Mechanism of Danlong Xingnao Formula Promoting Angiogenesis in Rats with Vascular Dementia Based on Nrf2/Keap1 Pathway

OBJECTIVE  To investigate the effect and mechanism of Danlong Xingnao Formula on angiogenesis in vascular dementia(VD) rats based on the nuclear factor E2 related factor 2(Nrf2)/Kelch like epichlorohydrin related protein-1(Keap1) signaling pathway.

METHODS  SD rats were give modified bilateral common carotid artery occlusion to establish VD rat model. SD rats were randomly divided into model group, Nimodipine group, Danlong Xingnao Formula high-dose(14.8 g·kg⁻¹) group, Danlong Xingnao Formula medium-dose(7.4 g·kg⁻¹) group and Danlong Xingnao Formula low-dose(3.7 g·kg⁻¹) group with 10 rats in each group. Administer corresponding medication by gavage separately, at the same time, the sham operation group was given the same amount of normal saline, all rats were treated for 4 weeks. Morris water maze test to detect escape latency and cross-platform times. The pathomorphological changes of rat hippocampal neurons by HE staining. Detection of microvessel density(MVD), vascular endothelial growth factor(VEGF) expression in hippocampal tissue by using immunohistochemistry. Biochemical method were used to measure the levels of glutathione(GSH), malondialdehyde(MDA), superoxidedismutase(SOD) in the hippocampal tissue. Real-time PCR method for detecting the expression of Nrf2, Keap1 and heme oxygenase 1(HO-1) mRNA in hippocampal tissue. Western blotting detection of Nrf2, Keap1 and HO-1 protein expression in hippocampal tissue.

RESULTS  Compared with the model group, the intervention of Danlong Xingnao Formula could significantly improve the learning and spatial memory abilities of model rats(P<0.05, P<0.01), alleviate pathological and morphological damage to hippocampal tissue, increase MVD and VEGF expression(P<0.05, P<0.01), increase SOD and GSH activity, reduce MDA content(P<0.05, P<0.01), and upregulate Nrf2, HO-1 mRNA and Nrf2, HO-1 protein expression(P<0.05, P<0.01), reduce the expression of Keap1 mRNA and Keap1 protein(P<0.05, P<0.01).

CONCLUSION  The Danlong Xingnao Formula reduces oxidative stress and promotes angiogenesis by activating the Nrf2/Keap1 signaling pathway, thereby improves the learning and memory abilities of VD rats.