Purpose: NO and NO synthase (NOS) are known to play key roles in the development of myocardial apoptosis induced by ischemia/hypoxia. Current evidence suggests that angiotensin II type 1 receptor blockers, such as telmisartan, lower blood pressure and produce beneficial regulatory effects on NO and NOS. Here, we examined the protective role of telmisartan in myocardial apoptosis induced by chronic intermittent hypoxia (CIH).
Methods: Adult male Sprague-Dawley rats were subjected to 8 h of intermittent hypoxia/day, with/without telmisartan for 8 weeks. Myocardial apoptosis, NO and NOS activity, and levels of inflammatory mediators and radical oxygen species were determined.
Results: Treatment with telmisartan preserved endothelial NOS expression and inhibited inducible NOS and excessive NO generation, while reducing oxidation/nitration stress and inflammatory responses. Administration of telmisartan before CIH significantly ameliorated the CIH-induced myocardial apoptosis.
Conclusions: This study show that pre-CIH telmisartan administration ameliorated myocardial injury following CIH by attenuating CIH-induced myocardial apoptosis via regulation of NOS activity and inhibition of excessive NO generation, oxidation/nitration stress, and inflammatory responses.