Purpose: Background and Objective:
Tacrolimus is a macrolide calcineurin inhibitor isolated from Streptomyces tsukubaensis and is clinically used as an immunosuppressive agent in the transplant patients. Tacrolimus has also been shown to suppress inflammation and has been approved for rheumatoid arthritis in various countries like Canada, Europe, USA etc. Emblica officinalis also known as Phyllanthus emblica and Amla is a small to medium sized deciduous tree belonging to family Euphorbiaceae. Fruits have been used for thousands of years in the traditional Indian medicine for the treatment of several diseases. The fruits has been claimed to have anti-inflammatory and antioxidant properties. So, the present study was carried out to investigate the effects of Emblica officinalis fruit extract (EOE) in combination with Tacrolimus (TAC) on joints swelling, stiffness score and arthritic index, production various cytokines and nuclear factor-κB (NF- κB) activation in rats with complete adjuvant-induced arthritis (CFA).
Methods: Arthritis was induced in rats by a single injection of 0.1 ml of Complete Freund’s adjuvant into the subplantar surface of left hind paw of rat. Rats were treated with TAC (3 mg/kg) daily and combination of TAC and EOE (200 mg/kg) daily for a period of 21 days. The changes in Joint swelling, arthritis index, stiffness score, macroscopical, histopathological, immunohistochemical and radiographic analysis was assessed to evaluate the antiarthritic effect of TAC in combination with EOE. Lipid peroxidation and antioxidant enzyme activities in joint tissue homogenate were performed to observe the modulation of antioxidant status along the expression of different pro-inflammatory cartilage cytokines like IL-1, IL-6, TNF-R1, VEGF and NF-κB. Level of TNF-α was also assessed using enzyme-linked immunosorbent assay.
Results: The combination of TAC and EOE significantly (p<0.001) decreases joint diameter stiffness score and arthritic index of hind paw on day 21, as compared to CFA injected rats as shown in Figure 1 (a & b). Significant decrease (p<0.001) in levels of lipid peroxidation (MDA), serum TNF-alpha and increase in antioxidant (GSH, SOD) levels were noted in combination group as shown in Figure 1 (c ). Moreover, macroscopical, histopathological and radiographical examination demonstrated that combination of TAC and EOE significantly reduced the synovial hyperplasia and denudation of inflammatory cells in joints tissues as shown in Figure 2. Combination of TAC and EOE significantly ameliorates the expression of various pro-inflammatory cytokines, as evaluated immunohistochemically in Figure 3.
Conclusion: TAC significantly attenuates arthritis and inflammation development throughout the model, however, TAC at higher doses possess significant adverse effects such as nephrotoxicity. We had evaluated the combinatory effect of TAC with EOE so as to reduce the dose dependent side effects, in which EOE significantly alleviates rheumatoid arthritis and reduces side effects owing to decline in levels of oxidative markers. Therefore, EOE can serve as a useful adjuvant in combination with tacrolimus and promote the safe use of tacrolimus in Rheumatoid arthritis.
Surender Singh– AIIMS, New delhi