不同钙含量饲养条件下氟中毒对大鼠骨转换的影响

Effects of excess fluoride on bone turnover under conditions of diet with different calcium contents

目的研究不同钙含量饲养条件下过量氟对骨转换的影响。方法用富钙平衡饲料与低钙偏食饲料分别饲养大鼠，经饮水给氟１００ｍｇ／Ｌ，进行为期２个月和１年的实验观察。结果偏食低钙条件下饮高氟水２个月，引起骨软化和骨质疏松，成骨与破骨活动高度活跃，血清碱性磷酸酶（ＡＬＰ）、骨钙素、甲状旁腺激素升高。富钙平衡饲料饲养条件下饮高氟水２个月显示轻度成骨活跃；饮高氟水１年形态计量显示骨小梁平均宽度增加，ＡＬＰ活性升高。结论过量氟对骨骼的基本毒性作用是造成骨转换增高；低钙与高氟在引起骨转换增高方面具有一致性，这是膳食低钙能使氟骨症加重的发病学基础。

Objective To study the effects of excess fluoride on bone turnover under conditions of diet containing different amount of calcium. Methods The experiment was performed on rats raised on a balanced diet with adequate calcium or a monotonous diet with low calcium and given amount of fluoride in their drinking water (F, 100mg/L) for 2 months or 1 year. Results Osteomalacia, osteoporosis and accelerated bone turnover were observed with elevated serum alkaline phosphatase (ALP), osteocalcin (BGP) and parathyroid hormone (PTH) in rats fed on low calcium diet and fluoridized water for 2 months.In the rats fed on adequate calcium diet and fluoridized water for 2 months, only slightly increased osteoblastic activity was found while the average width of trabecular bone was increased with elevated serum ALP activity in rats raised on the same diet and water for 1 year. Conclusions The basic effect of excess fluoride on bone is the causation of a high bone turnover state which can also be induced to a milder extent by low calcium diet itself. Therefore,the formation of a high bone turnover state is the pathogenetic basis for low dietary calcium intake to exacerbate the severity of skeletal fluorosis.