Effect of Losartan in Complete Freund's Adjuvant -Induced Arthritis in Rats

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by joint infiltration and bone damage. The aim of the present study was to evaluate the beneficial effects of losartan in adjuvant-induced arthritis (AIA). Arthritis was induced in rats by subcutaneous injection of 0.2 mL of Complete Freund's adjuvant (CFA) in the planter surface of the hind paw. Arthritic rats were allocated into three groups (n = 10), the first group (arthritis control), received 1% of tween 80, the second and the third groups received prednisolone (10 mg/kg/day; p.o) and losartan (20 mg/kg/day; p.o) respectively for two weeks. A fourth group (vehicle control) received 1% tween 80. At the end of the experiment, blood samples were collected for biochemical, oxidative stress, and hematological analysis. Histopathological and macroscopical examinations on joints were also performed. Our results revealed that losartan significantly reduced serum levels of tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6) , rheumatoid factor (RF), and erythrocytes sedimentation rate (ESR).It significantly decreased serum malondialdehyde and increased blood glutathione .Losartan exhibited significant decrease in serum level of total cholesterol (TC), triglycerides (TG) and low density lipoprotein (LDL) coupled with marked increase in high density lipoprotein (HDL).Furthermore, losartan decreased white blood cell cells (WBC's) count and increased red blood cells (RBC's) , hemoglobin (Hb) , platelets, and hematocrit (Hct) counts. These findings were further supported by histopathological and macroscopical examinations. It could be concluded that losartan was able to repress biochemical, oxidative and hematological changes associated with AIA. These effects could be attributed to anti-arthritic, hypolipidemic, antioxidant and anti-anemic properties.