Gut-derived substances in activation of hepatic macrophages after partial hepatectomy in rats

When liver perfusion with nitro blue tetrazolium and phorbol myristate acetate was performed in rats 24 h after two-thirds liver resection, there were marked deposits of formazan converted from nitro blue tetrazolium in hepatic macrophages throughout the liver, indicating macrophage activity. The extent of the deposits was significantly reduced when perfusion was performed following oral administration of polymyxin B sulfate, a non-absorbable bacteriocidal agent against gram-negative bacilli which can also bind endotoxin lipopolysaccharides. Polymyxin B sulfate administration also attenuated the derangements of SGPT and the histological liver injury provoked by endotoxin administration after partial hepatectomy. These results suggests that gut-derived substances sensitive to polymyxin B sulfate may contribute to activation of hepatic macrophages after partial hepatectomy in rats.