Septic shock has an unacceptably high mortality rate and unmet need for new therapeutics. Murine models are crucial for research, yet methodologies often differ. This study characterised standard- and high-grade caecal ligation and puncture (CLP) murine models of septic shock by integrating ultraminiature arterial telemetry with comprehensive plasma biomarker analysis. Standard-grade and high-grade CLP was performed in 8–10 week old, male C57BL/6 mice (n = 98), with a subset implanted with arterial telemetry to monitor real-time circulatory function. Plasma markers of inflammation and organ damage were measured at multiple intervals up to 168 h post-CLP. Standard-grade and high-grade CLP showed distinct progressions; episodes of hypotension began 5–6 h after CLP in 30% of standard-grade and all high-grade CLP mice, with respective 168 h mortality of 40% and 71%. Recurrent episodes of hypotension 5–39 h after CLP were universally lethal. The coincidence of hypotension and elevated plasma lactate defined the onset of septic shock after high-grade CLP, which was always lethal. Inflammatory cytokines and markers of liver, renal, and cardiac damage were markedly elevated to 168 h after high-grade CLP, in contrast to standard-grade CLP, which returned to baseline by 48 h. Elevated plasma IL-6, TNFα, and corticosterone, along with reduced albumin, were significantly correlated with mortality. In conclusion, this research refines murine CLP models by providing a precise, dynamic map of the progression to septic shock. The high-grade CLP model consistently models early and late-stage physiological deterioration and serves as a robust model for evaluating the efficacy of novel therapies aimed at human septic shock.
Ramsay et al. (Mon,) studied this question.