The Effect of Cabergoline on the Clinical and Immunological Aspects of Rheumatoid Arthritis Induced in Wistar Rats

The anti-inflammatory effects of cabergoline have been documented in various studies. The purpose of the present study was to evaluate the effects of cabergoline administration (as a potent D2 agonist) on clinical aspects and immune responses in rheumatoid arthritis (RA) induced in Wistar rats. In the present experimental study, the population consisted of 40 male Wistar rats with a weight range of 160 to 180 g. Animals were randomly allocated into four groups of 10, including the control group (healthy), RA group treated with PBS (100 mg/kg orally), RA group treated with cabergoline (50 µg/kg-orally) and ultimately RA group treated with Prednisolone (10 mg/kg orally). Changes in severity of disease and changes in temperature were recorded every three days. All treatments were initiated at day 7, after induction and observation of the first symptoms of foot inflammation in all rats. Finally, the serum of rats was isolated to evaluate the levels of nitric oxide (Griess assay) and myeloperoxidase (evaluation of the ability to the reduction of hydrogen peroxide). Spleen cells were isolated in sterile conditions in order to evaluate the lymphocyte proliferation rate (MTT reduction assay), the intensity of the respiratory burst (NBT reduction assay), and the potential of neutral red phagocytosis. Data were analyzed using Kruskal-Wallis statistical tests and one-way ANOVA and Tukey tests. The cabergoline drug was similar to prednisolone, which led to a reduction in the severity of the disease and the swelling of soles of the feet (p=0.15). The serum levels of nitric oxide (p=0.0001) and myeloperoxidase (p=0.0001), the intensity of the respiratory burst of splenic phagocytic cells (p=0.002) and the proliferation rate of splenic lymphocytes (p=0.02) were significantly decreased in both treatment groups. Prednisolone indicated a more profound effect than cabergoline in reducing the lymphocyte proliferative index (p=0.001), while cabergoline effectively reduced respiratory burst activity (p=0.002). Moreover, cabergoline significantly revealed a more profound effect than prednisolone in reducing the increased levels of neutral red uptake by splenic phagocytic cells (p=0.01). Considering the appropriate results in the animal model, the use of cabergoline may be considered as a useful approach to control RA.