Background: Despite advances in our understanding of excessive alcohol-intake-related tissue injury and modernization of the management of septic patients, high morbidity and mortality caused by infectious diseases in alcohol abusers remain a prominent challenge. Our previous studies have shown that milk fat globule epidermal growth factor-factor VIII (MFG-E8), a protein required to opsonize apoptotic cells for phagocytosis, is protective in inflammation. However, it remains unknown whether MFG-E8 ameliorates sepsis-induced apoptosis and organ injury in alcohol-intoxicated rats. The purpose of this study was to determine whether recombinant murine MFG-E8 (rmMFG-E8) attenuates organ injury after acute alcohol exposure and subsequent sepsis.
Methods: Acute alcohol intoxication was induced in male adult rats by a bolus injection of intravenous alcohol at 1.75 g/kg BW, followed by an intravenous infusion of 300 mg/kg BW/h of alcohol for 10 hours. Sepsis was induced at the end of 10-hour alcohol infusion by cecal ligation and puncture (CLP). rmMFG-E8 or vehicle (normal saline) was administered intravenously 3 times (i.e., at the beginning of alcohol injection, the beginning of CLP, and 10 hours post-CLP) at a dose of 20 microg/kg BW each. Blood and tissue samples were collected 20 hours after CLP in alcoholic animals for various measurements.
Results: Acute alcohol exposure per se did not affect the production of MFG-E8; however, it primed the animal and enhanced sepsis-induced MFG-E8 downregulation in the spleen. Administration of rmMFG-E8 reduces alcohol/sepsis-induced apoptosis in the spleen, lungs, and liver. In addition, administration of rmMFG-E8 after alcohol exposure and subsequent sepsis decreases circulating levels of TNF-alpha and interleukin-6 and attenuates organ injury.
Conclusions: rmMFG-E8 attenuates sepsis-induced apoptosis and organ injury in alcohol-intoxicated rats.