Liver Pathology in Mice in Poisoning by the Blue-Green Alga Microcystis Aeruginosa

Abstract

The bloom-forming M. acruginosa contains a peptide hepatotoxin. Injection of algal extracts or of solutions of purified toxin (5 x LDlOo approx.) into mice was shown to cause an increase in liver weight of 63 � 11 % within 45 min due to an increase in blood content of the organ. At the same time aspartate amino transferase and lactate dehydrogenase increased 50-fold and 20-fold respectively in serum collected by cardiac puncture. Histologically the toxin caused extensive haemorrhage in the liver with initial perilobular distribution. This was accompanied by necrosis of hepatocytes. Scanning electron microscopy showed progressive disruption of tissue structure, accumulation of erythrocytes, and loss of sinusoidal endothelium in the liver. Transmission electron microscopy confirmed that the toxin caused the breakdown of the sinusoidal endothelium and it also caused the disappearance of the space of Disse between hepatocytes and sinusoids, damage to hepatocyte membranes and necrotic changes in hepatocyte cytoplasm.