Electrophysiology of hippocampal neurons and behavior characteristics in mouse models of intracerebral hemorrhage

Objective To establish mouse models of intracerebral hemorrhage using autologous arterial blood, to study the physiological property of hippocampal neurons, brain edema changes and learning ability in the mouse models after intracerebral hemorrhage. Methods Eighty male C57/BL6 mice were randomly divided into intracerebral hemorrhage group and control group (n=40); 20 μL arterial blood from the tail arteries or normal saline were injected into the caudate nucleus of intracerebral hemorrhage group and control group by stereotactic technique, respectively. One, three, five and seven d after injection, the neurological impairment was scored; the behavioral changes of the mice in the Morris water maze (navigation test and space exploration experiment) were observed; brain edema was measured by wet and dry weight method and electrophysiological differences of hippocampal neurons were recorded by whole-cell patch-clamp technique and computer software. Results As compared with those in the control group, significantly increased neurological deficit scores one, three, five and seven d after injection, statistically decreased residence time in the platform on the fifth d of training, obviously increased water content around the brain edema one, three, five and seven d after injection, and significantly decreased resting membrane potential and input resistance in the hippocampal CA1 pyramidal cells five d after injection of mice in the intracerebral hemorrhage group were noted (P<0.05). Conclusion The hippocampus-dependent spatial learning ability of intracerebral hemorrhage mice is decreased, and the permeability of potassium channels is enhanced. Key words: Intracerebral hemorrhage; Hippocampus; Behavioristics; Encephaledema; Electrophysiological characteristics