Abstract:

BACKGROUND: Extensive research has been made concerning articular cartilage by domestic and foreign scholars. Different staining methods are needed to analyze the results of the research, but there was less research applying various staining methods to cartilage research or exploring staining mechanism.
OBJECTIVE: To explore the advantages and disadvantages of rat knee joint with different staining methods.
METHODS: Articular cartilage of the normal rat knee joint was sampled. The structure of normal cartilage was observed through the histological staining of hematoxylin-eosin, safranin O, alcian blue, toluidine blue, safranin-alcian blue, as well as safranin-fast green.
RESULTS AND CONCLUSION: Tidemarks with blue, red and blue colors could be observed in hematoxylin-eosin, safranin O and toluidine blue staining, respectively. The stain intensity of Safranin O and toluidine blue staining were increased toward tidemark. Thus, Safranin O staining was superior to other methods in observing tidemark. The four-layer structures of cartilage were exhibited clearly, with arranged chondrocytes columnar and basophilic matrix in hematoxylin-eosin staining. The safranin O staining showed that the four-layer structure of cartilage was clear, and the matrix at bottom was stained redder than other places. Alcian blue staining showed that, peripheral chondrocytes were strong stained at pH1.0, which stained deeper at PH2.5. The cartilage structure was not clearly in toluidine blue staining, with clearly nuclei and almost no coloring cytoplasm, but matrix was stained light blue purple. Safranirn-alcian blue staining showed that the cartilage surface and matrix exhibited different red, which was deep red at the bottom zones, but the surrounding of chondrocytes was stained blue. There was obviously contrast between cartilage tissue and bone tissue in safranin O staining, which showed red in the former and green in the latter. The results demonstrated that the 4-layer structure of cartilage can be observed by all above methods, especially safranin O staining, which is excellent in observing cartilage layers and tidemark structures. Hematoxylin-eosin staining provides better outcomes than other methods in observing morphologic changes of chondrocyte.