Abstract: ObjectiveTo explore the effects of the conjugate prepared from the cholera toxin B subunit(CB) and nerve growth factor(NGF) on the spatial learning and memory abilities and cholinergic function.MethodsThe conjugate of CB-NGF was prepared by the improved sodium metaperiodate method and nasally administrated to the β-amyloid protein(Aβ_25-35) induced amnesic mice for 7 days with 2 dosage (7-5 μg/d、15 μg/d). Spatial learning and memory abilities were evaluated by Morris water maze and cholinergic function was assessed with the choline acetyl transferase (ChAT) immunohistochemical methods.ResultsMorris water maze test showed that the escape latency in Aβ_25-35-treated mice prolonged and the staying time reduced in the crossed first quadrant where the platform had been located, compared with the control mice (P<0-01). In addition, the number of ChAT positive neuron declined in the model mice(P<0-001). CB-NGF nasal administration significantly shortened the escape latency and elevated the staying time and number of ChAT positive neuron(P<0-01).ConclusionCB-NGF treatment can improve the spatial and memory performance which may involve the neuroprotection to cholinergic system.

Key words: cholera toxin B subunit, nerve growth factor, β-amyloid protein, Morris water maze, choline acetyl transferase