大鼠缺血后肢骨骼肌血管内皮生长因子及其受体的表达

Experimental study on angiogenesis and expressions of VEGF and its receptors in ischemic skeletal muscle

目的研究大鼠缺血后肢侧枝代偿和血管内皮生长因子(VEGF)及其受体表达的动态变化,为外源性VEGF治疗下肢缺血性疾病提供理论依据。方法切除SD大白鼠右后肢全长股动脉,随机分为9个时间组：造模后1、3 d、1、2、3、4、6、8及12周,各组5只动物。分别于造模前后和观察期末检测双后肢大、小腿肌肉Flt-1、Flk-1蛋白及mRNA表达,各组观察期末实验动物后肢动脉DSA检查。结果(1)缺血后3 d,5只大鼠右后肢出现溃疡(11．11%)；2周后,4只大鼠后肢溃疡愈合,而1只趾端坏疽(2．22%)。(2)缺血后2周,患肢侧枝形成达到高峰,12周时仍可见侧支血管显影。(3)缺血早期(3周内),VEGF及其受体的表达均较健侧显著增强(P＜0．05)；缺血中期(38周),VEGF和Flt-1表达迅速下降,Flk-1仍表达；缺血后期(8周后),VEGF及其受体的表达均低至极低水平,与对侧差异无统计学意义(P＞0．05)。结论(1)肢体缺血后自身的血管新生不能完全满足缺血组织的需要。(2)缺血早期外源性的VEGF补充是不必要的；缺血中期补充VEGF是适宜的；缺血后期在应用VEGF治疗的同时,也需要干预受体的表达。

Objective To investigate dynamic expression of angiogenesis and endogenous VEGF and its receptors in skeletal muscle under ischemia condition for the usage of exogenous VEGF to limb ischemia disease. Methods The right hindlimb ischemia model of SD rat was made by right superficial femoral artery being completely excised. Angiogenesis was detected by DSA and dynamic protein and mRNA expressions of VEGF and its receptors in ischemic skeletal muscle were investigated on the day before ischemia and day 1,3,7,14,21,28,42,56,84 after ischemia. Results 1.5 affected hindlimbs emerged ulcer （11.11% ） and 4 ulcers were healed during 2 weeks after ischemia and I became gangrene. 2. At 2 weeks after ischemia, angiogenesis was most obviously found in DSA, however, at 12 weeks the collateral vessels were also existed. 3. Before day 21 after ischemia, both mRNA and protein expressions of VEGF and its receptors were significantly increased （p〈0.05）. From day 21 to day 56, the expression of Flt-1 was rapidly decreased;VEGF were also attenuated. On the contrary, the value of Flk-1 remained at certain effective level. After day 56, all expression of VEGF and its receptors were reduced at low level which showed no statistically difference with the control limb （p〉0.05）. Conclusions The self-compensation can not meet the need of ischemia tissue. At early ischemia stage, the supplement of exogenous VEGF is not necessary; At mid ischemia stage, the supplement of exogenous VEGF is useful; At late ischemia stage, when the exogenous VEGF is applied, the expression of VEGF receptors should be managed at the sawn. e time.