To examine hyaluronic acid (HA) dynamics in synovia with rheumatoid arthritis (RA), relying on a new quantitative technique introduced into histochemistry.
Synovial lesions from 28 patients were classified into four histologic stages of RA according to the degree of inflammation. The distribution of HA was histochemically investigated with a hyaluronic acid binding protein (HABP) and that of HA-producing cells enzyme histochemically with the expression of uridine diphosphoglucose dehydrogenase (UDPGD) activity in the synovium of RA patients. The results were quantified using an image processor for analytical pathology. The positive area of HABP reaction, the number of UDPGD-positive cells and the color density of the enzyme-histochemistry of UDPGD activity were measured with the IPAP system.
HA was shown to be diffusely distributed in the synovia, particularly densely in the superficial layer, and the distribution overlapped with that of UDPGD activation. HA distribution and UDPGD activity varied with the severity of synovial inflammation, and the positive area was the most extensive in the early stage, while it completely disappeared in the fibrotic stage.
We assume that for HA, not only does the production decrease, but the range of distribution contracts with time.