Expression of the receptors of VEGF and the influence of extract of Ginkgo biloba after cisternal injection of autologus arterial hemolysate in rats.

The study was aimed to investigate the alterations of vascular endothelial growth factor (VEGF) receptors and the influence of extract of Ginkgo biloba (EGb) after subarachnoid hemorrhage (SAH). Wistar rats were divided into non-SAH, SAH, vehicle, EGb1 (lower dose), and EGb2 (higher dose) groups. Autologus arterial hemolysate was injected into cisterna magna to induce SAH. The non-SAH rats received cisternal injection of saline instead. Rats underwent RT-PCR determination of one of the VEGF receptors flt-1mRNA, and immunohistochemistry for VEGF receptors Flt-1 and Flk-1. The results revealed that there was only slight expression of flt-1mRNA in the brain tissue in non-SAH rats. The expression in SAH group was enhanced 24 hours and 72 hours after cisternal injection. No Flt-1 and Flk-1 positive cell was observed in the brain in non-SAH group. A good few Flt-1 and Flk-1 positive cells were found in cortex and other regions of the brain in SAH group. The expression of flt-1mRNA, Flt-1 and Flk-1 proteins were increased by the use of two doses of EGb. It was concluded that the up-regulated expression of the two kinds of VEGF receptors may be an intrinsic protective mechanism in the process of SAH, which can be enhanced by EGb.