This experimental study was car­ried to evaluate the possible thera­peutic effects of amlodipine on colla­gen-induced arthritis in rats. Collagen arthritis were induced in a sprague dawley rats by intradermal injection of total volume of 0.1 ml of cold emul­sion consisting of native type II colla­gen and complete freund's adjuvant with a second immunization was giv­en after 21 days. Rats were divided into two main groups: group A, re­ceived 0.5 ml saline solution and served as normal control, group B, ar­thritic group, this group was subdivid­ed into two equal subgroups each compromised 10 rats as follows, group I, arthritic control which treated with saline and group 2 amlodipine treated arthritic group (50 ug/kg). For all groups, drugs were given as a sin­gle daily intramuscular injection for 18 days next day after the second immunization. Paws were examined mac-roscopically for redness, swelling and deformities. The severity of arthritis was evaluated by histopathological scoring of the knee joints and bio­chemically by measuring serum lev­els of TNF-a, IL-lp, nitric oxide and serum maiondialdehyde. It was found that administration of amlodipine sig­nificantly suppressed the progression of arthritis and decreased the produc­tion of TNF-ct. IL- ip, nitric oxide as well as maiondialdehyde levels in the serum.
In conclusion, these findings indi­cate that administration of amlodipine may have significant therapeutic ef­fect on the rat model of rheumatoid arthritis which was probably due to antioxidant effect and inhibition of pro-inflammatory cytokines as well as nitric oxide production.