高压喷射载VEGF_(165)、bFGF凝胶促缺血心肌血管新生的实验研究

An experimental study on the effect of injection of VEGF165-and bFGF-incorporated gel under high pressure on promoting angiogenesis in ischemic myocardium

目的探讨高压喷射心肌内给药的可行性以及载VEGF165、bFGF温敏型壳聚糖水凝胶对缺血心肌的促血管新生和心肌保护作用。方法健康杂种犬32只,随机均分为单纯心肌梗死(SMI)组,高压喷射生理盐水(NS)组,高压喷射温敏型壳聚糖水凝胶(Chitosan)组,高压喷射载VEGF165、bFGF温敏型壳聚糖水凝胶(Chitosan+VEGF165+bFGF)组。结扎左冠状动脉前降支制备急性心肌梗死模型后,SMI组直接关胸,NS组、Chitosan组和Chitosan+VEGF165+bFGF组在结扎线以下左室前壁行高压喷射心肌内给药8～10次,1次/cm2。术后6周取材行组织学、免疫组化检查并计算心肌梗死面积,处死动物前行血流动力学检测。结果术后6周心肌内仅有少量壳聚糖水凝胶样物质残留,其周围无明显的炎性细胞浸润;与SMI组比较,Chitosan组和Chitosan+VEGF165+bF-GF组梗死区新生血管数量增加(P<0.05),梗死面积缩小(P<0.05),左室舒张末压和左室内压最大下降速率明显改善(P<0.05)。结论高压喷射心肌内给药安全、可行;载VEGF165、bFGF温敏型壳聚糖水凝胶心肌内注射能促进梗死区血管新生,缩小梗死面积。

Objective To explore the feasibility of high-pressure injection of VEGF165-and bFGF-incorporated thermo-sensitive chitosan hydrogel into ischemic myocardium, and to observe the effects of VEGF165-and bFGF-incorporated chitosan hydrogel on promoting angiogenesis and protection of myocardium from ischemia. Methods Thirty two dogs were randomly divided into 4 groups （8 each）： simple myocardial infarction （SMI） group, injection of normal saline （NS） under high pressure group, injection of chitosan hydrogel under high pressure group （Chitosan） and injection of VEGF165-and bFGF-incorporated chitosan hydrogel under high pressure group （Chitosan＋VEGF165＋bFGF）. Acute myocardial infarction model was reproduced by ligation of the left anterior descending coronary artery. No treatment was given in SMI group. Injection of normal saline, chitosan hydrogel or VEGF165-and bFGF-incorporated chitosan hydrogel under high pressure into the infarcted myocardium was done respectively in NS group, Chitosan group and Chitosan＋VEGF165＋bFGF group （once per square centimeter, a total of 8 to 10 times）. The animals were sacrificed 6 weeks after treatment, the hearts were harvested and sectioned for histological and immunohistochemical detection, and the infarction size was measured, hemodynamic monitoring was performed before animals were sacrificed. Results Only a little residue was found 6 weeks after chitosan hydrogel injection with no obvious infiltration of inflammatory cell. Compared with SMI group, the number of neogenetic vessels was increased, infarction size reduced, and left ventricular end-diastolic pressure and the maximum decreasing rate of internal left ventricular pressure improved in chitosan group and chitosan＋VEGF165＋bFGF group （P0.05）. Conclusion Treatment of injection of VEGF165-and bFGF-incorporated thermo-sensitive chitosan hydrogel into ischemic myocardium under high pressure is safe and feasible, and can promote angiogenesis in infarcted myocardium and reduce infarction size.