血清和尿液中钙离子浓度作为骨丢失评价指标的初步探讨

目的探讨体液中钙离子浓度作为早期评价骨丢失间接指标的可行性。方法采用尾悬吊模拟失重性骨丢失为动物模型,悬吊组和对照组各8只3月龄SD雌性大鼠,悬吊时间为3周。大鼠每2 d收集1次尿液;每周麻醉1次称重,并使用骨密度仪测量股骨和胫骨处的骨密度;实验结束大鼠麻醉后动脉取血,分离血清,采用离子敏感电极技术检测尿液和血清中钙离子浓度。分离大鼠右侧股骨和胫骨,烘烤后称量骨干质量和骨灰质量。结果大鼠尾悬吊1周后体重明显下降(P<0.01);尿液中钙离子浓度显著升高(P<0.01,P<0.001);股骨的骨密度在第2周和第3周有明显下降(P<0.001);股骨骨干和骨灰质量也有明显变化(P<0.05)。结论尿液中钙离子浓度可以作为评价骨丢失的间接指标。

Preliminary Exploration on Ca2+ Concentration in Blood Serum and Urine as Evaluation Indicator of Bone Loss

Objective To determine the Ca2+ concentration in blood serum and urine and explore the feasibility as the early phase indirect indicator for evaluation of bone loss.Methods Tail suspension(TS) was used as the animal model of bone loss under simulated weightlessness.Eight three-month SD female rats were in each group(TS and Con group).Urine samples were collected every two days.After 3 weeks,the rats were anesthetized,their body weight were weighed,the bone mineral densities(BMD) of femur and tibia were determined with the dual-energy X-ray absorptiometry device and the artery blood samples were taken.The blood samples were centrifuged and the serum was separated.The Ca2+ concentration of urine and serum were measured with the ion-selective electrode technique.The femur and tibia in the right side were taken and cleaned carefully and put into the resistance furnace.The bone dry mass and bone ashes mass were weighed.Results The body weight had an obvious downtrend after one week of TS(P<0.01) and the urine Ca2+ concentration had a clear rise(P<0.01,P<0.001).The BMD of femur declined obviously on the second and third week(P<0.001).Bone dry mass also changed obviously(P<0.05).Conclusion Ca2+ concentration in urine can be used as the indirect indicator for evaluation of bone loss.