Objective: To observe the effect of Huannao Yicong Prescription (, HNYC, a Chinese medical compound) extract on β-amyloid precursor protein (APP) metabolic signal transduction related protein kinase C (PKC), tyrosine amyloid protein kinase (TrKA), and glycogen synthase kinase-3 (GSK-3) in brain tissue of transgenic mouse dementia model induced by APP.
Methods: Sixty dementia model transgenic 3-month-old mice induced by APP695V717I were randomly allocated in four groups: the model group (A), the Donepezil (0.65×10(-3) g·kg(-1)·(-1))-treated group (B), and the two HNYC-treated groups (C and D) with high dosage (2.8 g·kg(-1)·(-1)) and low dosage (1.4 g·kg(-1)·(-1)) of HNYC extract, respectively, 15 mice in each group. Besides, a normal control group was set up with 15 C57BL/6J mice with the same age and genetic background as the model mice. The drugs for treatment were administered once a day by dissolving in equal-volume distilled water through gastric infusion, continued for 6 months, to mice in group A and to normal control group equal-volume distilled water was administered instead. Spatial learning and memory capacity of mice were observed by Morris water maze; their one-time escape response memory capacity was tested by diving platform; and changes of PKC, TrkA, and GSK-3 levels in hippocampus and cortex of brain were detected by Western blotting.
Results: HNYC extract showed significant effects on increasing the time of model mice for swimming through the flat roof and the swimming time and path in the fourth quadrant P<0.05 or P<0.01). Diving platform test showed that the latent times in Groups B and C were longer than that in Group A significantly (P <0.05 and P<0.01). Compared with the normal control group, PKC and TrkA protein expression levels in hippocampus and cortex of model mice's brain lowered significantly (P<0.01), while GSK-3 protein expression increased significantly (P<0.01); compared with Group A (the model group), hippocampal and cortical levels of PKC protein expression in the intervened groups (B-D) as well as those of TrkA in Group C were higher (P<0.01 or P<0.05), while hippocampal levels of GSK-3 in intervened groups were lower (P<0.01).
Conclusion: HNYC extract could obviously increase the protein expressions of PKC and TrkA and decrease the expression of GSK-3 protein in brain tissue of transgenetic mice model of dementia, and regulate APP metabolic signal transduction path, and thus to suppress the production of Aβ, which is one of the dominant mechanisms for improving learning/memory capacity of dementia model animals.