EFFECTS OF EXERCISE AND IMMOBILIZATION ON BONE-FORMATION AND RESORPTION IN YOUNG-RATS
EFFECTS OF EXERCISE AND IMMOBILIZATION ON BONE-FORMATION AND RESORPTION IN YOUNG-RATS
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DOI：
10.1152/ajpendo.1993.264.2.e182
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发表时间：
1993-02-01
影响因子：
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通讯作者：
ALOIA, JF
中科院分区：
文献类型：
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作者：
YEH, JK;LIU, CC;ALOIA, JF
在以下三组6周龄雌性大鼠中研究了体力活动对骨形成和骨吸收的影响：30个对照组，24个坐骨神经去固定组和28个跑台运动组。通过Ca-45保留、Ca-45排泄、骨钙含量、骨体积、再吸收表面和通过四环素标记评估的骨形成率来确定骨形成和再吸收。在研究前，对每只动物静脉内给予Ca-45（30 μ Ci），然后在6周的实验期间测定尿和粪便中同位素的排泄。运动导致Ca-45总排泄量最初增加（P < 0.01），随后下降至低于对照水平（P < 0.001）。第6周时，运动组股骨Ca-45潴留和钙含量高于对照组。胫骨骨膜成骨率在32-41天显著增加（P < 0.01）。制动后，大鼠Ca-45周排泄量持续高于对照组（P < 0.01），股骨Ca-45存留量（P < 0.05）和钙含量（P < 0.01）低于对照组。在前31天，骨膜和骨内膜骨形成率低于对照组。总之，运动在年轻生长的大鼠与骨吸收的初始增加，然后减少，而活跃的骨形成是持续的。制动6周导致骨吸收增加和骨形成迅速下降。
The influence of physical activity on bone formation and resorption was studied in the following three groups of 6-wk-old female rats: 30 controls, 24 sciatic denervation immobilized, and 28 treadmill exercised. Bone formation and resorption were determined from Ca-45 retention, Ca-45 excretion, bone calcium content, bone volume, and resorbing surface and bone formation rate assessed by tetracycline labeling. Ca-45 (30 muCi) was administered intravenously to each animal before study, and the excretion of isotope in the urine and feces was then determined during the 6-wk experimental period. Exercise resulted in an initial increase in total excretion of Ca-45 (P < 0.01) followed by a drop to below control levels (P < 0.001). The femoral Ca-45 retention and calcium content of the exercised group were higher than that of the control group at week 6. Periosteal bone formation rate in the tibia was enhanced during days 32-41 (P < 0.01). With immobilization, the weekly excretion of Ca-45 was persistently higher (P < 0.01), and the femoral Ca-45 retention (P < 0.05) and calcium content (P < 0.01) were lower than the control group. Periosteal and endosteal bone formation rates were lower than in the controls over the first 31 days. In conclusion, exercise in young growing rats is associated with an initial increase and then a decrease in bone resorption while active bone formation is sustained. Immobilization for 6 wk results in an increase in bone resorption and a rapid fall in bone formation.