Fukuoka H, Kiriyama M, Nishimura Y, Higurashi M, Suzuki Y, Gunji A
Department of Maternal and Child Health, University of Tokyo.
Acta Physiol Scand Suppl. 1994;616:37-41.
Immobilization induces abnormal bone metabolism and rapid decalcification. Measurements of bone mineral content disclosed rapid decalcification, especially in lumbar vertebral and metacarpal bones in our short-term 20-day bed rest study. Many factors could contribute to the marked demineralization. The activities of osteoclasts and osteoblasts were studied by following serum levels of tartrate-resistant acid phosphatase and alkaline phosphatase, biomarkers for osteocyte activity. There were no alterations in these enzymes during bed rest. However, urinary excretion of pyridinium cross-links, resorption markers of bone matrix itself, increased by day 10 with subsequent decrease at day 20. So decalcification was induced without any relation to osteoclast activity. As cytokines strongly modulate the function of osteoclasts, peripheral monocyte release of interleukin 1 alpha and tumor necrosis factor alpha were assayed to determine the contribution to this rapid demineralization. Cytokines were released transiently by day 7 and later rapidly decreased. However, there was no correlation between cytokine release and bone matrix resorption.
固定会导致异常的骨代谢和快速脱钙。在我们为期20天的短期卧床休息研究中，骨矿物质含量测量显示出快速脱钙，尤其是在腰椎和掌骨中。许多因素可能导致明显的脱矿质作用。通过跟踪血清中抗酒石酸酸性磷酸酶和碱性磷酸酶（成骨细胞活性的生物标志物）的水平，研究了破骨细胞和成骨细胞的活性。卧床休息期间这些酶没有变化。然而，吡啶交联物（骨基质自身的吸收标志物）的尿排泄在第10天增加，随后在第20天下降。因此，脱钙的诱导与破骨细胞活性无关。由于细胞因子强烈调节破骨细胞的功能，因此检测了外周单核细胞释放的白细胞介素1α和肿瘤坏死因子α，以确定其对这种快速脱矿质作用的影响。细胞因子在第7天短暂释放，随后迅速下降。然而，细胞因子释放与骨基质吸收之间没有相关性。
