Grissom S K, Semevolos S A, Duesterdieck-Zellmer K
Department of Clinical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, United States of America.
Bone Rep. 2023 Jan 5;18:101653. doi: 10.1016/j.bonr.2023.101653. eCollection 2023 Jun.
The objective of this study is to better understand the pathogenesis of early equine osteochondrosis (OC) by identifying differences in gene and protein expression of extracellular matrix components and regulators in normal and diseased cartilage and bone, focusing on the osteochondral junction and cells surrounding the cartilage canals. We expected to find an upregulation of matrix metalloproteinases and a decrease in extracellular matrix constituent expression along the osteochondral junction and cells surrounding the cartilage canals in OC samples. Paraffin-embedded osteochondral samples (6 OC-affected, 8 normal controls) and cDNA from chondrocytes captured with laser capture microdissection from frozen sections (4 OC-affected, 5 normal controls) were used in this study. Quantitative real-time polymerase chain reaction was performed on 16 target genes. Immunohistochemistry was performed on osteochondral samples for Sox-9, lubricin, osteocalcin, and collagen type IIB. In OC-affected samples, there was significantly ( ≤ 0.05) decreased gene expression of collagen type IIB, aggrecan, and SOX-9 in chondrocytes surrounding the cartilage canals and decreased gene expression of PRG4 (Lubricin) and collagen type IIB in chondrocytes along the osteochondral junction. We found significantly lower collagen type IIB total matrix percentages in the middle and deep cartilage layers, lower lubricin total cellular percentage in the superficial layer, and higher Sox-9 total cellular percentage in bone of OC samples. No significant differences were found in matrix degradation molecules or HSCORE protein expression at any locations between normal and OC-affected samples in our study.
本研究的目的是通过识别正常和患病软骨及骨骼中细胞外基质成分和调节因子的基因和蛋白质表达差异，更好地理解早期马骨软骨病（OC）的发病机制，重点关注骨软骨交界处和软骨管周围的细胞。我们预计在OC样本的骨软骨交界处和软骨管周围的细胞中发现基质金属蛋白酶上调，细胞外基质成分表达减少。本研究使用了石蜡包埋的骨软骨样本（6个OC患病样本，8个正常对照）以及从冰冻切片中通过激光捕获显微切割获取的软骨细胞的cDNA（4个OC患病样本，5个正常对照）。对16个靶基因进行了定量实时聚合酶链反应。对骨软骨样本进行了Sox-9、润滑蛋白、骨钙素和IIB型胶原蛋白的免疫组织化学检测。在OC患病样本中，软骨管周围的软骨细胞中IIB型胶原蛋白、聚集蛋白聚糖和SOX-9的基因表达显著降低（≤0.05），骨软骨交界处的软骨细胞中PRG4（润滑蛋白）和IIB型胶原蛋白的基因表达降低。我们发现OC样本的中层和深层软骨层中IIB型胶原蛋白的总基质百分比显著降低，表层润滑蛋白的总细胞百分比降低，骨骼中Sox-9的总细胞百分比升高。在我们的研究中，正常样本和OC患病样本之间在任何位置的基质降解分子或HSCORE蛋白表达均未发现显著差异。
