二十二碳六烯酸干预低氧诱导大鼠肺动脉高压的研究

Effects of docosahexaenoic acid on hypoxia-induced pulmonary arterial hypertension

目的 探讨二十二碳六烯酸（DHA）对低氧性肺动脉高压的影响及机制.方法 实验SD大鼠分为常氧组、常氧DHA组、低氧组和低氧DHA组.肺动脉高压模型采用间断低氧法,大鼠肺小动脉形态学采用HE染色,肺动脉平滑肌细胞（PASMCs）采用组织贴块法,细胞增殖及迁移分别采用噻唑蓝比色法和改良Boyden小室法.α-肌动蛋白、调宁蛋白和肌动蛋白相关蛋白（SM22α） mRNA水平采用RT-PCR法.结果 低氧组大鼠平均肺动脉压力[mPAP,（30.1±2.6） mmHg,1 mmHg=0.133 kPa],右心室肥厚指数[RV/（LV ＋S）,（40.4±4.2）％],肺小动脉管壁厚度与外径比值[WT％,（44.6±4.1）％]及管壁面积占血管总面积的百分比[WA％,（81.2±5.4）％]与常氧对照组相比均明显升高[mPAP：（18.4±1.2） mmHg；RV/（LV＋S）：（27.8±1.6）％；WT％：（17.7±3.3）％;WA％：（42.9±3.5）％,P＜0.05]；DHA干预的低氧组大鼠上述各指标[mPAP为（22.7±1.8）mmHg,RV/（LV ＋S）为（34.2±2.2）％,WT％为（21.6±4.1）％,WA％为（52.0±2.9）％]均低于低氧组（P＜0.05）；常氧DHA组,低氧DHA组与常氧组相比,上述指标无显著差别.在体外,DHA能显著抑制低氧诱导的PASMCs增殖、迁移（P＜0.05）.低氧时DHA能促进α-肌动蛋白,调宁蛋白和SM22α的mRNA表达.结论 DHA对低氧所致的肺动脉高压具有较好的抑制作用,其机制可能是通过抑制PASMCs增殖,迁移和表型转换而起作用.

Objective To investigate the effects of docosahexaenoic acid （DHA） on hypoxiainduced pulmonary arterial hypertension （PAH） and the mechanism.Methods PAH was induced by chronic intermittent hypoxia for 21 days in vivo.Forty male Sprague-Dawley rats were randomly divided into 4 groups （n =10,each）：a normal control group,DHA-treated groups in normoxia and hypoxia,and a PAH group.At the end of study,mean pulmonary arterial pressure （mPAP）,right ventricular hypertrophy and the index of wall thickness of small pulmonary artery （WT% and WA%） among groups were compared.The changes of pulmonary arterial smooth muscle cell （PASMC） proliferation were determined by MTT in vitro.Migration assay was performed using the Boyden chamber.Real-time quantitative PCR was performed to quantify mRNA levels of the smooth muscle cell phenotype markers SM-α-actin,calponin and SM 22α under normoxic or hypoxic conditions,in the absence or presence of DHA.Results DHA treatment significantly lowered mPAP[（22.7 ± 1.8） mmHg （1 mmHg =0.133 kPa）],reduced thickening of small pulmonary artery wall[WT%：（21.6 ± 4.1） %,WA%：（52.0 ± 2.9） %] and alleviated ventricular hypertrophy （34.2 ± 2.2） % compared to those of the hypoxic group （P 〈 0.05）.DHA inhibited the proliferation,migration and phenotype switching of PASMCs induced by hypoxia in vitro.Conclusion DHA therapy reduced mPAP in a rat model of hypoxia-induced PAH and this effect was linked with inhibition of pulmonary vascular remodelling.