Monoclonal antibody to tumor necrosis factor-alpha modulates hepatocellular Ca2+ homeostasis during hemorrhagic shock in the rat.

Tumor necrosis factor-alpha (TNF-alpha) is a key mediator of shock-induced cellular and humoral inflammatory cascades. The present study investigated the role of TNF-alpha in oxidative membrane injury and altered hepatocyte Ca2+ regulation, both of which are critical steps in cellular dysfunction during ischemia/reperfusion events. Hemorrhagic shock was induced by bleeding male Sprague-Dawley rats (200-250 g, n=6/group) to a mean arterial blood pressure of 40 mmHg for 60 min. Rats were resuscitated with 60% of shed blood and twice the shed blood volume as Ringers' lactate. At the end of hemorrhage and 60 min after resuscitation, hepatocytes were isolated by liver collagenase perfusion. Hepatocyte Ca2+ uptake (Ca2+up) and Ca2+ membrane flux (Ca2+flux) were determined by 45Ca2+ incubation techniques. Hepatocyte reduced/oxidized glutathione and lipid peroxidation were determined fluorometrically. Both hemorrhage and hemorrhage/resuscitation significantly increased hepatocyte Ca2+up and Ca2+flux. The monoclonal chimeric mouse gamma1 TNF-alpha antibody (TN3gamma1.19.12; 20 mg/kg b.w.) given with resuscitation significantly decreased hepatocyte Ca2+up and Ca2+flux and prevented hepatocyte lipid peroxidation. These findings suggest that oxidative membrane injury could be the result of TNF-alpha modulation of hepatocellular Ca2+ regulation during hemorrhage/resuscitation.