二氯乙酸盐对肺动脉高压大鼠肺组织KV1.5表达的影响

Effect of dichioroacetate on expression of Kv1.5 in a rat model of pulmonary arterial hypertension

目的探讨二氯乙酸盐对肺动脉高压大鼠肺组织Kv1.5表达的影响。方法雄性SD大鼠32只，8周龄，体重200～250g，采用随机数字表法，将大鼠随机分为4组（n=8）：正常对照组（C组）、二氯乙酸盐对照组（D组）、肺动脉高压组（PAH组）和二氯乙酸盐治疗组（PD组）。采用左肺切除术联合皮下注射野百合碱60mg／kg的方法制备肺动脉高压模型。PD组于皮下注射野百合碱后，给予二氯乙酸盐80mg／kg灌胃，1次／d，连续28d，PAH组给予等量生理盐水；D组不制备模型，给予相同剂量二氯乙酸盐灌胃。于皮下注射野百合碱后28d时测定肺动脉压（PAP），随后处死，取肺组织，计算肺小动脉中膜厚度百分比和右心室肥厚指数，采用Western blot法检测增殖细胞核抗原（PCNA）和Kv1.5蛋白的表达水平，采用RT-PCR法检测Kv1.5，mRNA的表达水平。结果与C组比较，PAH组和PD组PAP、中膜厚度百分比及右心室肥厚指数升高，肺组织Kv1.5 mRNA及其蛋白表达下调，PCNA表达上调（P〈0．05），D组上述指标差异无统计学意义（P〉0．05）；与PAH组比较，PD组PAP、中膜厚度百分比及右心室肥厚指数降低，肺组织Kv1.5 mRNA及其蛋白表达上调，PCNA表达下调（P〈0．05）。结论二氯乙酸盐减轻大鼠肺动脉高压与上调肺组织Kv1.5，表达，抑制肺血管重构有关。

Objective To investigate the effect of dichloroacetate on the expression of Kv1.5 in a rat model of pulmonary arterial hypertension （PAH） . Methods Thirty-two male SD rats weighing 200-250 g were randomly divided into 4 groups （n = 8 each）： normal control group （group C）, dichloroaeetate control group （group D）, PAH group, and PAH ＋ dichloroacetate group （group PD） . PAH was induced by left lung resection combined with subcutaneous injection of monocrotaline 60 mg/kg in PAH and PD groups. In group PD, dichloroacetate 80 mg/kg was given through a gastric tube into stomach once a day for 28 consecutive days after monocrotaline injection, while the equal volume of normal saline was given instead of dichloroacetate in group PAH. Group D only received dichloroacetate 80 mg/kg through a gastric tube into stomach once a day for 28 consecutive days. Pulmonary arterial pressure （PAP） was measured at day 28 after monocrotaline injection. The rats were then sacrificed and lung tissues were removed to calculate the percentage of thickness of the tunica media of pulmonary artery and right ventricular hypertrophy index and to determine the proliferating cell nuclear antigen （PCNA） and Kv1.5 protein expression （by Western blot） and Kv1.5 mRNA expression （by RT-PCR）.Results Compared with group C, the PAP, percentage of thickness of the tunica media, right ventricnlar hypertrophy index were significantly increased, Kv1.5 mRNA and protein expression was down-regulated and PCNA expression was up-regulated in groups PAH and PD （P 〈 0.05）. Compared with group PAH, the PAP, percentage of thickness of the tunica media, right ventricular hypertrophy index were significantly decreased, Kv1.5 mRNA and protein expression was up-regulated and PCNA expression was down-regulated in group PD （ P 〈 0.05）. There was no significant difference in the indexes mentioned above between group C and group D （ P 〉 0.05 ）. Conclusion Dichloroacetat alleviates PAH through upregulating Kv1.5 expression in lung tissues and inhibiting puhnonary vascular remodeling in rats.