Effects of Muramyl Dipeptide and Core Body Temperature on Peritoneal Bacterial Clearance

Abstract

To examine the interaction between muramyl dipeptide (MDP) and core body temperature in murine peritonitis, 120 Sprague-Dawley rats were randomized to receive either 0, 1, or 4 micrograms/g body weight of MDP. Twenty-four hours later a sublethal intraperitoneal inoculation of Escherichia coli was given after core body temperature regulation at 32 degrees C to 40 degrees C, which was maintained for 30 minutes. Killing of the rats at 1, 3, or 6 hours later allowed evaluation of peritoneal white blood cell and bacterial counts. Results demonstrated that MDP (independent of core body temperature) caused an increased peritoneal white blood cell response at one and six hours and an increased peritoneal bacterial clearance at three hours. Increasing core body temperature adversely affected peritoneal bacterial clearance. High-dose MDP was clearly significant in acceleration of peritoneal bacterial clearance. No interaction between MDP and core body temperature was seen.