[Studies on anti-inflammatory agents. (5). Specific characteristic of bone changes in adjuvant arthritic rats with passage of time].

Adjuvant arthritic rats develop marked changes in the distal limb joints. These changes were observed by soft X-ray photography at appropriate intervals. It was confirmed that the "cotton wool appearance" surrounding the bones, which was readily discernible from the radiographs, was a good indicator for following the progression of bone damages. Standard radiographs were selected to represent the various bone changes based on the "cotton wool appearance". When the incidence rates of bone deformation confirmed on the basis of the above method were plotted against Weibull Probability Paper, the plots conformed with the Weibull distribution function. Thus, it was possible to evaluate bone changes in adjuvant arthritic rats by observing the "cotton wool appearance" surrounding the bones.