Objective: To investigate the protective effect of heat shock protein 70 (HSP70) against hypoxic pulmonary hypertension (HPH) in neonatal rats.
Methods: A total of 128 neonatal rats were randomly divided into blank control group, HPH model group, empty virus group, and HSP70 group, with 32 rats in each group. Before the establishment of an HPH model, the rats in the blank control group and HPH model group were given caudal vein injection of 5 μL sterile saline, those in the empty virus group were given caudal vein injection of 5 μL Ad-GFP (1 010 PFU/mL), and those in the HSP70 group were given caudal vein injection of 5 μL Ad-HSP70 (1 010 PFU/mL). HPH model was prepared in the HPH model, empty virus, and HSP70 groups after transfection. At 3, 7, 10, and 14 days after model establishment, a multi-channel physiological recorder was used to record mean pulmonary arterial pressure (mPAP), optical and electron microscopes were used to observe the structure and remodeling parameters of pulmonary vessels, and Western blot was used to measure the protein expression of HSP70, hypoxia-inducible factor-1α (HIF-1α), endothelin-1 (ET-1), and inducible nitric oxide synthase (iNOS) in lung tissues.
Results: At 3, 7, 10, and 14 days after model establishment, the HPH model group and the empty virus group had a significantly higher mPAP than the blank control group (P<0.05). On days 7 and 10 of hypoxia, the blank control group and the HSP70 group had significantly lower MA% and MT% than the HPH model group and the empty virus group (P<0.01); on day 14 of hypoxia, the HPH model group, empty virus group, and HSP70 group had similar MA% and MT% (P>0.05), but had significantly higher MA% and MT% than the blank control group (P<0.01). On days 3, 7 and 10 of hypoxia, the HSP70 group had significantly higher protein expression of HSP70 than the HPH model group, empty virus group, and blank control group (P<0.01); the HSP70 group had significantly lower expression of HIF-1α, ET-1, and iNOS than the HPH model group and the empty virus group (P<0.05) and similar expression of HIF-1α, ET-1, and iNOS as the blank control group (P>0.05).
Conclusions: In neonatal rats with HPH, HSP70 transfection can increase the expression of HSP70 in lung tissues, downregulate the expression of HIF-1α, ET-1, and iNOS, alleviate pulmonary vascular remodeling, and reduce pulmonary artery pressure; therefore, it may become a new strategy for the treatment of HPH in neonates.
目的: 探讨热休克蛋白70（HSP70）在新生大鼠缺氧性肺动脉高压（HPH）中的保护作用。
方法: 将128只新生大鼠随机分为空白对照组、HPH模型组、空病毒对照组和HSP70组（ n=32）。建立HPH模型前分别向空白对照组和HPH模型组大鼠通过尾静脉注射5 μL无菌盐水，向空病毒对照组大鼠通过尾静脉注射5 μL Ad-GFP（1 010 PFU/mL），向HSP70组大鼠通过尾静脉注射5 μL Ad-HSP70（1 010 PFU/mL），转染后除空白对照组外，其余3组建立HPH模型。分别于建模后3、7、10、14 d，采用多导生理记录仪记录各组平均肺动脉压力（mPAP），光学及电子显微镜观察肺血管组织结构及重塑指标，Western blot法检测各组新生大鼠肺组织中HSP70、缺氧诱导因子-1α（HIF-1α）、缩血管因子内皮素-1（ET-1）、诱导型一氧化氮合酶（iNOS）蛋白表达水平。
结果: HPH模型组与空病毒对照组在3、7、10、14 d时的mPAP水平高于空白对照组（ P <0.05）。缺氧7、10 d时，空白对照组及HSP70组MA%、MT%低于HPH模型组和空病毒对照组（ P <0.01）；缺氧14 d时，HPH模型组、空病毒对照组和HSP70组MA%、MT%比较差异无统计学意义（ P > 0.05），但高于空白对照组（ P <0.01）。缺氧3、7、10 d时，HSP70组HSP70的蛋白表达水平高于HPH模型组、空病毒对照组和空白对照组（ P <0.01）；HSP70组HIF-1α、ET-1和iNOS表达水平低于HPH模型组和空病毒对照组（ P <0.05），而与空白对照组比较差异无统计学意义（ P > 0.05）。
结论: 转染HSP70可以提高HPH新生大鼠肺组织HSP70表达，下调HIF-1α、ET-1、iNOS表达，减轻肺血管重塑，降低肺动脉压力，可能成为治疗新生儿HPH的一种新策略。