低磷食物对模拟失重小鼠后肢骨骨质丢失防治作用的探讨

摘要

目的 初步探讨低磷食物对模拟失重下小鼠骨丢失防治的可能性及防治效果,为后期可能的临床应用提供实验依据.方法 利用尾部悬吊法模拟失重.将24只C57BL/6雌性小鼠随机分为四组,即对照(CON)组、对照低磷(CON-LP)组、悬尾(SUS)组及悬尾低磷(SUS-LP)组,每组6只.4周实验期满后取小鼠后肢骨标本,通过Micro-CT扫描分析比较各组小鼠股骨的骨体积分数(bone volume frac-tion,BV/TV)、骨小梁密度(trabecular density,Tb.Density)等骨密度参数,骨小梁厚度(trabecular thickness,Tb.Th)、平均骨小梁数(trabecular number,Tb.N)等骨形态学参数.通过抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色、碱性磷酸酶(alkaline phosphatase,ALP)染色和丽春红三色(Ponceau S)染色对各组小鼠胫骨生长发育和改建情况进行组织形态学观察.结果 Micro-CT结果显示,CON-LP组与CON组比较:骨密度参数BV/TV和Tb.Density减小(P<0.05),形态学参数Tb.Th增高和Tb.N减少(P<0.05).SUS-LP组与SUS组比较:骨密度参数BV/TV和Tb.Density减小(P<0.05),形态学参数Tb.Th和Tb.N减少(P<0.05).染色结果显示:悬尾的小鼠(SUS组、SUS-LP组)与地面的小鼠(CON组、CON-LP组)比较,骨小梁出现明显的骨吸收,Tb.N减少、骨小梁间距变大.CON-LP组与CON组比较,Tb.Density减低、Tb.N减少.SUS-LP组与SUS组比较,骨小梁变细、Tb.N减少.结论 低磷食物对模拟失重下小鼠后肢骨骨丢失防治效果不明显,甚至可能产生不利的后果.%Objective To investigate whether low phosphate (Pi) diet has a preventive and therapeutic effect on bone loss of mice hindlimb under simulated weightlessness. Methods Twenty female C57BL/6 mice were divided into 4 groups randomly:the control group (CON), the control mice with low Pi diet (CON-LP), the tail suspension group (SUS), and the tail suspension group with low Pi diet (SUS-LP). After 4-week experiments, all mice were sacrificed and the right hindlimbs were removed as the specimens. The bone volume fraction (BV/TV), trabecular bone thickness (Tb.Th), trabecular bone number (Tb.N) and average density CT value (Tb. Density) in 4 groups were compared by micro-CT scanning, reconstruction and analysis. Meanwhile, TRAP, ALP and Ponceau S stains were used for the proximal tibia slices to observe the histomorphologic changes. Results Micro-CT showed that Tb.Th in CON-LP group was higher than that in CON group (P<0.05). As compared with the SUS group, BV/TV, Tb.Density, Tb.Th and Tb.N in SUS-LP group were significantly decreased (P<0.05). TRAP, ALP and Ponceau S staining showed a significant difference among the 4 groups. As compared with the CON/CON-LP group, the trabecular bone loss was significant in the SUS/SUS-LP group. And the number of trabecular bone was less and the trabecular bone separation distance was larger than in CON/CON-LP group. As compared with the CON group, the trabecular bone density and the number of trabecular bone were reduced in the CON-LP group. As compared with the SUS group, the trabecular bone width was thinner and the trabecular bone number was less in the SUS-LP group. Conclusion The results indicate that the preventive and therapeutic effect to hind limb bone loss of mice under conditions of simulated weightless-ness with low phosphate diet was not feasible, and it might even be harmful to do so.