Abstract:Objective To evaluate the effect of parathyroid hormone in an asymmetric force bipedal rat scoliosis model.Methods 60 SD rats were divided into 3 groups:bipedal rat group,tether-bipedal rat group and parathyroid hormone(PTH) group.Bipedal rat model was made by amputation of the forelimbs and tail.The left inferior angle of scapula to the ipslateral bony pelvis was sutured in tether-bipedal rat group after amputation of the forelimbs and tail.Subcutaneous injection of PTH(20 μg/kg·d) was performed in PTH group.After 8 weeks,the tethering suture was released.Spinal deformity was documented with serial X-ray examinations,and the spinal Bone Mineral Density(BMD) in vivo were measured by serial dual X-ray absorptiometry(DXA) scan at an interval of 4 weeks.After sacrifice,the rotation angle of apical vertebrae was measured and Micro CT was used to analyze the bone micro-architecture.Results All rats in tether-bipedal rat group and PTH group developed scoliosis,and no scoliosis was detected in bipedal rat group.In tether-bipedal rat group and PTH group,the average Cobb angle progressed gradually after the operation and the Cobb angle in PTH group was significantly smaller than the same period tether-bipedal rat.The rotation angle of apical vertebral in PTH group was significantly reduced too.The spinal BMD in vivo increased with age in all groups(P<0.05).Compared to that in bipedal rat group and tether-bipedal rat group,the spinal BMD increased significantly(P<0.05).There was no difference in vBMD,BV/TV、Tb.Th,Tb.N,Tb.Sp between both side of vertebrae in bipedal rat group.The vBMD,BV/TV and Tb.Th on the concave side significantly increased,and Tb.Sp significantly decreased compared with that on the convex side in tether-bipedal rat group.The vBMD,BV/TV and Tb.Th on the concave side and vBMD on the convex side in tether-bipedal rat group significantly increased compared with the bipedal rat group.After the injection of PTH,the vBMD,BV/TV,Tb.Th and Tb.Sp on both sides were significantly improved,and the discrepancy between two sides were significantly reduced,compared to that in tether-bipedal rat group.Conclusion The application of PTH improved the bone remodeling level,BMD and bone microstructures,which can help to prevent the progress of scoliosis.That provided a new sight for the treatment of scoliosis.
[1]Fadzan M,Bettany-Saltikov J.Etiological theories of adolescent idiopathic scoliosis:Past and present[J].Open Orthop J,2017(11):1466-1489.
[2]Braun JT,Hoffman M,Akyuz E,et al.Mechanical modulation of vertebral growth in the fusionless treatment of progressive scoliosis in an experimental model[J].Spine,2006,31(12):1314-1320.
[3]Huynh AM,Aubin CE,Rajwani T,et al.Pedicle growth asymmetry as a cause of adolescent idiopathic scoliosis:a biomechanical study[J].Eur Spine J,2007,16(4):523-529.
[4]Lu Lingyun,Dai Zhehao,Lv Guohua,et al.A novel therapeutic strategy for adolescent idiopathic scoliosis based on osteoporotic concept[J].Med Hypotheses,2013,80(6):773-775.
[5]赵菁,虞锡丹,徐纯鑫,等.青少年特发性脊柱侧凸的国内外治疗现状[J].南通大学学报(医学版),2018,38(3):203-205.
[6]Machida M,Dubousset J,Yamada T,et al.Serum melatonin levels in adolescent idiopathic scoliosis prediction and prevention for curve progression——a prospective study[J].J Pineal Res,2009,46(3):344-348.
[7]Maria S,Witt-Enderby PA.Melatonin effects on bone:potential use for the prevention and treatment for osteopenia,osteoporosis,and periodontal disease and for use in bone-grafting procedures[J].J Pineal Res,2014,56(2):115-125.
[8]戚德胜,戴哲浩,吕国华,等.青少年特发性脊柱侧凸与骨密度[J].中国骨质疏松杂志,2014,20(5):589-591.
[9]Uchiyama T,Tanizawa T,Muramatsu H,et al.Three-dimensional microstructural analysis of human trabecular bone in relation to its mechanical properties[J].Bone,1999,25(4):487-491.
[10]Liu Y,Levack AE,Marty E,et al.Anabolic agents:what is beyond osteoporosis?[J].Osteoporos Int,2018,29(5):1009-1022.
[11]Wein MN,Kronenberg HM.Regulation of bone remodeling by parathyroid hormone[J].Cold Spring Harb Perspect Med,2018,8(8):a031237.