RESUMO
Background: To evaluate the effectiveness of Nigella sativa (NS) in the prevention of hepatotoxicity of large doses of methotrexate (MTX) (IP) in rabbits. Methods: Three groups of male rabbits, six in each were used. Oral dosing was administered as a paste; formula 1 was prepared by mixing 2 g fl our with water; formula 2 contained fl our and NS and water. Group 1 was fed with formula 1 daily and injected with 2 ml/kg normal saline IP. Group 2 was given formula 1 daily with 20 mg/kg MTX IP. Group 3 was fed with formula 2 daily + MTX 20 mg/kg IP. Injections were given weekly for 5 weeks, and then the animals were sacrifi ced at day 39. Liver enzymes, malondialdehyde (MDA), glutathione (GSH), and histopathology of the liver were evaluated. Results: Liver enzymes, serum, and liver MDA were signifi cantly increased by MTX. MTX + NS treatment signifi cantly reduced the rise in liver enzymes, MDA in serum with little effect on liver MDA. Serum aspartate aminotransferase, alkaline phosphatase, and bilirubin were reduced from 82.8±18.04 U/L, 4.9±2.0 kind and king unit/100 ml and 0.74±0.1 mg/dl to 56.1±7.5, 2.0±0.6 and 0.27±0.1 respectively. Unexpectedly, serum and liver GSH were slightly increased by MTX. Treatment with MTX + NS further increased these levels. Histologically, portal and lobular sinusoidal dilatation, lymphocytic infi ltration, and hepatocyte hydropic degeneration were seen in all rabbits on MTX, which disappeared in three rabbits on NS + MTX. Conclusion: NS is hepatoprotective against MTX induced hepatotoxicity.