Method of histomorphometric assessment of glycosaminoglycans in articular cartilage

A method of image analysis has been developed for use in the semiquantitative histomorphometric assessment of glycosaminoglycans in articular cartilage stained with safranin O. The reliability of the methodology is reported along with its application to the assessment of articular cartilage in a model of osteoarthritis, i.e., transection of the anterior cruciate ligament in rabbits. With this system, specimens of normal and osteoarthritic articular cartilage were assessed histomorphometrically for the following parameters: total cartilage area, percentage of safranin O stained area, mean gray scale (average stain intensity), and gray scale index (the relative total amount of glycosaminoglycans). Reproducibility was established for 12 specimens of normal cartilage and found to have a SD of less than 8% of the mean for each parameter that was measured. Image analysis of osteoarthritic cartilage revealed each of the parameters, except for average stain intensity, to be significantly lower than that in control cartilage.