游泳运动对低氧性肺动脉高压大鼠肺组织apelin及其受体表达的影响

目的:探讨游泳运动对大鼠肺组织新的小分子活性肽apelin及其受体(APJ)表达的影响。方法:45只雄性大鼠随机分成三组:正常对照组、低氧组(七周)和游泳组(低氧+游泳锻炼七周组,低氧3周后,于每天入低氧舱前行无负重游泳运动60 min,每天1次)。七周后测定各组大鼠平均肺动脉压(mPAP)、右心室与左心室加室间隔的重量比RV/(LV+S)]、肺细小动脉管壁面积/管总面积(WA/TA)、管腔面积/管总面积(CA/TA)及中膜厚度(PAMT)。免疫蛋白印迹与免疫组化法测定肺组织apelin/APJ的蛋白表达。结果:①低氧组mPAP和RV/(LV+S)比正常对照组分别高73.6%和31.2%(P均<0.01),而游泳组比低氧组分别低21.1%和8.9%(P均<0.05)。②低氧组WA/TA和PAMT较正常对照组分别高70.8%和102%,而游泳组较低氧组分别低24.8%和40.1%(P均<0.01)。低氧组CA/TA较正常对照组低15.1%,而游泳组较低氧组高10.3%(P均<0.01)。③低氧组肺组织apelin蛋白表达较正常对照组上调374%(P<0.01),而APJ蛋白表达下调87.1%(P均<0.01);游泳组肺组织apelin蛋白表达较低氧组下调48%,而APJ蛋白表达上调287%(P均<0.01)。④apelin蛋白主要在血管外膜及炎症细胞胞浆内表达,APJ蛋白主要在血管内膜、外膜及炎症细胞上表达。结论:游泳运动减缓肺动脉高压和肺血管重塑作用可能与调节肺组织apelin/APJ系统的表达有关。

Effect of swimming exercise on the expression of apelin and its receptor in pulmonary tissues of rats with hypoxic pulmonary hypertension

Objective: To study the effects of swimming exercise on the expression of apelin and its receptor(APJ) system in pulmonary tissues of rats with pulmonary hypertension induced by hypoxia.Methods: Forty-five male SD rats were randomly divided into control group,hypoxia group(seven-week) and swimming group(four-week swimming group after three-week hypoxia).The animal model of hypoxic pulmonary hypertension was established by exposing the rats to isobaric hypoxic chamber(8 h/d,6 d/w).The rats of swimming group swam 60 min/ day,7 d/week for 4 weeks after three-week hypoxia.The mean pulmonary arterial pressure(mPAP) and the mean carotid arterial pressure(mCAP) were measured by either right or left cardiac catheterization,and the weight ratio of right ventricule/left ventricle plus septum were calculated.The Masson’s trichrome stained lung specimens were used by light microscope to examine the vessel wall area/total area(WA/TA),vessel cavity area/total area(CA/TA) and media thickness of pulmonary arterioles(PAMT).Meanwhile,apelin/APJ expressions were determined by Western blot and immunohistochemistry.Results: ①mPAP and RV/(LV+S) of hypoxia group were higher than those of control group by 73.6% and 31.2%(P<0.01),and mPAP and RV/(LV+S) of swimming group were lower than those of hypoxia group by 21.1%and 8.9 %(P<0.05),respectively.②Masson’s trichrome staining revealed that WA/TA and PAMT of hypoxia group were higher than those of control group by 70.8% and 102%.However,WA/TA and PAMT of swimming group were lower than those of hypoxia group by 24.8% and 40.1%(all P<0.01),respectively.CA/TA of hypoxia group was lower than that of control group by 15.1%,and CA/TA of swimming group was lower than that of hypoxia group by 10.3%(all P<0.01).③Compared with control group,hypoxia group showed up-regulated apelin expression and down-regulated APJ expression in pulmonary tissues(all P<0.01).Compared with hypoxia group,swimming group showed decreased apelin expression and elevated APJ expression in pulmonary tissues(all P<0.01).④Apelin localized mainly in intracytoplasm of inflammatory cell and tunica adventitia of vessel,and APJ were in vascular intima and tunica externa and plasmalemma of inflammatory cell.Conclusion: The improving effect of swimming exercise on hypoxic pulmonary hypertension in rats could be mediated by regulating the pulmonary apelin/APJ system.