Animal models
In order to reproduce hepatic encephalopathy pathology, different animal models have been developed. Among those, 2 surgical rat models encapsulate many characteristics of the illness in its chronic form.
PCA ( portocaval anastomosis )
Portocaval anastomosis is a surgical procedure by which systematic circulation is diverted from the liver. This model mimics the creation of collateral circulation during cirrhosis.
Normally, the blood coming from the intestines enters the liver via the portal vein, is detoxified and goes out through the hepatic veins to feed the body's organs. In order to remove the liver's contribution to blood circulation, the portal vein is ligated and sutured to inferior vena cava.
This model has been recognized as being similar to hepatic encephalopathy, though with some abnormalities in behavior. It ultimately leads to hyperammonemia . However, no cerebral edema or Alzheimer type 2 cells have been detected.
BDL (bile-duct ligation)
Bile-duct ligation is a surgery that destroys the liver, equivalent to a biliary cirrhosis. Bile, which is normally excreted by the bile duct, is returned to the liver. The toxicity of bile-induced cirrhosis results in the death or dysfunction of the liver cells.
Animals develop jaundice, hepatic fibrosis, portal hypertension, a variable portosystemic derivation, hyperammonemia and a dysfunction of the immune system. These models develop motor and memory difficulties.
Note: All experimental protocols and animal manipulations were approved by the Comité Institutionnel de protection des animaux (CIPA) du CHUM, leaning on the guidelines of Canadian Council on Animal Care (CCAC), and are performed by skilled persons.
Oxidative Stress
Glossary