Effects of olmesartan therapy on the expression of lung adrenoceptors in rats with chronic heart failure.

Introduction: Adrenergic receptors (AR) play important roles in regulating lung function. However, there are few reports concerning AR expression and the protective effect of angiotensin II receptor blockers (ARB) on the lung in chronic heart failure (CHF). In this study, we aimed to investigate the protective effects of the ARB olmesartan on the lung in CHF. Materials and methods: Wistar rats were randomly divided into four groups: normal control, sham-operated rats, rats with CHF induced by ligating the left anterior descending coronary arteries, and rats with CHF treated with olmesartan (1 mg/kg) once daily for 8 weeks. Heart function, plasma renin activity (PRA) and angiotensin II (Ang II) levels, lung microscopic structure inspection and mRNA and protein expressions of (1A)-, (1)- and (2)-AR in lung were tested. Results: Compared with the CHF group, PRA and Ang II levels were decreased while heart function and mRNA and protein expression of (1A)-AR, (1)-AR and (2)-AR were up-regulated in the olmesartan group (p<0.05 or p<0.01). The inflammation and cell proliferation in CHF lung tissue were reduced in the olmesartan group. Conclusion: Olmesartan may play a beneficial role in protecting lung in CHF by up-regulating AR and decreasing levels of PRA and Ang II.