Abstract

This study was performed to investigate the effect of endotoxin to the CCl4-induced liver injury. Twelve Sprague-Dawley rats were intraperitoneally injected 1.6 g/kg CCl4 as control group. Another 24 rats were orally administrated 300 mg/kg of neomycin at 16 and 3 hours prior to CCl4 injection as experimental group. Twelve among them were intraperitoneally infected 1.0 mg/kg of endotoxin(E-Coli, 0111:B4, No L-2630, lipopolysaccharide, Sigma, USA) and CCl4 simultaneously for offsetting neomycin effect. The rats were sacrificed at 1, 4, 10, and 24 hours after CCl4 injection. The liver tissues from all experimental groups were observed by light and electron microscopy. The results obtained were summarized as follows: In the CCl4 only group, the hepatocytes revealed sweling of ER and mitochondria with many lipid droplet in the cytoplasm. Focal cellular necrosis was seen at the later phase. The Kupffer cells were activated and showed many cytoplasmic processes, secondary lysosomes, and vaculoles. The endothelial cells were edematous. Several neutrophils, platelets, and microthrombi were scattered in the sinusoid. In the neomycin-CCl4-endotoxin administrated group, both hepatocytic destruction and intrasinusoidal microthrombi formation were more pronounced. In the neomycin pretreated group, the hepatocytes revealed mild cellular destruction without necrosis. There is no intrasinusoidal microthrombi. According to these results, it would be concluded that the small dosage of gastrointestinal tract-derived endotoxin affects to the liver injury caused by CCl4. The synergistic effects of CCl4 and gastrointestinal tract-derived endotoxin which can not be detoxified by damaged Kupffer cells, may be more important in the pathogenesis of CCl4-induced liver injury.

• Keywords: CCl4;Endotoxin;Neomycin;Liver injury;