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目的:探讨内质网应激介导的凋亡在低氧性肺动脉高压大鼠肺组织中的变化及意义。方法:清洁级雄性SD大鼠22只随机被均分成对照组和低氧组(n=11)。采用常压低氧法复制慢性低氧高二氧化碳性肺动脉高压模型,4周后,测定肺动脉平均压(mPAP)、右心室游离壁(RV)和左心室加室间隔(LV+S)重量比、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)及肺细小动脉中膜厚度(PAMT)作为模型指标。Hoechst染色检测肺组织凋亡细胞核。RT-PCR检测肺组织中胱冬酶12(caspase12)和葡萄糖调节蛋白78与94(GRP78、GRP94)mR-NA的表达水平。免疫组化法检测肺组织GRP78、GRP94蛋白的表达。结果:①与对照组相比,低氧组mPAP高50.5%,RV/(LV+S)高37.3%,WA/TA高72.5%,PAMT高137%,而CA/TA低41.9%(均P<0.01)。②Hoechst染色结果显示低氧组肺泡上皮细胞及肺血管内皮细胞可见较多呈高蓝光细胞核,肺血管中膜平滑肌细胞见低蓝光细胞核。③半定量RT-PCR结果显示,与对照组相比,低氧组肺组织caspase12 mRNA高144%,GRP78 mRNA高137%,GRP94 mRNA高80.7%(均P<0.05)。④免疫组化半定量结果显示,低氧组GRP78、GRP94蛋白明显高于对照组(均P<0.01),棕黄色颗粒表达主要位于肺泡上皮细胞及肺血管内皮细胞,而中层平滑肌层表达不明显。结论:内质网应激介导的凋亡与大鼠慢性低氧性肺动脉高压、肺血管改建的病理过程有关。
Objective: To investigate the changes and significance of endoplasmic reticulum stress-induced apoptosis in lung tissue of hypoxic pulmonary hypertensive rats. Methods: Twenty-two male SD rats were randomly divided into control group and hypoxia group (n = 11). The model of chronic hypoxia and hypercapnia pulmonary hypertension was established by the normal-pressure hypoxia method. After 4 weeks, the mean pulmonary artery pressure (mPAP), right ventricular free wall (RV) and left ventricular compartment (LV + S) The area of small arteries, total wall area (WA / TA), luminal area / total area (CA / TA) and pulmonary arterial thickness (PAMT) Hoechst staining was used to detect apoptotic nuclei in lung tissue. The mRNA expression levels of caspase 12 and glucose regulatory proteins 78 and 94 (GRP78, GRP94) mR-NA in lung tissue were detected by RT-PCR. Immunohistochemistry was used to detect the expression of GRP78 and GRP94 in lung tissue. Results: Compared with the control group, mPAP was 50.5%, RV / (LV + S) was 37.3%, WA / TA was 72.5%, PAMT was 137% and CA / TA was 41.9% <0.01). Hoechst staining showed that in hypoxic group, alveolar epithelial cells and pulmonary vascular endothelial cells showed high blue nuclei, and pulmonary vascular smooth muscle cells showed low blue light nuclei. ③ The results of semi-quantitative RT-PCR showed that compared with the control group, the expression of caspase12 mRNA in lung tissue of hypoxia group was 144% higher, GRP78 mRNA was 137% higher and GRP94 mRNA was 80.7% higher (all P <0.05). ④ Semiquantitative results of immunohistochemistry showed that the expression of GRP78 and GRP94 protein in hypoxia group was significantly higher than that in control group (all P <0.01). The expression of brown granules was mainly located in alveolar epithelial cells and pulmonary vascular endothelial cells, while the expression of mid-smooth muscle layer was not obvious . Conclusion: Endoplasmic reticulum stress-induced apoptosis is associated with pathological process of chronic hypoxic pulmonary hypertension and pulmonary vascular remodeling in rats.