Objective: To investigate the protective effects of silymarin (SIL) against the damage caused by methotrexate (MTX) in rat liver tissue.

Materials and Methods: A total of 36 adult Sprague-Dawley male rats were divided into 6 groups with 6 animals each: Group I received 0.5 mL intraperitoneal (ip) saline solution, Group II received carboxymethyl cellulose (CMC) orally, Group 3 received SIL 300 mg / kg dissolved in CMC orally, Group IV received a single dose of 20 mg/kg (ip) MTX, Group V received a single dose of 20 mg/kg (ip) MTX + oral CMC, and Group VI received a single dose of MTX 20 mg/kg (ip) + SIL 300 mg/kg dissolved in CMC orally. The experiment was administered over a period of 5 days. At the end of the experiment, rat liver tissues were removed and routine histological procedures were performed.

Results: The liver tissues in Groups I, II, and III were similar in terms of histopathologic and immunohistochemical findings. In groups IV and V, histopathological findings were similar and vascular congestion, sinusoidal dilatation, and inflammatory cell infiltration were observed. In the same groups, the intensity of TUNEL, Bax and Caspase 3 positive cells was increased compared to those of other experimental groups. In group VI, tissue damage decreased significantly.

Conclusion: MTX resulted in significant tissue damage in the liver tissue and SIL ameliorated this damage.