代谢肥胖对雄性大鼠骨代谢影响

Effects of metabolic obesity on bone metabolism in male rats

[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(normaldiet,ND组)、高脂组(High-fatdiet,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(PP<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。

[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 decreased(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 significantly 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.