代谢肥胖对雄性大鼠骨代谢影响△

Effects of metabolic obesity on bone metabolism in male rats

摘要:

[目的] 探讨代谢肥胖对雄性 SD 大鼠青年期 (17 周龄) 和成年期 (27 周龄) 骨代谢的影响。[方法] 5 周龄雄性 SD 大鼠 40 只，按随机数字表法随机分成普食组 (normal diet, ND 组)、高脂组 (High-fat diet, HFD 组)，分别给予 ND 和 HFD 饲养至 17 周和 27 周。检测血清骨代谢标志物，行微型 CT 检查和三点弯曲力学测试。[结果]两组大鼠 17 周龄时血 Ca、P、 PINP、CTX 的差异均无统计学意义(P＞0.05)。27 周龄时 HFD 组大鼠 PINP 显著小于 ND 组(P＜0.05)，而 CTX 显著大于 ND 组 (P＜0.05)。随周龄增加，大鼠体重及肌肉量显著增加 (P＜0.05)。与 ND 组相比，17 周龄 HFD 组大鼠的 Tb.vBMD、Tb.BV/TV、 Tb.N 均显著减少(P＜0.05)，而 Tb. Sp 显著增加(P＜0.05)。27 周龄 HFD 组大鼠的 Tb. vBMD、Tb. BV/TV、Tb. Th、Tb. N 均显著减少(P＜0.05)，Tb. Sp 和 SMI 显著增加(P＜0.05)。与 17 周相比，27 周 ND 组最大负荷、最大断裂负荷、能量吸收、韧性、极限拉伸强度、弹性模量均显著增加(P＜0.05)，而 HFD 组除最大负荷和能量吸收显著增加(P＜0.05)外，其余指标差异无统计学意义 (P＞0.05)。17 周时，两组上述指标的差异均无统计学意义 (P＞0.05)，27 周时，HFD 组上述指标较 ND 组均显著减少 (P＜ 0.05)。[结论]代谢肥胖可降低骨形成标志物，升高骨吸收标志物，自青少年开始出现骨微结构改变，至成年骨微结构损伤加重，并出现了骨强度下降。

关键词:代谢肥胖;骨代谢标志物;微型 CT;三点弯曲试验

Abstract:

[Objective] To explore the effects of metabolic obesity on bone metabolism in male Sprague-Dawg rats in youth (17 weeks of age) and adulthood (27 weeks of age). [Methods] Forty 5-week-old male SD rats were randomly divided into the normal diet (ND) group and high-fat diet (HFD) group, and were fed with ND and HFD until 17 and 27 weeks, respectively. The serum bone metabolism markers were detected, micro CT examination and three point bending mechanical test were performed. [Results] Although there were no significant differences in serum Ca, P, PINP and CTX between the two groups at 17 weeks of age (P＞0.05), the HFD group had significantly lower PINP, while significantly higher CTX than the ND group at 27 weeks of age (P＜0.05). The body weight and muscle mass of the animals significantly increased with age (P＜0.05). Compared with the ND group, the Tb.vBMD, Tb.BV /TV and Tb.N significantly decreased (P＜0.05), while Tb. Sp significantly increased in the HFD group at 17 weeks of age (P＜0.05). In addition, the Tb.vBMD, Tb.BV /TV, Tb.th, Tb.n significantly de- creased (P＜0.05) while the Tb. Sp and SMI significantly increased in HFD group at 24 weeks of age (P＜0.05). Compared with those at 17 weeks of age, the maximum load, maximum fracture load, energy absorption, toughness, ultimate tensile strength and elastic modulus signifi- cantly increased in the ND group at 27 weeks of age (P＜0.05), while the maximum load and energy absorption significantly increased in the HFD group (P＜0.05), without significant difference in other biomechanical indexes (P＞0.05). Despite there was no significant difference in the above indexes between the two groups at 17 weeks of age (P＜0.05), HFD group got significantly decreased above items compared with the ND group at 24 weeks of age (P＜0.05). [Conclusion] This metabolic obesity does reduce formation markers, while increase bone resorption markers. The bone microstructure changes appear in the adolescents, while the bone microstructure damage worsens in the adult with bone strength decreases

Key words:metabolic obesity; bone metabolic markers; micro-CT; three-point bending test