Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada.
Cell Tissue Res. 2022 Oct;390(1):59-70. doi: 10.1007/s00441-022-03649-2. Epub 2022 Jul 6.
The annulus fibrosus (AF) and endplate (EP) are collagenous spine tissues that are frequently injured due to gradual mechanical overload. Macroscopic injuries to these tissues are typically a by-product of microdamage accumulation. Many existing histochemistry and biochemistry techniques are used to examine microdamage in the AF and EP; however, there are several limitations when used in isolation. Immunofluorescence may be sensitive to histochemical and structural damage and permits the simultaneous evaluation of multiple proteins-collagen I (COL I) and collagen II (COL II). This investigation characterized the histochemical and structural damage in initially healthy porcine spinal joints that were either unloaded (control) or loaded via biofidelic compression loading. The mean fluorescence area and mean fluorescence intensity of COL II significantly decreased (- 54.9 and - 44.8%, respectively) in the loaded AF (p ≤ 0.002), with no changes in COL I (p ≥ 0.471). In contrast, the EP displayed similar decreases in COL I and COL II fluorescence area (- 35.6 and - 37.7%, respectively) under loading conditions (p ≤ 0.027). A significant reduction (-31.1%) in mean fluorescence intensity was only observed for COL II (p = 0.043). The normalized area of pores was not altered on the endplate surface (p = 0.338), but a significant increase (+ 7.0%) in the void area was observed on the EP-subchondral bone interface (p = 0.002). Colocalization of COL I and COL II was minimal in all tissues (R < 0.34). In conclusion, the immunofluorescence analysis captured histochemical and structural damage in collagenous spine tissues, namely, the AF and EP.
纤维环（AF）和终板（EP）是胶原质脊柱组织，由于逐渐的机械过载，这些组织经常受伤。这些组织的宏观损伤通常是微损伤积累的副产品。许多现有的组织化学和生物化学技术被用于检查 AF 和 EP 中的微损伤；然而，当单独使用时，它们有几个局限性。免疫荧光可能对组织化学和结构损伤敏感，并允许同时评估多种蛋白质-胶原蛋白 I（COL I）和胶原蛋白 II（COL II）。本研究对最初健康的猪脊柱关节进行了特征描述，这些关节要么未加载（对照），要么通过生物逼真的压缩加载。在加载的 AF 中，COL II 的平均荧光面积和平均荧光强度显著降低（分别为-54.9%和-44.8%，p≤0.002），而 COL I 没有变化（p≥0.471）。相比之下，在加载条件下，EP 中 COL I 和 COL II 的荧光面积显示出相似的减少（分别为-35.6%和-37.7%，p≤0.027）。只有 COL II 的平均荧光强度显著降低（-31.1%，p=0.043）。在终板表面，孔的归一化面积没有改变（p=0.338），但在 EP-软骨下骨界面观察到空隙面积显著增加（+7.0%，p=0.002）。COL I 和 COL II 的共定位在所有组织中都很小（R<0.34）。总之，免疫荧光分析捕捉到了胶原质脊柱组织（即 AF 和 EP）的组织化学和结构损伤。
