Therapeutic Dose of Zinc Aspartate and Zinc Citrate Attenuates Disease Activity Indices in Rheumatoid Arthritis

Zinc aspartate and zinc citrate have been used as zinc supplements in different health conditions. Taking into consideration their anti-inflammatory, immunomodulatory, anti-oxidant and antimicrobial properties, the present study has been designed to analyse the effect of zinc aspartate and zinc citrate treatment at therapeutic dose level on disease severity index, haematological, serological, antimicrobial and radiological markers of rheumatoid arthritis in Wistar rats. Bactericidal potential of the two organic zinc compounds was analysed in vitro in clinically isolated Escherichia coli. Arthritis was induced in male Wistar rats by intradermal injection of an emulsion containing collagen type II and Complete Freund's Adjuvant (CFA) containing 1 mg mL^-1 Mycobacterium tuberculosis H37Ra. Zinc aspartate and zinc citrate were orally administered after the onset of the disease for 4 weeks. Ameliorative effect of zinc aspartate and zinc citrate was evaluated by analysing indices of severity and disease activity markers of rheumatoid arthritis. The liver and kidney function tests were performed to evaluate any possible adverse effect of compounds. Antimicrobial activity of the zinc compounds was assessed in clinically isolated E. coli by MTT assay. Zinc aspartate and zinc citrate equivalent to a therapeutic dose of 50 mg/day of elemental zinc attenuated the clinical characteristic of rheumatoid arthritis in the animal model of arthritis, collagen-induced arthritis (CIA). Both zinc salts also exhibited antimicrobial effects against E. coli. The selected dose of zinc aspartate and zinc citrate showed no adverse effects in treated rats. This study highlights the potentiality of zinc compounds as antiarthritic agents and also point to its preventive effects on microbial growth that has been observed in rheumatoid arthritis patients due to their increased sensitivity for bacterial infection.