A new hepatic encephalopathy model to monitor the change of neural amino acids and astrocytes with behaviour disorder.

Abstract

BACKGROUND/AIMS: To elucidate the pathogenesis of hepatic encephalopathy (HE), we developed a new HE model with behaviour disorder. METHODS: Male Wistar rats were divided into four treatment groups: a HE model: acetaminophen (APAP)+3-methylcholanthrene (3-MC) group (APAP+MC group); control group: acetaminophen group; 3-methylcholanthrene group; and a no-treatment group. We monitored the changes of neural amino acids in the synaptic cleft and astrocytes in the brain during behaviour disorder. RESULTS: In the APAP+MC group, alanine amino transferase, blood ammonia and glucose increased from 3 h and total bilirubin increased at 6 h. Prothrombin time was prolonged from 3 h in the APAP+MC group. The APAP+MC group exhibited centrilobular necrosis in the liver after 8 h. In the APAP+MC group, rats jumped vertically and this vertical activity increased significantly from 4 to 7 h. During the behaviour disorder, we found that glutamate and aspartate increased in the synaptic cleft from 4 h after treatment with APAP+3-MC, glutamate increased 23.9-fold at 7 h and aspartate increased 16.1-fold at 4 h, whereas glutamine did not change. At that time, we observed morphological changes of the astrocytes by immunostaining for the glial fibrillary acidic protein. CONCLUSIONS: Our new HE model demonstrated that increased excitatory neural amino acids and morphological change in astrocytes were involved in the behaviour disorder that occurs with HE.