Department of Orthopaedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan.
Eur Spine J. 2022 Apr;31(4):874-881. doi: 10.1007/s00586-022-07148-4. Epub 2022 Feb 27.
Vertebral endplate lesion (EPL) caused by severe disc degeneration is associated with low back pain. However, there is no suitable animal model to elucidate the pathophysiology of EPL. This study aimed to develop a rat model of EPL and evaluate rat behavior and imaging and histological findings.
The L4-5 intervertebral discs of Sprague-Dawley rats were transperitoneally removed, except for the outer annulus fibrosus and cartilage endplate, in the EPL group. The L4-5 discs were not removed and simply exposed in the sham group. Changes around the vertebral endplate on magnetic resonance imaging (MRI) and computed tomography (CT) were evaluated. Additionally, pain-related behavioral and histological assessments were performed.
In the EPL group, a low-signal area around the vertebral endplate was observed on T1-weighted and T2-weighted fat-saturated MRI at 8 weeks or later after surgery. In the same group, CT showed osteosclerosis around the vertebral endplate at 12 weeks after surgery. The sham group did not show abnormal imaging features on the MRI and CT. Behavioral evaluation showed that the EPL group had a significantly longer grooming time than the sham group. Conversely, the 12-week postoperative locomotion time and the 1- and 12-week postoperative standing times were significantly shorter in the EPL group than in the sham group. Histological evaluation showed a high degree of vertebral endplate degeneration and an increased number of osteoclasts and proportion of nerve fibers expressing calcitonin gene-related peptide in the EPL group compared to those in the sham group.
Our rat EPL model showed pain-related behavioral patterns and an increased expression of pain-related neuropeptide. This model could contribute to the study of the pathophysiology of EPL and will help in the treatment of low back pain in the future.
严重椎间盘退变引起的椎体终板损伤（EPL）与下腰痛有关。然而，目前尚无合适的动物模型来阐明 EPL 的病理生理学。本研究旨在建立大鼠 EPL 模型，并评估大鼠行为、影像学和组织学发现。
EPL 组大鼠经腹腔切除 L4-5 椎间盘，仅保留外纤维环和软骨终板。假手术组大鼠 L4-5 椎间盘不切除，仅暴露。评估磁共振成像（MRI）和计算机断层扫描（CT）上椎体终板周围的变化。此外，还进行了与疼痛相关的行为和组织学评估。
EPL 组大鼠术后 8 周或以上时，T1 加权和 T2 加权脂肪饱和 MRI 上可见椎体终板周围低信号区。在同一组中，CT 显示术后 12 周时椎体终板周围有骨硬化。假手术组 MRI 和 CT 均未见异常影像学特征。行为学评估显示，EPL 组大鼠的梳理时间明显长于假手术组。相反，EPL 组术后 12 周的运动时间和术后 1 周和 12 周的站立时间明显短于假手术组。组织学评估显示，EPL 组与假手术组相比，椎体终板退变程度较高，破骨细胞数量增加，降钙素基因相关肽表达的神经纤维比例增加。
我们的大鼠 EPL 模型表现出与疼痛相关的行为模式和疼痛相关神经肽的表达增加。该模型有助于研究 EPL 的病理生理学，并有助于未来治疗下腰痛。
