Immunomodulatory Effects and Protection in Sepsis by the Antibiotic Moxifloxacin

Abstract

Sepsis is a leading cause of death in Intensive Care Units. Despite its prevalence, sepsis remains insufficiently understood, with no substantial qualitative improvements in its treatment in the past decades. Immunomodulatory agents may hold promise, given the significance of TNF-α and IL-1β as sepsis mediators. This study examines the immunomodulatory effects of moxifloxacin, a fluoroquinolone utilized in clinical practice. THP1 cells were treated in vitro with either PBS or moxifloxacin and subsequently challenged with lipopolysaccharide (LPS) or E. coli. C57BL/6 mice received intraperitoneal injections of LPS or underwent cecal ligation and puncture (CLP), followed by treatment with PBS, moxifloxacin, meropenem or epirubicin. Atm^-/- mice underwent CLP and were treated with either PBS or moxifloxacin. Cytokine and organ lesion markers were quantified via ELISA, colony-forming units were assessed from mouse blood samples, and DNA damage was evaluated using a comet assay. Moxifloxacin inhibits the secretion of TNF-α and IL-1β in THP1 cells stimulated with LPS or E. coli. Intraperitoneal administration of moxifloxacin significantly increased the survival rate of mice with severe sepsis by 80% (p < 0.001), significantly reducing the plasma levels of cytokines and organ lesion markers. Notably, moxifloxacin exhibited no DNA damage in the comet assay, and Atm^-/- mice were similarly protected following CLP, boasting an overall survival rate of 60% compared to their PBS-treated counterparts (p = 0.003). Moxifloxacin is an immunomodulatory agent, reducing TNF-α and IL-1β levels in immune cells stimulated with LPS and E. coli. Furthermore, moxifloxacin is also protective in an animal model of sepsis, leading to a significant reduction in cytokines and organ lesion markers. These effects appear unrelated to its antimicrobial activity or induction of DNA damage.

Keywords: IL-1β; TNF-α; antibiotics; moxifloxacin; quinolones; sepsis.

Figure 1

Moxifloxacin inhibits the secretion of IL-1β and TNF-α. THP-1 cells were incubated with Escherichia coli (A,B) or lipopolysaccharide (LPS) (C,D), with moxifloxacin at concentrations of 5, 10 and 20 μM. IL-1β and TNF-α were reduced with both the stimuli. ns: non-significant; *: p < 0.05; **: p < 0.01.

Figure 2

Moxifloxacin protection against sepsis. (A) Survival of C57BL/6 WT mice subjected to CLP treated with carrier (PBS), epirubicin (0.6 μg/g body weight) or moxifloxacin (20 μg/g body weight), at time of procedure and 24 h later. (B) Survival of C57BL/6 WT with LPS treated with PBS or moxifloxacin (20 μg/g body weight). (C) Survival of ATM-KO mice subjected to CLP treated with carrier (PBS) or moxifloxacin (20 μg/g body weight) at time of procedure and 24 h later. ns: non-significant; *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001.

Figure 3

Moxifloxacin has anti-inflammatory and protective effects in vivo. Moxifloxacin reduces inflammation and tissue lesions associated with CLP, as assessed by the reduced plasma levels of TNFα (A), IL1β (B), IL6 (C), and LDH (E), ALT (F) and urea (G) in C57BL/6 WT animals 24 h after CLP followed by treatment with PBS (C + P), epirubicin (C + E), moxifloxacin (C + MX) or meropenem (C + MP). Lactate levels were not changed between all groups (H). Polymicrobial load (CFU) in blood (D) of C57BL/6 WT animals 24 h after CLP followed by treatment with PBS (C + P), moxifloxacin (C + MX) or meropenem (C + MP). ns: non-significant; *: p < 0.05; **: p < 0.01; ***: p < 0.001.

Figure 4

DNA damage in THP-1 cells treated with moxifloxacin and etoposide. Comet assay performed on THP-1 cells verified that DNA damage is similar in all groups incubated with PBS (A), E. coli (B), and with moxifloxacin (4 h), at 5 (C), 10 (D) and 20 (E) μM following stimulation with E. coli. On the other hand, treatment with etoposide (F) resulted in increased average of DNA in tail, representing high DNA damage.