Jian Quan-Liang, HuangFu Wei-Chun, Lee Yen-Hua, Liu I-Hsuan
Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan.
The Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
PeerJ. 2018 Oct 1;6:e5739. doi: 10.7717/peerj.5739. eCollection 2018.
Both age and intensive exercise are generally considered critical risk factors for osteoarthritis. In this work, we intend to establish zebrafish models to assess the role of these two factors on cartilage homeostasis. We designed a swimming device for zebrafish intensive exercise. The body measurements, bone mineral density (BMD) and the histology of spinal cartilages of 4- and 12-month-old zebrafish, as well the 12-month-old zebrafish before and after a 2-week exercise were compared. Our results indicate that both age and exercise affect the body length and body weight, and the micro-computed tomography reveals that both age and exercise affect the spinal BMD. However, quantitative analysis of immunohistochemistry and histochemistry indicate that short-term intensive exercise does not affect the extracellular matrix (ECM) of spinal cartilage. On the other hand, the cartilage ECM significantly grew from 4 to 12 months of age with an increase in total chondrocytes. dUTP nick end labeling staining shows that the percentages of apoptotic cells significantly increase as the zebrafish grows, whereas the BrdU labeling shows that proliferative cells dramatically decrease from 4 to 12 months of age. A 30-day chase of BrdU labeling shows some retention of labeling in cells in 4-month-old spinal cartilage but not in cartilage from 12-month-old zebrafish. Taken together, our results suggest that zebrafish chondrocytes are actively turned over, and indicate that aging is a critical factor that alters cartilage homeostasis. Zebrafish vertebral cartilage may serve as a good model to study the maturation and homeostasis of articular cartilage.
年龄和高强度运动通常都被认为是骨关节炎的关键风险因素。在这项研究中，我们打算建立斑马鱼模型来评估这两个因素对软骨稳态的作用。我们设计了一种用于斑马鱼高强度运动的游泳装置。比较了4个月和12个月大斑马鱼的身体测量数据、骨密度（BMD）以及脊柱软骨的组织学情况，还比较了12个月大的斑马鱼在进行2周运动前后的情况。我们的结果表明，年龄和运动都会影响体长和体重，微计算机断层扫描显示年龄和运动都会影响脊柱骨密度。然而，免疫组织化学和组织化学的定量分析表明，短期高强度运动不会影响脊柱软骨的细胞外基质（ECM）。另一方面，随着年龄从4个月增长到12个月，软骨ECM显著增加，软骨细胞总数也增加。脱氧尿苷三磷酸缺口末端标记染色显示，随着斑马鱼生长，凋亡细胞的百分比显著增加，而溴脱氧尿苷（BrdU）标记显示，从4个月到12个月，增殖细胞显著减少。对BrdU标记进行30天的追踪显示，4个月大的斑马鱼脊柱软骨细胞中有一些标记保留，但12个月大的斑马鱼软骨中没有。综上所述，我们的结果表明斑马鱼软骨细胞有活跃的更新，并表明衰老 是改变软骨稳态的关键因素。斑马鱼椎体软骨可能是研究关节软骨成熟和稳态的良好模型。
