运动对生长期小鼠骨代谢及PDGF介导的ERK信号通路的影响

Effects of Different Exercise on Bone Metabolism and PDGF via ERK Signaling of Growing Male Mice

目的:研究两种不同运动方式对生长期雄性小鼠骨的影响,以探讨运动影响骨形成的分子机制,为运动促进骨形成提供理论机制和实践方法。方法:将48只4周龄雄性小鼠随机分成3组,即对照组(C组)、游泳组(S组)和下坡跑组(D组),每组16只。游泳组在水深45 cm的泳池中运动8周,下坡跑组在跑台上运动8周,运动方案为0.8km/h,45 min/day,5 d/week,坡度-9°。8周结束后,断颈椎处死小鼠,摘眼球取血并检测相关酶活性,取相关骨组织利用双能X线、RT-PCR、Wsetern-blotting等方法对骨密度、相关细胞因子mRNA和蛋白表达等进行检测。结果:D组骨密度值高于C组且存在显著差异(P<0.01);D组骨密度也高于S组,且存在显著差异(P<0.01)。D组血清中ALP浓度显著高于C组(P<0.01),也显著高于S组(P<0.01)。S组血清中TRACP浓度低于C组,但无显著差异(P>0.05);D组血清中TRACP浓度显著低于C组(P<0.05),D组血清中TRACP浓度也较S组为低,但无显著差异(P>0.05)。S组间充质干细胞(MSCs)的增值能力显著高于C组;D组MSCs的增值能力显著高于C组。用RTPCR检测,S组骨组织中BMP-2表达显著上调,且高于C组(P<0.05);D组骨中BMP-2表达显著上调高于C组(P<0.05),与S组相比表达上调,但不具有显著差异(P>0.05)。S组骨中c-fos的表达上调,且显著高于C组(P<0.05)。D组骨中PDGFb、c-fos、ERK1的表达上调,且显著高于C组(P<0.05),D组骨组织中PDGFb、ERK1的表达上调,且显著高于S组(P<0.05)。S组中P-ERK蛋白的相对表达量显著高于C组(P<0.05),D组骨组织中P-ERK蛋白的相对表达量显著高于C组(P<0.01),虽也高于S组(P>0.05),但差异不具有显著性。结论:1)下坡跑相比游泳运动在促进生长期小鼠的骨密度增加和骨代谢增强效果更佳。2)下坡跑运动相比游泳运动能更好地促进骨髓间间充质干细胞诱导分化成骨细胞的能力。3)运动可以通过激活PDGFb介导的ERK信号通路的相关细胞因子的表达,进而调节和促进骨形成。

Objective： The aim is to study two exercise modes on the effects of growing male mice bone and try to provide some basic theoretical properties for bone remolding by exercise at growing stage. Methods ：48 mice were equally divided into control group （C）, swimming group （S） and downhill running group （D）. The exercise of S group is swimming in the pool with 45cmqevel of water for 8 weeks. The exercise of D group is downhill running in the condition of 0. 8 km/h, 45 rain/day,5 days/week and treadmill slope of -9~. After 8 weeks exercise,all of the 48 mice were executed for blood and bone tissue samples. Results： After 8 weeks of exercise, BMD of D group is significantly higher than that of both C group （P 〈0. 01 ） and S group （P 〈0.01 ）. Blood ALP of D group is significantly higher than that of both C group （P 〈 0. 01 ） and S group （P 〈0. 01 ）. TRACP of S group is lower than that of C group,but there is no obvious difference （P 〉 0. 05 ）. TRACP of D group is significantly lower than that of C group （ P 〈 0. 05 ）. TRACP of D group is lower than that of S group, but there is no obvious difference （ P 〉 0. 05 ）. The MSCs proliferation abilities of D group and S group are higher than that of C group. Using RT-PCR test, the expression of osteoblast BMP-2 in S group is up-regulated significantly and higher than that of C group （ P 〈 0.05 ）. The expression of osteoblast BMP-2 in D group is up-regulated significantly and higher than that of C group （P 〈0. 05） ,but no obvious difference compared with S group（P 〉0.05）. The expression of c- fos in S group is significantly higher than that of C group （ P 〈 0. 05 ）. The expression of PDGFb, c-fos, ERK1 in D group is significantly higher than that of C group （ P 〈 0. 05 ）. The expression of PDGFb, ERK1 in D group is significantly higher than that of S group（ P 〈0. 05 ）. The phosphorylation ERK protein in S group is significantly higher than that of C group （P 〈 0. 05 ） and the phosphorylation ERK protein in D group is significantly higher than C group（ P 〈 0. 01 ）, also higher than that of S group but no obvious difference. Conclusions ： 1 ） Downhill running is more effective than swimming on pro- moting bone metabolism and bone mineral density of growing mice. 2） Downhill running is better than swimming on the proliferation of MSCs. 3） Exercise can regulate and promote bone formation by activating the gene expression and protein expression through the pathway of PDGFb via ERK cell signals.