Semevolos Stacy A, Brower-Toland Brent D, Bent Stephen J, Nixon Alan J
Comparative Orthopaedics Laboratory, College of Veterinary Medicine, Cornell University, C3-187 Veterinary Medical Ctr, Ithaca, NY 14853, USA.
J Orthop Res. 2002 Nov;20(6):1290-7. doi: 10.1016/S0736-0266(02)00055-4.
Early changes in parathyroid hormone-related peptide (PTH-rP) and Indian hedgehog (Ihh) expression were examined in equine articular osteochondrosis (OC) as a model of a naturally acquired dyschondroplasia. Cartilage was harvested from OC-affected femoropatellar or scapulohumeral joints from immature horses and normal control horses of similar age. PTH-rP expression levels were assessed by semi-quantitative PCR, in situ hybridization, and immunohistochemistry. Ihh protein expression levels were assessed by immunohistochemistry. Elevated PTH-rP protein and mRNA expression were identified in the deeper layers of affected articular cartilage and the fibrous tissue of interposing clefts. These changes were confined to the chondrocytes in the OC-affected cartilage, which had significantly increased PTH-rP protein and mRNA expression when compared to control cartilages. Ihh protein expression showed similar distribution as PTH-rP in the deeper layers of articular cartilage; however, only a trend for increased Ihh immunostaining was evident in the OC cartilage when compared to the normal cartilage. Increased PTH-rP expression in prehypertrophic chondrocytes of diseased OC cartilage suggests a possible link between this peptide and the delayed ossification, which is a consistent histologic alteration in OC. More evidence is necessary to determine the role of Ihh in articular cartilage and if a similar feedback cycle exists as previously described for the growth plate.
作为一种自然发生的软骨发育异常模型，研究了马关节骨软骨病（OC）中甲状旁腺激素相关肽（PTH-rP）和印度刺猬因子（Ihh）表达的早期变化。从未成熟马以及年龄相仿的正常对照马的患OC的股髌关节或肩胛肱关节采集软骨。通过半定量PCR、原位杂交和免疫组织化学评估PTH-rP表达水平。通过免疫组织化学评估Ihh蛋白表达水平。在受影响关节软骨的深层以及中间裂隙的纤维组织中发现PTH-rP蛋白和mRNA表达升高。这些变化局限于患OC的软骨中的软骨细胞，与对照软骨相比，这些软骨细胞的PTH-rP蛋白和mRNA表达显著增加。Ihh蛋白表达在关节软骨深层与PTH-rP表现出相似的分布；然而，与正常软骨相比，在OC软骨中仅明显有Ihh免疫染色增加的趋势。患病OC软骨的前肥大软骨细胞中PTH-rP表达增加表明该肽与延迟骨化之间可能存在联系，延迟骨化是OC中一致的组织学改变。需要更多证据来确定Ihh在关节软骨中的作用以及是否存在如先前所述生长板那样的类似反馈循环。
