Effects of Huangpu Tongqiao Capsules on EGFR-PLCγ signal pathway of hippocampus in rats with Alzheimer's disease

Abstract

Huangpu Tongqiao Capsules(HPTQC), with the functions of invigorating Qi and kidney, eliminating phlegm and removing blood stasis, have the effect of treating Alzheimer's disease(AD), but its mechanism needs further exploration. To explore the relationship between the therapeutic mechanism of HPTQC on Alzheimer's disease and EGFR-PLCγ signal pathway, 40 healthy male SD rats were selected and divided into 4 groups randomly: sham operation group(sham), model group(model), HPTQC group(HPTQC), and nimodipine group(NMP). AD rat model was established by intraperitoneal injection of D-galactose combined with an intracerebral injection of amyloid-β peptide(25-35). After 28 days of administration, Morris water maze test and HE staining showed that the learning and memory ability of AD rats were significantly decreased(P<0.01), and hippocampal neurons were obviously da-maged. However, HPTQC could improve the learning and memory ability of AD rats(P<0.05) and reduce the damage of hippocampal neurons. Immunofluorescence test results showed that the expression levels of EGFR and p-Tau in hippocampal CA1 region of AD rats were significantly increased(P<0.01), and HPTQC could reduce the expression of EGFR and p-Tau in hippocampus of AD rats(P<0.01). Western blot results showed that the protein expression levels of EGFR, PLCγ, IP3 R and p-Tau in hippocampus of AD rats were significantly increased(P<0.01), and HPTQC could reduce the protein expression of EGFR, PLCγ, IP3 R and p-Tau in AD rats(P<0.05). RT-PCR results showed that the mRNA levels of EGFR, PLCγ, IP3 R and Tau in hippocampus of AD rats were significantly increased(P<0.01), and HPTQC could reduce the mRNA levels of EGFR, PLCγ, IP3 R and Tau in AD rats(P<0.05). The results indicate that HPTQC can improve the learning and memory ability of AD rats, and its mechanism of action may be related to regulating EGFR-PLCγ signal pathway.