不同方式运动对生长期大鼠Ihh/PTHrP信号通路及骨纵向生长的影响

Effects of Different Exercise on Ihh/PTHrP Signaling Pathway and Bone Longitudinal Growth in Growing Rats

目的:探索不同方式运动对生长期大鼠Ihh/PTHrP信号通路相关分子表达及软骨内成骨导致骨纵向生长的影响。方法:将生长期大鼠随机分为对照组(C),游泳组(S),跑台组(R)和下跳组(D),进行6周不同方式的运动,利用MicroCT对骨组织形态学,以及各组生长板软骨细胞的Ihh、PTHrP免疫组化的阳性区域进行比较,利用RT-PCR、west-bloting检测细胞因子mRNA和蛋白表达。结果:1.只有下跳组大鼠股骨皮质骨骨密度有显著性增加(P<0.05)。2.R组和D组PTHrP mRNA的表达水平都有显著性上调(P<0.05);Ptc mRNA的表达水平,与C组相比,R组D组有显著性上调(P<0.05);Smo mRNA的表达水平组间无显著性差异(P>0.05)。3.Ihh蛋白表达水平与C组相比,R组和D组都有非常显著性增加(P<0.01),且D组与R组相比也有非常显著性增加(P<0.01);PTHrP蛋白表达水平与C组相比R组和D组都有非常显著性增加(P<0.01),与S组相比,R组有显著性增加(P<0.05),D组的有非常显著性增加(P<0.01)。4.生长板免疫组化结果比较,R组和D组肥大层软骨细胞的Ihh的阳性区域明显大于C组和S组,D组尤为明显,而且肥大软骨细胞排列有序,肥大效果明显。PTHrP免疫组化结果看,C组和S组软骨细胞的阳性区域没有Ihh免疫组化结果明显,R组和D组,尤其是D组,可以明显看出非肥大层的宽度也大于C组和S组,而且增殖软骨细胞排列有序,增殖阳性区域效果明显。Ihh mRNA的表达水平与C组比较,R组和D组都有非常显著性上调(P<0.01)。结论:下跳运动可显著激活Ihh/PTHrP信号通路,促进生长期大鼠生长板软骨内成骨,更有利于促进骨的纵向生长。

Objective:To explore the effects of different exercise modes on the expression of IHH/PTHrP signaling pathway related molecules and the longitudinal bone growth induced by intrachondral osteogenesis in growing rats.Methods:The growing rats were randomly divided into control group(C),swimming group(S),running group(R)and down jump group(D).After 6 weeks of exercise,the bone histomorphology and IHH,PTHrP immunohistochemical positive regions of chondrocytes in each group were compared.The mRNA and protein expression of cytokines were detected by RT-PCR and Western blotting.Results:1.Only the bone mineral density(BMD)of femur cortex increased significantly in the down jump group(P<0.05).2.The expression of PTHrP mRNA in group R and group D was significantly up-regulated(P<0.05);the expression level of PTC mRNA in group R was significantly higher than that in group C(P<0.05);there was no significant difference in the expression of smomrna between groups(P>0.05).3.Compared with group C,the expression of IHH protein in group R and group D was significantly increased(P<0.01),and that in group D was also significantly increased(P<0.01);compared with group C,the expression of PTHrP protein in group R and group D was significantly increased(P<0.01),compared with group S,the expression of IHH protein in group R was significantly increased(P<0.05),and that in group D was significantly increased(P<0.01).4.The IHH positive area of hypertrophic chondrocytes in group R and group D was significantly larger than that in group C and group S,especially in group D.The mast chondrocytes were arranged orderly and the effect of hypertrophy was obvious.The results of PTHrP immunohistochemistry showed that the positive area of chondrocytes in group C and group s was not as obvious as that in group IHH.The width of non hypertrophic layer in group R and group D,especially in group D,was larger than that in group C and group S.Moreover,the proliferative chondrocytes were arranged orderly and the effect of proliferation positive area was obvious.Compared with group C,the expression of IHH mRNA in group R and group D was significantly increased(P<0.01).Conclusion:Jumping exercise can significantly activate Ihh/PTHrP signaling pathway,more conducive to promote the growth plate endochondral osteogenesis and the longitudinal growth of bone.