核素Ca-41半衰期长辐射剂量小等优点开展了有特色的内源钙库法钙吸收率测定的方法研究。本工作首先利用正常大鼠通过Ca-41示踪剂的标记、样品采集样和测量，得到了基于内源钙库法对不同钙剂量和不同钙剂形式的钙的吸收率；然后开展了对骨质疏松大鼠钙吸收率的测定研究，通过骨质疏松大鼠模型的建立，Ca-41生物标记，样品的采集和测量得到了内源钙库法对骨质疏松大鼠在不同药物作用下钙吸收率的测定。本工作成功建立了基于内源钙库法对钙吸收率的测定，并实现了在药物作用下钙吸收的评价，为开展钙的真实吸收率和药物评价提供了更为准确的实验技术和方法