Relation Of MGluR1 With Hepatic Encephalopathy And The Study Of Effect Of MGluR1 Antagonist

Objective To observe expression of mGluR1a,the changes of cell appearance and intracellular free calcium in astrocytes and neurons induced by ammonia and glutamate in vitro;comparison mGluR1a expression in rat brain of acute liver failure with the control group.To investigate the possible therapeutical effect of LY367385--a mGluR1a antagonist,therefore,explore the relationship between mGluR1a and hepatic encephalopathy,provide the theory basis for further research of new medicine to treat hepatic encephalopathy and brain edema.Methods Observe the changes of mGluR1a expression in astrocytes and neurons induced by ammonia and glutamate in vitro,the morphology and ultra microstructure of cells were observed by inverted phase contrast microscope and transmission electron microscope.Flow Cytometer(FCM)was used to count apoptosis and necrosis cells,calcium fluorescent indictor Flluo-3/Am was used to detect the variation of calcium in astrocytes and neurons.As well as the change of above-mentioned subject were observed by added LY367385.Acute liver failure models were induced by thioacetamide(TAA)on rats.assay arterial plasma ammonia by automatic biochemistry analyzer,the morphology and substructure of brain cells were observed by hematoxylin-eosin stain and transmission electron microscope,the change of mGluR1a expression in brain were observed by immunohistochemistry stain and quantified by a computerized image analyzer.5ul of LY367385 or NS were microinjected into lateral ventricles of Acute liver failure rats respectively,measuring brain water content at 24 hour later,the morphology and substructure of brain cells were observed by hematoxylin-eosin stain and transmission electron microscope. Results mGluR1a were expressioned in astrocytes and neurons,especially in neurons,ammonia and glutamate can induce astrocytes and neurons apoptosis and necrosis,in addition ammonia and glutamate can increase the level of intracellular free calcium and lead to LDH releasing.LY367385 can decreasing apoptosis and necrosis induced by ammonia and glutamate,reducing cell LDH leak out,decrease the concentration of calcium.Acute liver failure model were made successfully. Compared with control group,the acute liver failure rats were present serve hepatic encephalopathy and accompanied obviously brain edema,furthermore,mGluR1a expression were upgraded in this group.LY367385 microinjected into lateral ventricles of liver failure rats can reduce swelling of astrocytes and neurons,and decrease of brain water content in some degree.Conclusion ammonia and glutamate can induce astrocytes and neurons apoptosis and necrosis,strength the concentration of calcium and lead to LDH releasing Correlation with the activation of mGluR1a,LY367385 can blocking mGluR1a and downgrade calcium,concentration, decrease apoptosis and necrosis of astrocytes and neurons induced by ammonia and glutamate,thioacetamide(TAA)can induce Acute liver failure,the acute liver failure rats were present serve hepatic encephalopathy and accompanied obviously brain edema,LY367385 can lower grade of hepatic encephalopathy and alleviate brain edema in some extent.Its necessary to research new medicine to block mGluR1, provide new therapy to hepatic encephalopathy and brain edema.