Sepsis is an uncontrolled systemic inflammatory response against an infection and a major public health issue worldwide. This condition affects several organs, and kidneys are particularly damaged when it is caused by Gram-negative bacteria. Due to the importance of renin-angiotensin system (RAS) in regulating renal function, in the present study, we aimed to investigate the effects of endotoxemia over the renal RAS. Wistar rats were injected with E. coli lipopolysaccharide (LPS) (4 mg/kg), mimicking the endotoxemia induced by Gram-negative bacteria. Three days after treatment, body mass, blood pressure and plasma nitric oxide (NO) were reduced, indicating that endotoxemia triggered cardiovascular and metabolic consequences and that hypotension was maintained by NO-independent mechanisms. Regarding the effects in renal tissue, inducible NO synthase (iNOS) was diminished, but no changes in the renal level of NO was detected. RAS was also highly affected by endotoxemia, since renin, Angiotensin-Converting Enzyme (ACE) and ACE2 presented decreased activity in renal tissue. Although these enzymes were modulated, only Angiotensin (Ang) II was augmented in kidneys, Ang I and Ang 1-7 levels were not influenced by LPS. Cathepsin G and chymase activities were increased in the endotoxemia group, suggesting alternative pathways for Ang II formation. Taken together, our data suggests the activation of non-canonical pathways for Ang II production and the presence of renal vasoconstriction and tissue damage in our animal model. In summary, the systemic administration of LPS affects renal RAS, what may contribute for several deleterious effects of endotoxemia over kidneys.
- Renin-Angiotensin System
- Acute Kidney Injury
- Copyright © 2014, American Journal of Physiology - Renal Physiology