Is decreased bone mineral density associated with development of scoliosis? A bipedal osteopenic rat model

Scoliosis

Emre Acaroglu²  Ralph Marcucio¹  Nadir Yalcin¹  Gokhan Demirkiran³  Ibrahim Akel⁴  Ozgur Dede³ 

[1] University of California San Francisco, San Francisco General Hospital, Department of Orthopedic Surgery, San Francisco, CA, USA;Ankara Spine Center, Kavaklidere, Ankara, Turkey;Hacettepe University Department of Orthopedics and Traumatology, Ankara, Turkey;Izmir Kent Hospital, Cigli, Izmir, Turkey

关键词: Rat model;    Heparin;    Osteoporosis;    Idiopathic Scoliosis;   

Others  :  791901
DOI  :  10.1186/1748-7161-6-24

 received in 2011-04-30, accepted in 2011-10-31,  发布年份 2011

【 摘 要 】

Background

An association between adolescent idiopathic scoliosis and osteopenia has been proposed to exist. It is still not clear whether there is such an association and if so, whether osteopenia is a causative factor or a consequence. Our previous pilot studies have suggested the presence of osteopenia in scoliotic animals. The aim of this study was to investigate the development of scoliosis in an unpinealectomized bipedal osteopenic rat model, implementing osteoporosis as a causative factor.

Methods

Fifty Sprague-Dawley rats were rendered bipedal at the 3^rd postnatal week and separated into control (25 rats) and heparin (25 rats receiving 1 IU/gr body weight/day) groups. DEXA scans after 4 weeks of heparin administration showed low bone mass in the heparin group. Anteroposterior and lateral x-rays of the surviving 42 animals (19 in heparin and 23 in control groups) were taken under anesthesia at the 40^th week to evaluate for spinal deformity. Additional histomorphometric analysis was done on spine specimens to confirm the low bone mass in heparin receiving animals. Results of the DEXA scans, histomorphometric analysis and radiological data were compared between the groups.

Results

Bone mineral densities of rats in the heparin group were significantly lower than the control group as evidenced by both the DEXA scans and histomorphometric analyses. However, the incidence of scoliosis (82% in heparin and 65% in control; p > 0.05) as well as the curve magnitudes (12.1 ± 3.8 in heparin versus 10.1 ± 4.3 degrees in control; p > 0.05) were not significantly different. Osteopenic rats were significantly less kyphotic compared to control specimens (p = 0.001).

Conclusions

This study has revealed two important findings. One is that bipedality (in the absence of pinealectomy) by itself may be a cause of scoliosis in this animal model. Further studies on animal models need to consider bipedality as an independent factor. Secondly, relative hypokyphosis in osteopenic animals may have important implications. The absence of sagittal plane analyses in previous studies makes comparison impossible, but nonetheless these findings suggest that osteopenia may be important in the development of 3D deformity in adolescent idiopathic scoliosis.

【 授权许可】

   
2011 Dede et al; licensee BioMed Central Ltd.

【 图 表 】

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