Iwamoto Jun, Seki Azusa, Nango Nobuhito
Department of Orthopaedic Surgery, Keiyu Orthopaedic Hospital, 1741 Hanetsuku-cho, Tatebayashi, Gunma, 374-0011, Japan.
Hamri Co., Ltd., 2638-2 Ozaki, Koga City, Ibaraki, 306-0101, Japan.
Calcif Tissue Int. 2016 Nov;99(5):535-542. doi: 10.1007/s00223-016-0180-0. Epub 2016 Jul 27.
Teriparatide (TPTD) is known to increase the cortical thickness and porosity. The purpose of the present study was to determine whether switching from TPTD to ibandronate (IBN) would be useful for improving cortical bone parameters as assessed using high-resolution quantitative computed tomography (HR-QCT) analyses in mature rabbits. Forty-two female New Zealand white rabbits (18-22 weeks old) were randomized into six groups of 7 animals each as follows: 4-week vehicle administration group, 4-week TPTD administration group (20 μg/kg, subcutaneously [s.c.], daily), 12-week vehicle administration group, 4-week TPTD administration + 8-week vehicle administration group, 4-week TPTD administration + 8-week lower-dose IBN administration group (20 μg/kg, s.c., every 4 weeks), and 4-week TPTD administration + 8-week higher-dose IBN administration group (100 μg/kg, s.c., every 4 weeks). After the 4- or 12-week experimental period, the cortical bone of the distal femoral diaphysis was processed for HR-QCT analysis. The 4-week TPTD administration increased the pore ratio, number, and density as well as the cortical area, thickness, and bone mineral content (BMC), without significant influencing the volumetric bone mineral density (BMD). The 4-week TPTD administration + 8-week vehicle administration decreased the pore ratio, number, and density as well as the cortical area and thickness, compared with the 4-week TPTD administration, but the pore ratio, cortical area, and thickness were still higher compared with the 12-week vehicle administration. The 4-week TPTD administration + 8-week higher-dose IBN administration, but not the 4-week TPTD administration + 8-week lower-dose IBN administration, increased the cortical area, thickness, BMC, and volumetric BMD and decreased the pore ratio, but not the pore number or density, compared with the 4-week TPTD administration + 8-week vehicle administration. These results suggest that higher-dose IBN after TPTD therapy has a beneficial effect on the BMC, volumetric BMD, cortical area, thickness, and porosity in mature rabbits.
已知特立帕肽（TPTD）可增加皮质骨厚度和孔隙率。本研究的目的是确定从TPTD转换为伊班膦酸盐（IBN）是否有助于改善成熟兔的皮质骨参数，这些参数通过高分辨率定量计算机断层扫描（HR-QCT）分析进行评估。42只雌性新西兰白兔（18 - 22周龄）被随机分为6组，每组7只动物，分组如下：4周赋形剂给药组、4周TPTD给药组（20μg/kg，皮下注射[s.c.]，每日）、12周赋形剂给药组、4周TPTD给药 + 8周赋形剂给药组、4周TPTD给药 + 8周低剂量IBN给药组（20μg/kg，皮下注射，每4周一次）和4周TPTD给药 + 8周高剂量IBN给药组（100μg/kg，皮下注射，每4周一次）。在4周或12周的实验期后，对股骨远端骨干的皮质骨进行HR-QCT分析。4周TPTD给药增加了孔隙率、孔隙数量和密度以及皮质骨面积、厚度和骨矿物质含量（BMC），而对体积骨密度（BMD）无显著影响。与4周TPTD给药相比，4周TPTD给药 + 8周赋形剂给药降低了孔隙率、孔隙数量和密度以及皮质骨面积和厚度，但孔隙率、皮质骨面积和厚度仍高于12周赋形剂给药组。与4周TPTD给药 + 8周赋形剂给药相比，4周TPTD给药 + 8周高剂量IBN给药增加了皮质骨面积、厚度、BMC和体积BMD，并降低了孔隙率，但未降低孔隙数量或密度，而4周TPTD给药 + 8周低剂量IBN给药则无此作用。这些结果表明，TPTD治疗后给予高剂量IBN对成熟兔的BMC、体积BMD、皮质骨面积、厚度和孔隙率有有益影响。
