P: 24 Comparative Morphological Analysis of Astroglia Reactivity in the Hippocampus of Rats With Acute and Chronic Hepatic Encephalopathy

Abstract

BACKGROUND: Hepatic encephalopathy (HE) is a serious complication of advanced liver failure which represents the whole neuropsychiatric abnormalities resulting from liver disease ranging from abnormal behavior to coma. Impairment of cognitive function is well described in HE patients, while mechanisms of memory impairment in HE patients is still not fully understood, however, it may involve a possible gliopathy as well as neuropathy in various brain areas, including the hippocampus known as the main brain structure associated to the memorization process. The aim of the present investigation is to assess astroglia reaction of the hippocampus, in a comparative approach between acute and chronic HE in rat. METHODS: Sprague-Dawley rats were divided into 3 groups: controls; rats were treated with saline solution (NaCl 0.9 % i.p) during 3 days, chronic HE group: rats were subjected to Bile Duct Ligation and acute HE group; rats were subjected to 3 i.p injections of thioacetamide (TAA) 300 mg/kg BW. Astroglia was assessed through an immunohistochemical analysis using anti-GFAP antibody on frontal sections of the hippocampus following. RESULTS: Our data showed in the TAA rats (3 days following 3 TAA injections) compared to controls, a significant increase of GFAP immunoreactivity within the whole hippocampal areas, while astrocytic processes length and ramification were reduced, the GFAP-immunoreactive area was increased. In contrast to BDL rats, at the cirrhotic stage (4 weeks after surgery), showing the opposite tendency with a drop of the astrocytic GFAP-immunoreactive area as well as the astrocytic length and ramification levels. CONCLUSIONS: The present finding sustains a differential astroglial reactivity within the hippocampus of acute and chronic HE rats. Astrocytic morphology changes depends to the severity of liver failure and seems to HE type-dependent, while those astroglial changes lead to a severe gliopathy which may be behind the disturbed cognitive function, especially memory seen in patients with chronic as well as acute HE.