A Comparison of the Histochemical and Image-Derived Proteoglycan Content of Articular Cartilage

Abstract

There are several methods for determining the proteoglycan content of cartilage in biomechanics experiments. Many of these include assay-based methods and the histochemistry or spectrophotometry protocol where quantification is biochemically determined. More recently a method based on extracting data to quantify proteoglycan content has emerged using the image processing algorithms, e.g., in ImageJ, to process histological micrographs, with advantages including time saving and low cost. However, it is unknown whether or not this image analysis method produces results that are comparable to those obtained from the biochemical methodology. This paper compares the results of a well-established chemical method to those obtained using image analysis to determine the proteoglycan content of visually normal (n=33) and their progressively degraded counterparts with the protocols. The results reveal a strong linear relationship with a regression coefficient (R 2 ) = 0.9928, leading to the conclusion that the image analysis methodology is a viable alternative to the spectrophotometry.

­­­­­Insulin‐Like Growth Factor II (IGF‐II) Inhibits IL‐1β‐Induced Cartilage Matrix Loss and Promotes Cartilage Integrity in Experimental Osteoarthritis

“…Cartilage destruction was evaluated by using the OARSI scoring system and by analyzing percentage loss of Safranin O staining and chondrocyte cell loss at the articular surface [Glasson et al, ]. The software ImageJ (NIH) was used to delineate areas of cartilage and Safranin O staining loss [Singh S, ]. Chondrocyte cell density (cellularity) was determined by quantifying the total number of cells per unit area based on the Hematoxylin and Fast green staining results.…”

Characterization of Articular Cartilage Recovery and Its Correlation with Optical Response in the Near-Infrared Spectral Range

“…40,41 This was followed by absorbance profiling under monochromatic light source using a Nikon Labo-Phot light microscope to obtain micrographic images of each section before and after staining. A validated image analysis approach 43 was employed to determine the approximate PG content using custom-written program in ImageJ (version 1.45d, Wayne Rasband, National Institute of Health, Bethesda, MD). This was calculated as the area under the Safranin-O absorbance-depth profile, which shows the PG concentration and distribution.…”

“…This was calculated as the area under the Safranin-O absorbance-depth profile, which shows the PG concentration and distribution. 43…”