Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA.
Osteoarthritis Cartilage. 2011 Sep;19(9):1132-41. doi: 10.1016/j.joca.2011.05.008. Epub 2011 Jun 1.
Meniscus lesions following trauma or associated with osteoarthritis (OA) have been described, yet meniscus aging has not been systematically analyzed. The objectives of this study were to (1) establish standardized protocols for representative macroscopic and microscopic analysis, (2) improve existing scoring systems, and (3) apply these techniques to a large number of human menisci.
Medial and lateral menisci from 107 human knees were obtained and cut in two different planes (triangle/cross section and transverse/horizontal section as well) in three separate locations (middle portion, anterior and posterior horns). All sections included vascular and avascular regions and were graded for (1) surface integrity, (2) cellularity, (3) matrix/fiber organization and collagen alignment, and (4) Safranin-O staining intensity. The cartilage in all knee compartments was also scored.
The new macroscopic and microscopic grading systems showed high inter-reader and intra-reader intraclass correlation coefficients. The major age-related changes in menisci in joints with no or minimal OA included increased Safranin-O staining intensity, decreased cell density, the appearance of acellular zones, and evidence of mucoid degeneration with some loss of collagen fiber organization. The earliest meniscus changes occurred predominantly along the inner rim. Menisci from OA joints showed severe fibrocartilaginous separation of the matrix, extensive fraying, tears and calcification. Abnormal cell arrangements included decreased cellularity, diffuse hypercellularity along with cellular hypertrophy and abnormal cell clusters. In general, the anterior horns of both medial and lateral menisci were less affected by age and OA.
New standardized protocols and new validated grading systems allowed us to conduct a more systematic evaluation of changes in aging and OA menisci at a macroscopic and microscopic level. Several meniscus abnormalities appear to be specific to aging in the absence of significant OA. With aging the meniscal surface can be intact but abnormal matrix organization and cellularity were observed within the meniscal substance. The increased Safranin-O staining appears to represent a shift from fibroblastic to chondrocytic phenotype during aging and early degeneration.
创伤后或与骨关节炎（OA）相关的半月板损伤已有描述，但半月板老化尚未得到系统分析。本研究的目的是：（1）建立具有代表性的宏观和微观分析的标准化方案；（2）改进现有的评分系统；（3）将这些技术应用于大量的人半月板。
从 107 个人膝关节中获取内侧和外侧半月板，并在三个不同位置（中部、前角和后角）以两种不同的平面（三角形/横切和横切/水平切）进行切割。所有的切片都包括有血管和无血管区域，并对（1）表面完整性，（2）细胞密度，（3）基质/纤维组织和胶原排列，以及（4）番红 O 染色强度进行分级。所有膝关节腔的软骨也进行了评分。
新的宏观和微观分级系统显示出高的读者间和读者内的组内相关系数。在没有或仅有轻微 OA 的关节中，半月板的主要与年龄相关的变化包括番红 O 染色强度增加、细胞密度降低、出现无细胞区以及黏液样变性的证据，伴有一些胶原纤维组织的丢失。最早的半月板变化主要发生在内侧边缘。OA 关节的半月板显示出基质的严重纤维软骨分离、广泛的磨损、撕裂和钙化。异常的细胞排列包括细胞密度降低、弥漫性细胞增生以及细胞肥大和异常细胞簇。一般来说，内侧和外侧半月板的前角受年龄和 OA 的影响较小。
新的标准化方案和新的验证评分系统使我们能够在宏观和微观水平上对老化和 OA 半月板的变化进行更系统的评估。一些半月板异常似乎是在没有明显 OA 的情况下与老化有关的特异性改变。随着年龄的增长，半月板表面可能是完整的，但在半月板实质内观察到异常的基质组织和细胞密度。番红 O 染色的增加似乎代表了在老化和早期退变过程中从成纤维细胞向软骨细胞表型的转变。
