Short Report : Beneficial Effects of Benznidazole during an Infectious-based Situation of Systemic Inflammatory Response : Cecal Ligation and Puncture

We have shown that benznidazole (BZL), a drug used to treat Chagas disease, markedly reduced the production of pro-inflammatory cytokines and NO-derived metabolites in experimentally Trypanosoma cruzi–infected rats. Treatment with BZL exerted beneficial effects in a model of inflammation-based pathology like murine experimental endotoxemia. Based on these findings, we wished to ascertain the effect of BZL in a closer situation to sepsis: the cecal ligation and puncture (CLP) model in C57BL/6 mice. We analyzed clinical course, survival, circulating levels of inflammation-related compounds (NO, tumor necrosis factor [TNF]), and bacteriemia. Recipients of BZL, 25 mg/kg, had an increased survival rate at 24 hours after CLP, showing a better clinical situation and a significant reduction of TNFlevels and bacteriemia, with respect to the other groups. BZL failed to inhibit in vitro bacterial growth, suggesting that these effects may be partly caused by the immunomodulatory effects of BZL. Benznidazole (BZL) has been used for the treatment of acute Chagas’ disease for more than three decades. In addition to its trypanocidal activity, our studies indicate that BZL also affects the synthesis of important biological response modifiers with potential implications in inflammatory processes. By using different experimental approaches, it was shown that BZL downregulated NO and cytokine synthesis by lipopolysaccharide (LPS) and/or interferon (IFN)– stimulated murine macrophages. Systemic treatment with BZL in Trypanosoma cruzi–infected rats inhibited the production of pro-inflammatory cytokines and NO-derived metabolites. Beneficial effects of BZL were also seen in murine experimental endotoxemia. C57BL/6 mice given BZL orally and challenged with LPS intraperitoneally had decreased mortality, reduced serum levels of pro-inflammatory cytokines, diminished number of interleukin (IL)-6–producing peritoneal macrophages, and lowered IL-12 and inducible NO synthase (iNOS) mRNA expression in liver samples. These findings provided a stimulating background for analyzing the usefulness of BZL during infections, accompanied by a strong and ultimately detrimental inflammatory reaction. Ineffective clearance of pathogens or failure of regulatory mechanisms may result in systemic inflammation, further progressing to an aggravated situation such as septic shock. Septic shock seems to have a multifactorial basis, with tissue damage being not only caused by the presence of pathogens but also to mediators released in response to infection. Tumor necrosis factor (TNF) is a major inflammatory cytokine in this regard. Factors involved in anti-microbial mechanisms also include NO, which plays diverse biological roles (i.e., vascular tone, neurotransmission, and immune response). NO overproduction may be relevant for the development of some pathological events occurring during septic shock. Given this background, we analyzed the effect of BZL in a closer situation to sepsis, the cecal ligation and puncture (CLP) model. The CLP murine model mirrors more closely the clinical course of abdominal sepsis in humans, because it is triggered by an endogenous septic focus progressing to a polymicrobial infection with systemic inflammatory response syndrome. Male C57BL/6 mice, 8–10 weeks of age, were provided by the School of Veterinarian Sciences, National University of La Plata. Experiments were conducted according to internationally accepted guidelines for animal handling. Mice were divided into eight experimental groups: 1) sham control plus vehicle (V); 2) sham control plus treatment with BZL 10 mg/kg body weight; 3) sham control plus BZL 25 mg/kg body weight; 4) sham control plus BZL 200 mg/kg body weight; 5) CLP + V; 6) CLP + BZL 10 mg/kg body weight; 7) CLP + BZL 25 mg/kg body weight; and 8) CLP + BZL 200 mg/kg