| Background and ObjectiveWith the improvement of people’s living standards, change of diet and lifestyle, and the acceleration of the aging, the incidence of ischemic cerebrovascular disease is increasing year by year, which endangers people’s health heavily. So it become a research hotspot for exploring of the pathogenesis and searching for effective therapy. Cerebral ischemic lesion is divided into ischemia core and the ischemic penumbra, and because the damages of ischemic penumbra is reversible, it is concerned that it can favor neuronal repair by recovering blood supply in ischemic penumbra. It is important of the neovascularization in ischemic penumbra. How to effectively stimulate angiogenesis, which can restore blood supply in ischemia penumbra and improve patient’s prognosis, become very valuable.Sonic hedgehog (Shh) signaling pathway is one of the hedgehog signaling pathway, which plays an important role in the development and differentiation of the nervous system. Recent studies have found that Shh signaling pathway and angiogenesis are closely linked. Shh signaling pathways can promote the diameter and length of new blood vessels, and can affect the secretion of various angiogenesis factor, such as VEGF, CD105, ANG, etc. Vascular endothelial growth factor (VEGF) is the most effective pro-angiogenesis factor which promotes the proliferation and split-up of endothelial cells. CD105is closely related with neovascular endothelial cells which can be an molecular marker of neovascularization. The research on Shh signal pathway is mainly focused in tumor, but there were few study on influence of SHH signaling pathway on angiogenesis in acute cerebral ischemia.Shh signal pathway consists of Shh protein, Ptch protein, Smo protein, Gli protein.Ptch protein is major downstream target genes in the Shh signaling pathway.When Shh signaling pathway is activated, the Ptch Protein expression is elevated. So Ptch protein increased expression is often considered a sign of Shh signaling pathway. Purmorphamine, which is a specific agonists on Shh signaling pathways, can combine with Smo protein in Shh signaling pathways. In this study, acute cerebral artery occlusion model in rats was made by middle cerebral artery occlusion to observe the effect of activation of the Shh pathway by using Purmorphamine at6h,12h,24h,48h after cerebral infarction on the expression of VEGF and CD105levels in ischemia penumbra. We aimed to explore the effect of Shh signaling pathways activation on angiogenesis in rats with acute cerebral ischemia, which could provide a new direction for the therapy of cerebral ischemia.Materials and methodsThe SD rats model with permanent middle cerebral artery occlusion was performed according to Zea longa’s report. Adult male rats (250g-350g in weight) were selected and divided randomly into three groups:sham operation group, model group and treatment group. Model group and ischemic treatment group were divided to four subgroups:6h,12h,24h,48h. Purmorphamine powder was completely dissolved into a solution with dimethyl formamide (DMF). The treatment group was given intraperitoneal injection of purmorphamine0.69mg/kg after the operation, while sham operation group and model group were given equal doses of dimethylformamide solution by intraperitoneal injection. We observed neurological deficit scores at each time point. All the rats were sacrificed and the brains were removed at a given time point. The expression of CD105and VEGF in ischemia penumbra of rats was observed by immunohistochemistry and the expression of PTCH-1was detected by RT-PCR.Results1.The expression of CD105The expression of CD105in brain tissue in sham group was low while the expression of CD105in brain tissue in the model group and treatment group were higher.(P<0.05), and the difference is statistically significant. The expression of CD105in ischemic penumbra region of model group and the treatment group began to increase at6h, which persisted to the48h after cerebral ischemia. The expression of CD105in treatment group were increased compared with model group in different time points and the difference is statisticall significant.2.The expression of VEGFA small amount of positive cells of VEGF can be observed in brain tissue of sham group. The expression of VEGF in the brain tissue of model group and treatment group began to increase at6h after operation and reached the peak at48h. The expression of VEGF in treatment group were increased compared with model group in different time points and the difference has statistical significance (P<0.05).3.The expression of PtchThe mRNA levels of Ptch in sham group were lower than those of the model group and treatment group. The difference has statistical significance. The expression of Ptch of the model group and treatment group began to increase at6h, reached the peak at24h, and began to decrease at48h. The expression of Ptch in treatment group was increased compared with model group in different time points and the difference has statistical significance.(P<0.05)Conclusions1.The Shh signaling pathway can be effectively activatd by the administration of purmorphamine, an exogenous Shh signaling pathway activator.2.Shh signaling pathway is closely related to cerebral ischemia revasculari zation. Activation of the Shh pathway in acute cerebral ischemia could increas e the expression of CD105and VEGF, which can be useful to promote angio genesis in rats with cerebral ischemia. |
PDF Full Text Request