Cell patterns in the surface of rabbit articular cartilage revealed by the backscatter mode of scanning electron microscopy.

To study the distribution of cells in the surface layer of articular cartilage, rabbit hip and knee specimens were stained with silver and studied by scanning electron microscopy (SEM). The cartilage was treated en bloc using the Gomori methenamine silver technique, which stains the nuclei of exposed cells with reduced silver. The intact surface was then studied with a binocular microscope and SEM in the backscatter mode Only those cells within 30 microns of the surface stained, permitting that population to be imaged selectively. Depressions in the surface were related to groups of cells in clusters or rows bounded by collagen fibers. This study demonstrates the effectiveness of backscatter imaging in the study of chondrocytes. The relationship between surface contours and underlying cells is more complex than previously described.