Methods: Thirty-two Wistar albino rats were randomly divided into four equal groups (n=8). In the control group, blood and lung samples were taken after anesthesia. In the contusion group, samples were taken 24 hours after the lung contusion. In the sildenafil groups, single doses of 1 or 5 mg/kg intraperitoneal sildenafil were given to the rats after lung contusion. Cytokines and oxidative stress parameters were studied in the specimens.

Results: In lung tissue, all parameters were significantly higher in the contusion group than in the control group (p<0.05). Sildenafil administration at the doses of 1 and 5 mg/kg significantly decreased the catalase and superoxide dismutase levels in the lung tissue with contusion (p<0.05). There was no significant difference between anti-oxidative effects of groups (p>0.05). In serum, all parameters were significantly higher in the contusion group than those of the control group (p<0.05). The sildenafil dose of 1 mg/kg significantly decreased the catalase, superoxide dismutase, and malonedialdehyde levels in the contusion group (p<0.05). The sildenafil dose of 5 mg/kg significantly improved all parameters in the contusion group (p<0.05). There was no significance difference between the sildenafil doses regarding the antiinflammatory and antioxidative effects (p>0.05).

Conclusion: Sildenafil has a corrective effect on some inflammatory and oxidative stress parameters in the rat model of lung contusion. Although, a single dose of 5 mg/kg sildenafil administration improved more parameters than a 1 mg/kg administration, the difference between the doses was not significant.