Silymarin alleviates bleomycin-induced pulmonary toxicity and lipid peroxidation in mice

Context: The application of bleomycin is limited due to its side effects including lung toxicity. Silymarin is a flavonoid complex isolated from milk thistle [Silybum marianum L. (Asteraceae)] which has been identified as an antioxidant and anti-inflammatory compound.

Objective: This study evaluates the effect of silymarin on oxidative and inflammatory parameters in the lungs of mice exposed to bleomycin.

Materials and methods: BALB/c mice were divided into four groups of control, bleomycin (1.5?U/kg), bleomycin plus silymarin (50 and 100?mg/kg). After bleomycin administration, mice received 10?d intraperitoneal silymarin treatment. On 10th day, blood and lung samples were collected for measurement of oxidative and inflammatory factors.

Results: Silymarin led to a decrease in lung lipid peroxidation (0.19 and 0.17?nmol/mg protein) in bleomycin-injected animals. Glutathione-S-transferase (GST) which was inhibited by bleomycin (32.4?nmol/min/mg protein) induced by higher dose of silymarin (41?nmol/min/mg protein). Silymarin caused an elevation in glutathione (GSH): 2.6 and 3.1?µmol/g lung compare with bleomycin-injected animals 1.8?µmol/g lung. Catalase (CAT) was increased due to high dose of silymarin (65.7?µmol/min/ml protein) compare with bleomycin treated-mice. Myeloperoxidase (MPO) which was induced due to bleomycin (p?p?Conclusions: Silymarin attenuated bleomycin induced-pulmonary toxicity. This protective effect may be due to the ability of silymarin in keeping oxidant–antioxidant balance and regulating of inflammatory mediator release.