Bratislava Medical Journal Vol.116, No.3, p.177-183, 2015

Background: We aimed to investigate the therapeutic effectiveness of leflunomide (LEF) in lung injury after an aspiration of unknown pathophysiology.
Material and methods: Forty-two healthy Sprague Dawley rats were anesthetized and allocated to six experimental groups: saline (S) aspirated, S+LEF, hydrochloric acid (HCl) aspirated, HCl+LEF, formula aspirated (FOR), and FOR+LEF. The treatment groups (S+LEF, HCl+LEF, and FOR+LEF) received 20 mg/kg/day intraperitoneal (i.p.) injection of LEF for seven days. At the end of the seven days, blood and tissue samples were taken from the rats for histopathological, biochemical, and immunohistochemical examination.
Results:

There was a significant increase in serum levels of YKL-40, a chitinase-like protein, in the HCl group after the aspiration (p<0.01).

The increase in serum YKL-40 levels decreased significantly with LEF treatment (p<0.01).

There was no significant difference in serum YKL-40 levels in the FOR group compared to the control group at pretreatment and in the FOR+LEF group at post-treatment.

There was a significant increase in serum thiobarbituric acid-reactive species (TBARS) values in the HCl and FOR groups compared to the control group (p=0.001 and p<0.01, respectively).

In both treatment groups, the serum TBARS values significantly decreased after treatment with LEF (p=0.001 and p<0.05, respectively).

There was a significant improvement in the histopathological scores, which deteriorated after the aspiration, and in the number of inducible nitric oxide synthase (iNOS)-positive cells after treatment with LEF.