BACKGROUND:Ammonia poisoning is considered to be the main hypothesis for the pathogenesis of hepatic encephalopathy.Ammonia can lead to psychiatric and cognitive behavioral disorders,although the specific pathological molecular mechanisms remain unclear.OBJECTIVE:To investigate the effects of ammonia poisoning on cognitive behavior and hippocampal neuronal synapses in mice.METHODS:Thirty-two C57BL/6J mice were randomly divided into a normal control group and an ammonium chloride group,with 16 mice in each group.Normal saline was injected intraperitoneally in the control group,and ammonium chloride(10 mmol/kg)was injected intraperitoneally in the ammonium chloride group to construct a model of ammonia poisoning,once a day.After 7 days of ammonium chloride intervention,blood samples were collected from the hearts of six mice in each group for blood ammonia concentration detection.Behavioral experiments,including the open field test,novel object recognition test,and Y-maze test,were performed to assess mental and cognitive-behavioral changes in mice.Finally,hippocampal tissues were extracted for western blot analysis to detect the expression levels of synaptophysin and postsynaptic density protein-95 in hippocampal neurons.RESULTS AND CONCLUSION:The blood ammonia concentration was significantly elevated in the ammonium chloride group compared with the control group(P＜0.05).Mice in the ammonium chloride group showed anxiety-like behavior and disinhibition phenomenon,and a significant decrease in recognition memory and working memory ability.Western blot results revealed that the expression of synaptophysin and postsynaptic density protein-95 protein in hippocampal neurons in the ammonium chloride group was lower than that in the control group(P＜0.05).To conclude,ammonia poisoning can induce hippocampal neuronal synaptic damage,leading to psychiatric and cognitive behavioral abnormalities in mice.

BACKGROUND:Ammonia poisoning is considered to be the main hypothesis for the pathogenesis of hepatic encephalopathy.Ammonia can lead to psychiatric and cognitive behavioral disorders,although the specific pathological molecular mechanisms remain unclear.OBJECTIVE:To investigate the effects of ammonia poisoning on cognitive behavior and hippocampal neuronal synapses in mice.METHODS:Thirty-two C57BL/6J mice were randomly divided into a normal control group and an ammonium chloride group,with 16 mice in each group.Normal saline was injected intraperitoneally in the control group,and ammonium chloride(10 mmol/kg)was injected intraperitoneally in the ammonium chloride group to construct a model of ammonia poisoning,once a day.After 7 days of ammonium chloride intervention,blood samples were collected from the hearts of six mice in each group for blood ammonia concentration detection.Behavioral experiments,including the open field test,novel object recognition test,and Y-maze test,were performed to assess mental and cognitive-behavioral changes in mice.Finally,hippocampal tissues were extracted for western blot analysis to detect the expression levels of synaptophysin and postsynaptic density protein-95 in hippocampal neurons.RESULTS AND CONCLUSION:The blood ammonia concentration was significantly elevated in the ammonium chloride group compared with the control group(P＜0.05).Mice in the ammonium chloride group showed anxiety-like behavior and disinhibition phenomenon,and a significant decrease in recognition memory and working memory ability.Western blot results revealed that the expression of synaptophysin and postsynaptic density protein-95 protein in hippocampal neurons in the ammonium chloride group was lower than that in the control group(P＜0.05).To conclude,ammonia poisoning can induce hippocampal neuronal synaptic damage,leading to psychiatric and cognitive behavioral abnormalities in mice.