Effects of ss-Adrenoceptor Subtypes on Cardiac Function in Myocardial Infarction Rats Exposed to Fine Particulate Matter (PM2.5)

The pathophysiological mechanisms of heart failure (HF) stems were mainly from longstanding overactivation of the sympathetic nervous system and renin-angiotensin-aldosterone system. Recent studies highlighted the potential benefits of beta 1-adrenoceptor (beta 1-AR) blocker combined with beta 2-adrenergic receptor (beta 2-AR) agonist in patients with HF. Long-term exposure to fine particulate air pollution, such as particulate matter <= 2.5 mu m in diameter (PM2.5), has been found associated with acute myocardial infarction (AMI) which is the most common cause of congestive HF. In this study, we have investigated the effect of combined metoprolol and terbutaline on cardiac function in a rat model of AMI exposed to PM2.5. Our results demonstrated that short-term exposure to PM2.5 contributes to aggravate cardiac function in rats with myocardial infarction. The combined use of beta 1-AR blocker and beta 2-AR agonist is superior to beta 1-AR blocker alone for the treatment of AMI rats exposed to PM2.5. The combination of beta 1-AR blocker and beta 2-AR agonist may decrease the mortality of patients with myocardial infarction who have been exposed to PM2.5.