Objective: To observe the therapeutic angiogenesis effect of naotai recipe (NR) on local ischemia/reperfusion (I/R) injury of rats by observing signaling pathway of hypoxia-inducible factor-lα (HIF-1α) and vascular endothelial growth factor (VEGF).
Methods: Totally 120 Sprague-Dawley (SD) rats were randomly divided into 4 groups, namely, the normal control group (n =12), the sham-operation group (n =12), the I/R model group (n =48), and the NR group (n =48). Cerebral I/R injury models were established using thread suture method. Rats in the I/R model group and the NR group were sub-divided into 4 sub-groups according to the 1st, 3rd, 5th, and 7th I/R day (n =12). The phenomenon of neovasculization was observed by immunofluorescence staining. The protein and mRNA expression levels of HIF-la, VEGF-A, and VEGFR II receptor were detected by RT-PCR.
Results: There were a large amount of labels for neovasculization in the ischemic area of the NR group. Double-immunofluorescence labeling [vWF (red) and BrdU (green)] was observed in the NR group. Compared with the model group, the HIF-1α protein expression was obviously enhanced on the 1 st day of I/R (P <0.01), and the VEGF protein expression started to enhance on the 3rd day in the NR group (P <0.01). The VEGFR protein expression level was the highest in the NR group on the 5th day of I/R (P <0.01). The protein expression of VEGF and HIF-1α started to decrease on the 7th day of I/R.
Conclusion: NR could strengthen angiogenesis after I/R by elevating the expression of HIF-lα and activating HIF-lα/VEGF signaling pathway.