Cardiac vulnerability during sexual maturation. Role of nitric oxide.

LA PADULA, P.; BONAZZOLA, P.; CZERNICZYNIEC, A.; VANASCO, V.; LORES ARNAIZ S.; COSTA, L.E.

Buenos Aires

Congreso; IV International Congress in Translational Medicine; 2018

Facultad de Farmacia y Bioquímica, UBA

In previous studies, upregulation of NOS during acclimatization of rats to sustained hypobaric hypoxia was associated to cardioprotection, evaluated as an increased tolerance of myocardium to hypoxia/reoxygenation (H/R). This effect started to be shown only after several weeks of chronic hypoxia. However, in a recent work we showed that 48 h of exposure to hypobaric hypoxia conferred cardioprotection mediated by the nitric oxide system in 3 month-old rats. Because chronic hypoxia had been initiated in seven-week-old rats, in the present work we evaluated the effect of acute exposure of animals to 4400 m simulated altitude on the functional capacity of NOS in the response of cardiac contractility to H/R. Sexually immature male rats were submitted to 58.7 kPa for 48 h (HH) in a hypopressure chamber and their controls remained at 101.3 kPa (C). Mechanical left ventricle pressure (LVP) and energetic performance (Ht) of hearts perfused by Langendorff technique and exposed to H/R were evaluated. Results showed that LVP was similar in HH and C hearts, but Ht tended to be higher in HH than in C (12.2 ± 1.1 vs. 10.0 ± 0.4 mW/g). After H/R, LVP increased similarly in both groups (60%), whereas Ht was 8.6 ± 0.5 vs. 10.9 ± 0.7 mW/g (p