No abstract

Pulmonary arterial hypertension (PAH) is characterized by enhanced pulmonary vascular resistance with subsequent remodeling and right ventricular hypertrophy. Vascular reactivity and ventricular function were investigated in rats with monocrotaline-induced PAH and treated with a new N-acylhydrazone derivative named as LASSBio-1359. METHODS: Protocols were approved by Animal Care and Use Committee at Universidade Federal do Rio de Janeiro. Male Wistar rats received a single i.p. injection of monocrotaline (MCT) (60 mg/kg) for PAH induction and were randomly divided in groups which were treated with: saline, vehicle and LASSBio-1359 (50 mg/kg p.o.). After 14 days of treatment, some parameters were evaluated: pulmonary acceleration time (PAT); right ventricular systolic pressure (RVSP); vascular reactivity to acetylcholine; expression of iNOS in pulmonary tissue; wall thickness of pulmonary artery (PAWT). Results: PAT (ms) was increased from 26.2 ± 2.8 to 41.3 ± 3.9 in PAH group treated with vehicle (n=8, p<0.05) and was reduced to 24.2 ± 1.7 when PAH group was treated with LASSBio-1359. RVSP (mmHg) increased from 26.0 ± 2.0 to 55.2 ± 2.3 in PAH group (p<0.05) but was similar to control after treatment with LASSBio-1359 (31.8 ± 2.3 mm Hg). Ratio of right ventricle and body weight (mg/g) was 0.66 ± 0.02, 1.63 ± 0.16 and 0.87 ± 0.10 for control, vehicle- and LASSBio-1359-treated PAH groups, respectively. PAH promoted ventricular dysfunction which was reduced by LASSBio-1359. The pulmonary artery maximum relaxation (%) was 57.3 ± 5.5, 43.6 ± 1.2 and 61.4 ± 8.4 for control, vehicle and LASSBio-1359-treated groups indicating that PAH promoted endothelium injury which was recovered by LASSBio-1359. iNOS expression in pulmonary tissue was increased from 0.48 ± 1.31 to 0.98 ± 3.14 in PAH group and reduced to 0.53 ± 1.83 in rats treated with LASSBio-1359. The PAWT (%) were increased from 74.1 ± 1.3 to 90.2 ± 2.7 in PAH group (p<0.05) but was 74.4 ± 1.3 when treated with LASSBio-1359. This compound showed an in vitro vasodilatory activity mediated by activation of adenosinergic A2A receptor. Conclusion: LASSBio-1359 reduced ventricular and vascular dysfunction in monocrotaline-induced PAH in rats indicating a possible new alternative to treat PAH.