Peyman Mohammadzadeh - Department of Pathobiology, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran

METHOD:Totally 20 male rabbits were fed adaptively for 14 days and then divided into the normal control group, the MCT group, the MCT +lin (85 mg x kg(-0.5)) group andthe MCT + lin (150 mg x kg(-0.5)) group, with 5 rabbits in each group. The PH rat model was induced through the subcutaneous injection with MCT(80 mg x kg(-0.5)).After the administration for three weeks, efforts were made to measure the right ventricular systolic pressure( RVSP) and mean pulmonary artery pressure (mPAP) through right jugular vein catheterization, and isolate right ventricle( RV) and left ventricle( LV) +septum (S) and measure their length to calculate RV/ ( LV + S) and ratio of RV to tibial length. Pathologic changes in arterioles were observed by HE staining. Masson s trichrome stain was used to demonstrate changes in collagen deposition of arterioles. The alpha-smooth muscle actin (alpha-SMA) expression in pulmonary arteries was measured by immunohistochemisty. The malondialdehyde (MDA) and total antioxidative capacity (T-AOC) content in pulmonary arteries were determined by the colorimetric method. The protein expressions of collagen I, NOX2 and NOX4 were analyzed by Western blot and Real-time PCR. RESULT: After the administration for3 weeks, lin could attenuate RVSP and mPAP induced by MCT, RV/ (LV + S) and ratio of RV to Tibial length, alpha-SMA and collagen I expressions and remodeling of pulmonary vessels and right ventricle. Meanwhile, lin could obviously inhibit the expressions of NOX2, NOX4 and MDA content andincrease T-AOC. CONCLUSION: Linum usitatissimum could ameliorate pulmonary vascular remodeling induced by monocrotaline in PH rabbits. Its mechanism may be related to expressions of NOX2 and NOX4 expression and reduction in oxidative stress injury.

linum usitatissimum,pulmonary,vascular remodeling,rabbit