血管内皮生长因子A对缺氧性肺动脉高压新生大鼠肺血管重塑的影响及其机制研究

Effect and mechanism of vascular endothelial growth factor-A on pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension

摘要:

目的 探讨血管内皮生长因子A（VEGF-A）调控生存素（SVV）在缺氧性肺动脉高压（HPH）新生大鼠肺血管重塑中的作用。方法 96只新生大鼠随机分为HPH+VEGF-A组、HPH组和对照组，每组再随机分为3 d、7 d、10 d和14 d亚组，每个亚组8只大鼠。HPH+VEGF-A组和HPH组分别经气管内转染携带/不携带VEGF-A的腺病毒载体后建立HPH模型，对照组气管内注射0.9% NaCl溶液后常氧下饲养。直接测压法测定新生大鼠平均右心室收缩压（RVSP）；苏木精-伊红染色后光镜下观察肺血管形态学变化，计算肺小动脉中层血管壁厚度占肺小动脉外径的百分比（MT%）和肺小动脉中层横截面积占总横截面积的百分比（MA%）；免疫组化法检测肺组织中VEGF-A和SVV的表达水平。结果 HPH组新生大鼠平均RVSP高于同时间点对照组和HPH+VEGF-A组（P < 0.05）。缺氧7 d，HPH组出现肺血管重塑，HPH+VEGF-A组自缺氧10 d开始出现。缺氧7 d时，HPH组MT%和MA%高于对照组和HPH+VEGF-A组（P < 0.05）；缺氧10 d和14 d时，HPH组及HPH+VEGF-A组MT%和MA%均高于对照组（P < 0.05）。缺氧各时间点HPH组和HPH+VEGF-A组VEGF-A表达均高于对照组（P < 0.05）；缺氧3 d和7 d时，HPH+VEGF-A组VEGF-A表达高于HPH组（P < 0.05）。缺氧14 d时，HPH组SVV表达高于对照组（P < 0.05）；缺氧各时间点HPH+VEGF-A组SVV表达均高于对照组（P < 0.05）；缺氧3 d和7 d时，HPH+VEGF-A组SVV表达高于HPH组（P < 0.05）。结论 预防性外源性气管内给予HPH新生大鼠VEGF-A，可在缺氧早期通过上调SVV表达抑制肺血管重塑，降低肺动脉压力，为新生儿HPH肺血管重塑干预治疗提供了依据。

Abstract:

Objective To study the role of vascular endothelial growth factor-A (VEGF-A) in pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension (HPH) by regulating survivin (SVV). Methods A total of 96 neonatal rats were randomly divided into three groups: HPH+VEGF-A group, HPH group, and control group. Each group was further randomly divided into 3-, 7-, 10-, and 14-day subgroups (n=8 in each subgroup). The neonatal rats in the HPH+VEGF-A and HPH groups were intratracheally transfected with adenoviral vectors with or without VEGF-A gene respectively. Those in the control group were given intratracheal injection of normal saline and were then fed under normoxic conditions. The direct measurement method was used to measure mean right ventricular systolic pressure (RVSP). Hematoxylin-eosin staining was used to observe the morphological changes of pulmonary vessels under a light microscope and calculate the percentage of media wall thickness (MT%) and the percentage of media wall cross-sectional area (MA%) in the pulmonary arterioles. Immunohistochemistry was used to measure the expression levels of VEGF-A and SVV in lung tissue. Results The HPH group had a significantly higher mean RVSP than the control and HPH+VEGF-A groups at each time point (P < 0.05). Pulmonary vascular remodeling occurred in the HPH group on day 7 of hypoxia, while it occurred in the HPH+VEGF-A group on day 10 of hypoxia. On day 7 of hypoxia, the HPH group had significantly higher MT% and MA% than the control and HPH+VEGF-A groups (P < 0.05). On days 10 and 14 of hypoxia, the HPH and HPH+VEGF-A groups had significantly higher MT% and MA% than the control group (P < 0.05). The HPH and HPH+VEGF-A groups had significantly higher expression of VEGF-A than the control group at each time point (P < 0.05). On days 3 and 7 of hypoxia, the HPH+VEGF-A group had significantly higher expression of VEGF-A than the HPH group (P < 0.05). On day 14 of hypoxia, the HPH group had significantly higher expression of SVV than the control group (P < 0.05). The HPH+VEGF-A group had significantly higher expression of SVV than the control group at each time point (P < 0.05). On days 3 and 7 of hypoxia, the HPH+VEGF-A group had significantly higher expression of SVV than the HPH group (P < 0.05). Conclusions Prophylactic intratracheal administration of exogenous VEGF-A in neonatal rats with HPH can inhibit pulmonary vascular remodeling and reduce pulmonary arterial pressure by upregulating the expression of SVV in the early stage of hypoxia. This provides a basis for the interventional treatment of pulmonary vascular remodeling in neonatal HPH.