Angiotensin-(1-7) attenuates organ injury and mortality in rats with polymicrobial sepsis

Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP).

Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination.

Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05).

In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.