anti-VEGF neutralizing antibody inhibits the progress of ossification of the ligament in the ossification of the spinal ligament

脚尖行走(TTW)小鼠是四肢和脊柱各种软组织异位骨化的模型。脊柱韧带的异位骨化导致脊柱的后纵韧带(OPLL)和黄色韧带(OYL)的骨化。本研究用抗血管内皮生长因子中和抗体对TTW小鼠进行了体内注射，测量了小鼠脊柱韧带骨化面积。注射抗血管内皮细胞生长因子中和抗体的TTW小鼠(V组)与注射PBS的TTW小鼠(P组)相比，脊柱韧带骨化的增加受到抑制。P组在骨化前沿可见骨钙素免疫阳性细胞和X型胶原表达，而V组仅见藏红O染色细胞，X型胶原表达较少，表明软骨细胞肥大和/或成骨细胞的诱导受到抑制，软骨细胞持续存在。提示抑制血管内皮生长因子可能抑制了脊柱韧带软骨内骨化的进程。与P组相比，V组脊髓韧带骨化区的血管侵袭受到抑制，提示应用抗血管内皮生长因子中和抗体抑制血管侵袭也可能抑制脊髓韧带的软骨内骨化。

Tiptoe Walking (ttw) mouse is a model for ectopic ossification of various soft tissues in the extremities and spine. Ectopic ossification of spinal ligaments results in ossification of the posterior longitudinal ligament (OPLL) and of the yellow ligament (OYL) of the spine. In this study, anti-VEGF neutralizing antibody was administered intraperitoneally in ttw mouse and the ossified area of the spinal ligament was measured. The increase of the ossification of the spinal ligament was inhibited in the ttw mouse, which anti-VEGF neutralizing antibody was administered (group V), compared with the control ttw mouse, which PBS was administerd (group P). Osteocalcin immunopositive cells and expression of type X collagen were observed in the ossification front of group P, whereas safranine-O staining cells was seen and expression of type X collagen were little in that of group V, which indicates that hypertrophy of the chondrocytes and/or induction of the osteoblasts are inhibited and chondrocytes are persisted. It suggests that suppression of VEGF may inhibit the course of endochondral ossification in the spinal ligament. Vascular invasion was suppressed in the ossified area of the spinal ligament in group V compared with that in group P, which suggested that inhibition of vascular invasion by administration of anti-VEGF neutralizing antibody may also suppress the endochondral ossification in the spinal ligament.