Machida Masafumi, Saito Masashi, Dubousset Jean, Yamada Thoru, Kimura Jun, Shibasaki Keiichi
Department of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
Eur Spine J. 2005 Nov;14(9):843-8. doi: 10.1007/s00586-004-0806-1. Epub 2005 Apr 30.
The pathological mechanism of curve progression in idiopathic scoliosis is still obscure. In this study we investigated the pathological mechanism of idiopathic scoliosis in experimentally induced scoliosis in rats. A total 30 rats were divided into three groups: ten bipedal rats with a sham operation, which served as the control; ten quadrupedal rats with pinealectomy; and ten bipedal rats with pinealectomy. Scoliosis developed only in pinealectomized bipedal rats and not in pinealectomized quadrupedal rats. Cervicothoracic lordosis developed in bipedal rats with or without pinealectomy. These deformities of lordoscoliosis in pinealectomized bipedal rats were similar to human idiopathic scoliosis. Lordosis or lordotic tendency was sufficient to cause the spine to rotate to the side. Rotational instability of the spine with rotation of lordotic segment appears to produce a characteristic scoliotic deformity as a secondary phenomenon. Our findings suggest that lordosis may develop in bipedal rats, but pinealectomy is required for the development of lordoscoliosis. Balanced muscle tone controlled by the postural reflex is important to maintain normal posture with a straight spine in the bipedal condition. The disturbance of equilibrium and other postural mechanisms secondary to a deficiency of melatonin after pinealectomy may promote development of lordoscoliosis with vertebral rotation especially in the bipedal posture.
特发性脊柱侧弯中曲线进展的病理机制仍不清楚。在本研究中，我们在实验诱导的大鼠脊柱侧弯中研究了特发性脊柱侧弯的病理机制。总共30只大鼠被分为三组：十只接受假手术的双足大鼠作为对照组；十只接受松果体切除的四足大鼠；以及十只接受松果体切除的双足大鼠。脊柱侧弯仅在接受松果体切除的双足大鼠中出现，而在接受松果体切除的四足大鼠中未出现。无论是否接受松果体切除，双足大鼠都会出现颈胸段前凸。接受松果体切除的双足大鼠的这些脊柱前凸侧弯畸形与人类特发性脊柱侧弯相似。脊柱前凸或脊柱前凸倾向足以使脊柱向一侧旋转。随着脊柱前凸节段的旋转，脊柱的旋转不稳定似乎会作为一种继发现象产生特征性的脊柱侧弯畸形。我们的研究结果表明，双足大鼠可能会出现脊柱前凸，但脊柱前凸侧弯的发展需要松果体切除。由姿势反射控制的平衡肌肉张力对于在双足状态下保持脊柱挺直的正常姿势很重要。松果体切除后褪黑素缺乏继发的平衡和其他姿势机制的紊乱可能会促进脊柱前凸侧弯并伴有椎体旋转的发展，尤其是在双足姿势中。
