Murine model to study brain, behavior and immunity during hepatic encephalopathy

Abstract

AIM:To propose an alternative model of hepatic encephalopathy (HE) in mice, resembling the human features of the disease. METHODS:Mice received two consecutive intraperitoneal injections of thioacetamide (TAA) at low dosage (300 mg/kg). Liver injury was assessed by serum transaminase levels (ALT) and liver histology (hematoxylin and eosin). Neutrophil infiltration was estimated by confocal liver intravital microscopy. Coagulopathy was evaluated using prolonged prothrombin and partial thromboplastin time. Hemodynamic parameters were measured through tail cuff. Ammonia levels were quantified in serum and brain samples. Electroencephalography (EEG) and psychomotor activity score were performed to show brain function. Brain edema was evaluated using magnetic resonance imaging. RESULTS:Mice submitted to the TAA regime developed massive liver injury, as shown by elevation of serum ALT levels and a high degree of liver necrosis. An intense hepatic neutrophil accumulation occurred in response to TAA-induced liver injury. This led to mice mortality and weight loss, which was associated with severe coagulopathy. Furthermore, TAA-treated mice presented with increased serum and cerebral levels of ammonia, in parallel with alterations in EEG spectrum and discrete brain edema, as shown by magnetic resonance imaging. In agreement with this, neuropsychomotor abnormalities ensued 36 h after TAA, fulfilling several HE features observed in humans. In this context of liver injury and neurological dysfunction, we observed lung inflammation and alterations in blood pressure and heart rate that were indicative of multiple organ dysfunction syndrome. Key words: Hepatic encephalopathy; Liver injury; Thioacetamide; Neurological dysfunction; Neuropsychomotor abnormalities; Intracranial hypertension; Cerebral herniation Core tip: The study of hepatic encephalopathy is crucial for development of new therapies but has been dampened by the absence of murine models resembling the disease in patients. We showed that sequential thioacetamide injections cause extensive liver injury in mice, leading to increased ammonia levels, electroencephalography alterations and brain edema. In line with this, mice presented with poor psychomotor activity and survival rate. Liver injury and brain function impairment by thioacetamide resulted in systemic alterations such as coagulopathy, hemodynamic instability and lung inflammation, consistent with multiple organ failure. Therefore, this alternative model may provide tools for new therapeutic insights for hepatic encephalopathy. CONCLUSION:Gomides LF, Marques PE, Faleiros BE, Pereira RV, Amaral SS, Lage TR, Resende GHS, Guidine PAM, Foureaux G, Ribeiro FM, Martins FP, Fontes MAP, Ferreira AJ, Russo RC, Teixeira MM, Moraes MF, Teixeira AL, Menezes GB. Murine model to study brain, behavior and immunity during hepatic encephalopathy. World J Hepatol 2014; 6(4): 243-250 Available from: URL:

Effects of early or late prenatal immune activation in mice on behavioral and neuroanatomical abnormalities relevant to schizophrenia in the adulthood

“…The imaging protocol consisted of coronal T2-weighted (TR = 3000 ms, TE = 50 ms) spin echo multislice scans, 16 contiguous 1 mm thick slices ( Fig. 6D − 9 sequential brain images), in accordance with previous literature (Gomides et al, 2014). Mice (n = 24) were anesthetized with halothane (4% induction, 1.5% maintenance) together with oxygen (1.5 l/min), and the total imaging time was about 50 min per mouse, time required to obtain the images.…”

Understanding liver immunology using intravital microscopy

“…Methodologically, DILI can be acutely induced by administration of a high dose of different chemicals, including acetaminophen (APAP) [18,21,23], thioacetamide (TAA) [51], carbon tetrachloride (CCl 4 ) [52], ethanol [53], halothane [54], alphaamanitin [55] and others. Due to the vast available literature about DILI, here we will focus on APAP and Concanavalin-A induced liver injury.…”

“…It is conventionally evaluated using histology; however, recent studies proposed strategies to visualize and quantify liver necrosis in vivo by intravenous administration of DNA-binding probes (Sytox green, propidium iodide or DAPI). These dyes bind to DNA deposited within necrotic areas, being very useful for intravital assessment of cell death [18,51].…”

Research progress on hepatic encephalopathy: animal models and disease mechanisms

“…In addition, after TAA treatment, the content of ammonia in serum and brain tissue of mice significantly increased, which were closely related with its pathological symptoms [including weight loss, blood clotting abnormalities, electroencephalography (EEG) changes and cerebral edema]. It suggests the rise of ammonia content in serum and brain may be an important cause of acute HE [15] . There are diverse administrations for TAA-induced HE, but no consistent dosage has been settled down.…”