RESUMEN
BACKGROUND:With the development of modern pathological techniques, the misdiagnosis rate has been reduced remarkably, but special stains are still the most important method for pathological diagnosis. OBJECTIVE:To compare the advantages and disadvantages of different special stains used for observing the structure of human lumbar facet joints. METHODS:The specimens of facet joint cartilage at L4/5 level were collected from patients undergoing lumbar surgery, and then stained with hematoxylin-eosin, safranin O, toluidine blue, Masson, and saranin-O-fast green for structure observation. RESULTS AND CONCLUSION:The structure of the articular cartilage could be observed clearly through hematoxylin-eosin, toluidine blue, and saranin-O-fast green staining. The cartilage surface, tidemark, and subchondral bone were shown by the hematoxylin-eosin staining, with the presence of violet chondrocyte nuclei. Safranin-O-fast green staining showed the four layers of the cartilage clearly, including the shallow layer (cartilage surface), middle layer (spherical cells arranged in disorder), columnar cell layer (large and multinucleated chondrocytes arranged neatly), tidemark, subchondral bone layer; and the cartilage matrix was reddish uniformly, the subchondral bone was green, and the cartilage and bone tissue showed a striking contrast. The cartilage structure was unclear in toluidine blue staining, with clear nuclei and almost no coloring cytoplasm, but the matrix appeared with slight purplish blue. Safranin O staining showed that the cartilage was red, which had no obvious boundary with the cartilage matrix, and chondrocytes were stained lightly. Masson staining showed clear collagen fibers, but the structures of the cartilage and subchondral were obscure. To conclude, safranin-O-fast green staining can achieve the best results, followed by hematoxylin-eosin staining and Masson staining in turn.