Angiotensin II receptor blocker irbesartan attenuates sleep apnea-induced cardiac apoptosis and enhances cardiac survival and Sirtuin 1 upregulation.

Abstract

The purpose of this study was to investigate whether or not angiotensin II type 1 receptor blocker irbesartan (ARB) with a partial agonist of PPAR-γ could protect against chronic nocturnal intermittent hypoxia (CIH)-induced cardiac Fas/FasL-mediated to mitochondria-mediated apoptosis. Sprague-Dawley rats were in a normoxic control group (CON-G), or rats werein a chronic nocturnal intermittent hypoxia group (HP-G, from 3 to 7% oxygen versus 21% oxygen per forty seconds cycle, nocturnally 8h per day for 1month), or rats were in a chronic nocturnal intermittent hypoxia group pretreated withARB (50mg/kg/day, S.C.) (ARB-HP-G). Echocardiography, H&E staining, TUNEL staining, and Western blotting were measured inthe left ventricle. Hypoxia-induced SIRT1 degradation, Fas receptors, FADD, active caspase-8 and caspase-3 (Fas/FasL apoptotic pathway) and Bax, tBid, active caspase-9 and -3 (mitochondrial apoptotic pathway) and TUNEL-positive apoptosis were reduced in ARB-HP-G when compared with HP-G. IGF-I, IGF1 receptor, p-PI3k, p-Akt, Bcl2, and Bcl-XL (IGF1/PI3K/AKT pro-survival pathway) were increased in ARB-HP-G compared to HP-G. Our findings suggest that the ARB may prevent cardiac Fas/FasL to mitochondrial apoptotic pathways and enhance cardiac IGF1/PI3K/AKT pro-survival pathway in the sleep apnea model associated with JNK de-activation and SIRT1 upregulation. ARB prevents chronic sleep apnea-enhanced cardiac apoptosis via enhancing survival pathways.