Effects of chronic intermittent hypoxia and polyunsaturated fatty acids on infarct size and oxidative stress markers in cardiac ischemia reperfusion

Abstract

Chronic intermittent hypoxia (CIH) induces structural and functional changes in heart, probably associated with ischemia-reperfusion (IR), a pathophysiological event linked with excessive reactive oxygen species generation. The cardioprotective effects of polyunsaturated fatty acids (PUFA) have not been well characterized in CIH. The aim of this study was to determine the effects of CIH and PUFA on infarct size (IS) and oxidative stress markers in cardiac IR. Twenty-eight adult rats were randomly divided in 4 groups: normobaric normoxia (Nx); Nx + PUFA (0.3 g.kg-1d-1); hypobaric hypoxia (Hx); and Hx + PUFA. CIH was induced by 4 intercalate periods of hypoxia-normoxia with 96 hours intervals each, in a hypobaric chamber (428 tor; pO2: 89.6 mmHg) during 32 days. In ex vivo model (Langendorff), hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion. The IS, TBARS, GSH/GSSG ratio and IL1beta levels were assessed in hearts. Infart size decreased in 25.8% (Nx+PUFA), 3