ABSTRACT
Hepatic encephalopathy (HE) represents a brain dysfunction caused by both acute and chronic liver failures, and its severity deeply affects the prognosis of patients with impaired liver function. In its pathophysiology, ammonia levels and glutamatergic system hyperactivity seem to play a pivotal role in the disruption of brain homeostasis. Here, we investigate important outcomes involved in behavioral performance, electroencephalographic patterns, and neurochemical parameters to better characterize the well-accepted animal model of acute liver failure (ALF) induced by subtotal hepatectomy (92% removal of tissue) that produces ALF. This study was divided into three cohorts: (1) rats clinically monitored after hepatectomy every 6â¯h for 96â¯h or until death; (2) rats tested in an open-field task (OFT) before and after surgery and had blood, cerebrospinal fluid, and brain tissue collected after the last OFT; and (3) rats that had continuous EEGs recorded before and after surgery for 3â¯days. The hepatectomized rats presented significant motor behavioral changes accompanied by important abnormalities in classical blood laboratory parameters of ALF, and EEG features suggestive of HE and deep disturbances in the brain glutamatergic system. Using an animal model of ALF induced via subtotal hepatectomy, this work provides a comprehensive and reliable experimental model that increases the opportunity for studying the effects of new treatment strategies to be explored in an unprecedented way. It also presents insights into the pathophysiology of HE in a reproducible model of ALF, which correlates important neurochemical and EEG aspects of the syndrome.
Subject(s)
Brain/physiopathology , Exploratory Behavior , Hepatic Encephalopathy/physiopathology , Liver Failure, Acute/physiopathology , Animals , Disease Models, Animal , Electroencephalography , Hepatectomy , Hepatic Encephalopathy/blood , Liver Failure, Acute/blood , Male , Motor Activity/physiology , Nervous System Malformations , Rats , Rats, WistarABSTRACT
Neste trabalho foi feita a caracterização citogenética da: microsporogênese, tétrades, estimativa da viabilidade do pólen pelo método de coloração e contagem do número máximo de nucléolos por célula interfásica, para identificação dos níveis de ploidia, em cinco espécies do gênero Mentha L. Foram coletadas inflorescências em 30 plantas de cada espécie, em duas florações sucessivas, nos anos 2006 e 2007. As inflorescências foram tratadas em etanol-ácido acético (3:1), em temperatura ambiente durante seis horas, transferidas para álcool 70% (v/v) e conservadas em geladeira até análise. Nas análises da microsporogênese, tétrades e pólen o corante usado foi carmin propiônico 2% e na identificação dos nucléolos nitrato de prata (AgNO3). Os resultados demonstraram que as cinco espécies são poliplóides. M. crispa heptaplóide (2n=7x=84) com 11 nucléolos, M. spicata tetraplóide (2n=4x=48) com 8 nucléolos, M.x gentilis pentaplóide (2n=5x=60) com 12 nucleólos, M. piperita e M.x piperita ambas hexaplóides (2n=6x=72) com 8 e 9 nucléolos respectivamente. M. spicata e M. crispa mantiveram as mais altas porcentagens de células normais na microsporogênese, na formação de tétrades e na estimativa da viabilidade do pólen por coloração, sugerindo maior estabilidade meiótica quando comparados aos demais poliplóides estudados.
The cytogenetic characterization of five species of Mentha L. genus, including the data: regularity of microsporogenesis and tetrads, and polen viability, using the coloration method and the counting of the maximum number of nucleolus by interphasic cell were carried out in this study to identify the ploid levels. These analyses were performed from inflorescences collected in 30 plants of each species, during two successive florations in 2006 and 2007. Inflorescences were treated in 3:1 ethanol:acetic acid mixture at room temperature during six hours, then transferred to 70%(v/v) ethanol solution and refrigerated until the analysis. For microsporogenis, tetrad and pollen analysis, we used carmine propionic 2% (m/v) and for nucleolus identification, we used AgNO3 solution. It was possible to observe that all five species were polyploids. M. crispa heptaploid (2n=7x=84) with 11 nucleolus, M. spicata tetraploid (2n=4x=48) with 8 nucleolus, M. x gentilis pentaploid (2n=5x=60) with 12 nucleolus, M. piperita and M. x piperita both hexaploid (2n=6x=72) with 8 and 9 nucleolus respectively. M. spicata and M. crispa kept the highest percentual values of normal cells in microsporogenesis as well as in tetrads formation and pollen viability, suggesting a higher meiotic stability when compared to the other polyploids studied.
