中文摘要：

目的 应用骨形态计量学,研究不同浓度钠离子对幼鼠骨骼生长的影响及其机制.方法 5周龄雌性SD大鼠18只,随机分为3组,分别喂饲含钠量不同的鼠粮,正常组含钠1%,高钠组含钠8%,低钠组含钠0.13%,连续喂养60 d.每天监测饮水量、食量及定期测量体重.实验结束,动物处死取左侧胫骨分成两段,进行不脱钙骨包埋,骨形态计量学分析骨生长情况.结果 胫骨上段松质骨：静态参数显示低钠组骨小梁面积百分数高于正常组（P〈0.05）,高钠组与正常组差异无统计学意义,而高钠组较低钠组骨小梁厚度减小（P〈0.05）;动态参数显示低钠组与正常组比较,骨形成率明显升高（P〈0.05）,破骨细胞数量及其贴壁周长明显降低（P〈0.05）;高钠组与正常组相比,差异无统计学意义.胫骨中段皮质骨：静态参数各组间差异无统计学意义;动态参数中,与正常组相比,低钠组骨内膜骨吸收周长降低（P〈0.05）,高钠组骨内膜骨吸收周长升高（P〈0.05）,高钠组与低钠组相比骨内膜骨吸收周长升高（P〈0.01）,骨内膜骨形成率升高（P〈0.01）.结论 低钠和高钠对幼年鼠不同部位骨骼的影响不同,低钠饮食有利于幼鼠骨骼生长,其机制为增加松质骨的骨形成,抑制骨吸收;但高钠饮食对幼年鼠影响不一致,可能与个体基因背景有关.

英文摘要：

Objective To study the effects and mechanism of sodium on bone growth in immature female rats. Methods Thirty - six 5 - week - old female SD rats were randomly divided into 3 groups ： low dose sodium group （ LDS, 0. 13% NaC1） , normal dose group （NDS, 1% NaC1） , and high dose sodium group （HDS, 8% NaC1）. All doses of so- dium were given orally by food for 60 days. The left tibia （ proximal tibia metaphyses, PTM）, middle （ middle part of tibia shaft, TX） were taken for bone histomorphometry in the experiment. Results In PTM, the trabecular bone area ratio （BV/TV） and trabecular thickness were significantly increased in LDS group, comparing with those in HDS group （ P 〈 0.05 ）. In LDS group, the bone formation rate （BFR/TV） was significantly increased, while the osteoclast count and surface perimeter were significantly reduced, comparing with those in NDS group （P 〈 0. 05 ）. However, no significant difference was founded in bone formation rate, osteoclast count or suface perimeter between HDS group and NDS or LDS group. In Tx, no significant difference in cortical static parameters was revealed among the three groups. However, dynamic data showed that HDS enhanced endosteal bone resorption, which was depressed by LDS, when comparing with that in NDS group. Significant increase of endostral bone resorption and BFR were revealed in HDS group, when comparing with those in LDS group （P 〈 O. 05 ）. Conclusion Sodium in different concentrations effects on bone growth in various patterns. LDS improves bone formation and inhibits bone resorption. However, HDS effects variously, which may be due to individual variation.