0169 : Effects of intermittent hypoxia on rat ophthalmic artery reactivity: role of endothelin 1, oxidative stress and endothelium derived hyperpolarizing factors

Obstructive sleep apnea (OSA) is a common disease, characterized by recurrent desaturation-reoxygenation sequences. Intermittent hypoxia (IH) has been proposed as major component of OSA. OSA has been recently associated with a higher frequency of optic neuropathies. There are currently no pathophysiological data regarding the effect of HI or OSA on ocular vascular system. This study aims to characterize IH impact on rat ophthalmic artery (OA) reactivity. Particularly, the role of endothelin 1 (ET-1), oxidative stress and endothelium derived hyperpolarizing factors (EDHF) were studied. Rats were exposed to 14 days IH (IH rats) or normoxia (NX rats). Ophthalmic artery reactivity was studied using wire myography. Endothelin A receptor (ETRA) expression and superoxide anions production in OA were studied by immunohistolabelling and DHE labelling respectively. After 14 days IH, ETRA immunolabeling and superoxide anions expression in OA were increased by 22% (p = 0.015) and 23% (p = 0.04) respectively in IH rats. Ophthalmic artery contraction to 3.10-8 M ET-1 was increased by 16% (p The author hereby declares no conflict of interest