Effect of blockade of nitric oxide in heart tissue levels of Renin Angiotensin System components in acute experimental Chagas disease.

Chagas disease (CD) is an important cause of cardiomyopathy in South America. The pathophysiology of CD is still a matter of debate. Renin Angiotensin System (RAS) components are clearly involved in cardiovascular diseases. RAS molecules interact with nitric oxide (NO) pathway in blood vessel and heart tissue. Thus, the aim of this study is to investigate possible changes in RAS molecules during the infection with Y strain T. cruzi and in response to acute administration of an inhibitor of the enzyme NO synthase, l-NAME. Male Holtzman rats were inoculated intraperitoneally with Y strain T. cruzi and received l-NAME or tap water from one day before the infection until 13 or 17 days post infection (dpi). Angiotensin converting enzyme 1 (ACE1) levels were significantly higher at day 17 when compared to baseline in atrium, whereas, in ventricle, ACE2 levels were significantly higher in 13 dpi when compared to baseline. In response to l-NAME treatment, atrium tissue levels of ACE1 were significantly reduced in treated animals at day 17, while Angiotensin-(1-7) concentration in atrium significantly increased in this group at the same time-point. No changes were detected in RAS components in the ventricle. ACE2 levels in Soleus muscle were significantly reduced in treated animals at day 13. In conclusion, changes in RAS molecules were detected during acute phase of T. cruzi infection and the inhibition of NO synthesis clearly interfered with expression of ACE1 and Angiotensin-(1-7) in the atrium.