Title : Long term memory deterioration associated with hippocampal microglia activation in chronic hepatic encephalopathy
Abstract:
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome resulting from impaired liver function. There is wide range of neuropsychiatric disturbances following HE, ranging from minimal alteration in the personality to the complex changes in the brain function leading to impairment in the intellect, cognition and motor activity among others. Under cirrhosis condition, more than 80% of patients can develop HE known as mild HE (MHE). MHE patients have no recognizable clinical symptoms, but when sophisticated neuropsychological and neurophysiological tests are applied a plenty of neurological and cognitive abnormalities are found. Indeed, learning and memory impairment is among the complaints of MHE patients. Several pathophysiological mechanisms are thought to underlie memory deterioration in HE. However, the exact mechanism remains undetermined. Microglia activation and the subsequent neuroinflammation might be responsible for memory abnormalities observed in HE patients. The aim of the present investigation is to assess long term memory (LTM) and identify microglial changes in chronic model of HE (CHE). The study was carried out in male Wistar rats with chronic liver failure induced by thioacetamide (TAA. 100mg/kg. b.w) administration. LTM function was assessed by Morris water maze test (MWM), together with an immunofluorescence study of the microglia activation marker; ionized calcium-binding adapter molecule 1 (Iba-1) within the hippocampal subfield; the dentate gyrus (DG). Our data showed impaired LTM in our CHE rats with significant elevation of microglia activation in the DG region of the hippocampus which might be responsible for such cognitive impairment. Hence, microglia activation and the subsequent neuroinflammation might underlie memory deterioration in HE patients.
Key words: Hepatic encephalopathy, long term memory, memory impairment, hippocampus, Morris water maze, microglia activation.
Audience Take Away:
• Hepatic encephalopathy (HE): definition, pathogenesis, etiology and classification
• Memory impairment in HE
• Long-term memory assessment in rat with chronic HE using Morris water maze test.
• We will discus our results regarding microglia activation in the hippocampus as a potential mechanism underlying memory impairment in HE.
