Cardiac Function Evaluation in LPS-Treated Mice

We assessed cardiac function at 6 h after LPS treatment as described previously [21 (link),22 (link)]. Briefly, mice were anesthetized with pentobarbital sodium (Vortech Pharmaceuticals, Dearborn, MI, USA; 50 mg/kg, intraperitoneal (ip)) and anticoagulated with heparin (Elkins-Sinn, Cherry Hill, NJ, USA; 1,000 units/kg, ip). Animals were laid supine on a heating blanket and core body temperature was maintained at 37°C ± 0.5°C. A microcatheter (Millar Instruments, Houston, TX, USA; 1 F) was inserted into the left ventricle (LV) through the right common carotid artery. Pressure-volume loop was recorded using the MPVS-400 system with the aid of PVAN software (Millar Instruments). Heart rates, LV pressure, LV volume, and related function parameters were analyzed: 10 μL of 30% saline was injected into the inferior vena cava for actual ventricle volume calculation.