Association between tissue gamma-glutamyl-transferase and clinical markers of adjuvant arthritis in Lewis rats.

Objectives: To assess glucomannan and pyridoindole derivatives for possible antioxidant therapy of rheumatoid arthritis (RA) by using the model of adjuvant arthritis (AA). We evaluated the association between clinical markers of the adjuvant arthritis model used - increase of hind paw volume (HPV), changes of body mass (CBM), and tissue gamma-glutamyl transferase (GGT) activity assessed in the spleen and the joint.

Methods: AA was induced in Lewis rats by a single intradermal injection of Mycobacterium butyricum. The two independent experiments included healthy animals as reference, arthritic animals without any drug administration and arthritic animals with pyridoindole administration in one dose tested or glucomannan administration in two different doses. The pyridoindoles (PI) studied were stobadine dipalmitate and its derivatives SMe1.2HCl and SMe1EC2.HCl. We monitored CBM and HPV twice a week. Parameter of inflammation - GGT in the spleen and the joint from the hind paw (cartilage and soft tissue without bone) was determined on day 28. The correlation coefficient of GGT activity with CBM and with HPV was calculated.

Results: The antioxidants tested were effective in slowing down the progress of adjuvant arhritis. The association between tissue GGT activity and the clinical marker of adjuvant arthritis - CBM was higher in the spleen than in the joint. The other clinical marker assessed - HPV, gave a better association with GGT activity measured in the joint than in the spleen.

Conclusions: It may be concluded that GGT activity in tissues as the spleen and the joint could provide a simple and inexpensive marker for AA and RA development at systemic as well as local level; all the antioxidants studied were effective in slowing down the progress of adjuvant arhritis.