Abstract:

Objective     To observe the effects of ⁹⁹Tc-MDP (technetium-99 conjugated with methylene diphosphonate) on adjuvant arthritis in rats, and study its anti-inflammatory mechanism. Method    The AA(adjuvant arthritis) rat model was established by intradermal injection of complete Freud′s adjuvant. Thirty male Wistar rats were divided randomly into three groups: control group, adjuvant arthritis group and ⁹⁹Tc-MDP treatment group. In treatment group,  ⁹⁹Tc-MDP （2.5mL/kg）was administered  through caudal vein on the 10th day and repeated 15 days later after arthritis was induced. Same volume normal saline was given to the other two groups under the same protocol. Then, left-right diameter of left hind ankle, arthritis index of each rat were recorded while  PGE1 and PGE2 in peripheral blood were measured by ELISA. Results    ①The leftright diameter of left hind ankle in both  control group and  ⁹⁹Tc-MDP treatment group reduced with time, but the diameter in  ⁹⁹Tc-MDP treatment group significantly reduced（P＜0.05）than that of AA group； The arthritis index of AA group and ⁹⁹Tc-MDP treatment group both decreased with time, but the index  decreased much more significantly（P＜0.05）in the latter. ②There were no significant differences among all groups on the level of PGE1（P＞0.05）,and the level of PGE2 of the AA group and  ⁹⁹Tc-MDP treatment group were notably higher than the control（P＜0.05）. The PGE2 level of control l group was much higher than that of ⁹⁹Tc-MDP treatment group（P＜0.05）. Conclusion      ⁹⁹Tc-MDP  can reduce the left-right diameter of hind ankle and arthritis index in adjuvant arthritis rats.  ⁹⁹Tc-MDP may have a certain anti-inflammatory effect on adjuvant arthritis rats.

Key words:  Technetium 99 conjugated with methylene diphosphonate; Rheumatoid arthritis; Adjuvant arthritis; Wistar rats