Intrahepatocellular erythrocyte inclusions and increased calcium precipitation in canine endotoxic shock

AIMS: To investigate the electron microscopic localization of membrane-bound and exchangeable calcium with specific calcium precipitation techniques during endotoxic shock in the dog. METHODS: Ten pentobarbital anesthetized, mechanically ventilated, and paralyzed dogs were studied. Six dogs received 2 mg/kg E. coli endotoxin i.v. followed by a continuous 0.9% saline infusion to restore and maintain baseline cardiac filling pressures. Four dogs served as time-matched controls. Each experiment lasted for 3 h. After the completion of study, the livers of four endotoxic and two control dogs were fixed by perfusion of 3% glutaraldehyde via the portal vein. Liver sections were then prepared for electron microscopy and calcium localization studies. RESULTS: Hepatocytes of endotoxic animals completely lost their plasma membrane-bound calcium. The most severely damaged cells showed extensive "blebbing" of the plasma membrane and contained numerous cytoplasmic erythrocyte inclusions. Endotoxin administration also caused excessive calcium precipitation inside hepatocytes in areas with pronounced sinusoidal damage. CONCLUSIONS: In this acute model of fluid-resuscitated endotoxic shock in dogs, the use of specific calcium localization techniques enables the demonstration of disturbances in hepatocellular calcium handling, which appear to be closely related to structural alterations of the hepatocyte cell membrane. Erythrocyte uptake by hepatocytes is a previously undescribed phenomenon in canine endotoxic shock and may serve as an additional histologic marker of ultrastructural cell (membrane) damage.