钙、维生素D缺乏对幼鼠骨生长和成骨细胞功能的影响

目的：探讨钙与维生素D营养缺乏对幼鼠骨骼生长和矿化的影响及机制。方法：建立单纯钙缺乏、维生素D缺乏和钙与维生素D同时缺乏的幼鼠动物模型，追踪其长骨的生长发育，并监测血清Ca,P,25-ODH3,骨碱性磷酸酶（B－ALP）水平及骨矿含量的构成的改变；观察反映骨形成和成骨细胞功能的生化标志－血清骨钙素水平。结果：钙缺乏、维生素D缺乏和两者同时缺乏大鼠的长骨生长发育明显落后于正常大鼠；其胫骨重、骨灰重均显著降低；对骨矿成分的分析显示，除K以外Ca,P,Mg,Na均有不同程度减少；实验组大鼠的血清骨钙素水平随实验期延长呈进行性下降。结论：钙和维生素D缺乏影响成骨细胞的功能，使骨形成和矿化过程受阻，从而导致骨骼生长发育质和量的异常。

Bone Formation and Osteoblast Activity in Young Growing Rats Fed Low Calcium or Vitamin D Deficient Diets

To investigate the effects and mechanisms of dietary calcium or vitamin D deficiency on bone growth and mineralization in young growing rats. Four groups of fifteen weaning male wistar rats were fed normal(0.5% Ca,2000IU/kg vitD),low calcium(0.15%) Ca,2000IU/kg VitD),vitamin D deficient (0.5% Ca,without VitD) or both low calcium and vitamin D deficient (0.15% Ca, without VitD) diets.Animals were housed in stainless steel hanging cages in a lightcontrolled environment and porvided distilled water ad libitum for 6 week.One third of rats in each group were killed at 0,3,6, week respectively.Serum Ca,P,25 OHD 3,none specific alkaline phosphatase and serum osteocalcin(OC) levels were assayed.Tibia and femur length,fat free dry bone weight,ash weight and bone mineral composition were also determined. After 3 week depletion,bone growth and mineralization in the three experiment groups lagged behind normal rats significantly.The tibia and femur length,fat free dry bone weight,ash weight were lower compared with those of corresponding controls.All measured bone mineral levels including Ca,P,Mg,Na were also reduced except for potassium.Serum OC levels were decreased as the experiment time went on. Conclusions] Calcium or vitamin D deficiency during the period of skeletal development compromises both the quantity and quality of bone.The impaired bone growth seems to be mediated through the effects on osteoblast activity.