山柰酚对大鼠高原肺水肿的预防作用及机制研究

Preventive effect and mechanism of kaempferol on high altitude pulmonary edema in rats

目的:探究山柰酚干预对大鼠急性高原肺水肿的保护作用和可能存在的机制。方法:将32只雄性Sprauge-Dawley(SD)大鼠随机分为对照组(N组)、模型组(M组)、山柰酚组(KA组)和乙酰唑胺组(ACZ组),每组8只,预给药7 d后利用高原性疾病环境模拟系统(模拟海拔6000 m高原环境)建立急性高原肺水肿大鼠模型。造模完成后,观察各组大鼠肺组织病理学变化,计算肺含水量,试剂盒检测肺组织超氧化物歧化酶(SOD)和一氧化氮合酶(NOS)活性、丙二醛(MDA)含量、炎症因子肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平,并检测肺组织磷脂酰肌醇3激酶(Phosphatidylinositol-3 kinase,PI3K)、丝氨酸苏氨酸蛋白激酶(Protein-serine-threonine kinase,Akt)mRNA水平和蛋白相对含量。结果:与N组相比,M组肺含水量上升,肺水肿病理表现显著,肺组织TNF-α、IL-6水平升高(t=14.753、7.666,均P<0.01),SOD和NOS活性下降(t=9.663、4.681,均P<0.01),MDA含量上升(t=13.906,P<0.01);与M组比较,KA组的肺含水量降低,肺水肿病理表现减轻,炎症因子TNF-α和IL-6水平均明显下降(t=9.104、3.843,均P<0.01),SOD活性上升(t=3.715,P<0.01),NOS活性上升(t=2.629,P<0.05),MDA含量下降(t=9.196,P<0.01)。与N组相比,M组PI3K、Akt1 mRNA表达水平升高(t=7.069、5.896,均P<0.01)、蛋白相对含量升高(t=3.552、7.930,均P<0.05);与M组比较,KA组PI3K、Akt1 mRNA表达水平降低(t=8.468、5.871,均P<0.01)、蛋白含量降低(t=6.701、4.010,均P<0.05)。结论:山柰酚可以通过减轻氧化损伤和抑制炎症反应,预防低压低氧诱导的急性高原肺水肿的发生,这种保护作用可能与下调PI3K/Akt信号通路有关。

Objective:To explore the protective effect and possible mechanism of kaempferol intervention on acute high altitude pulmonary edema in rats.Methods:Thirty-two male Sprauge-Dawley(SD)rats were randomly divided into control group(N group),model group(M group),kaempferol group(KA group)and acetazolamide group(ACZ group),with 8 rats in each group.After 7 days of pre-administration,the acute high altitude pulmonary edema model was established through a high-altitude disease environment simulation system(simulating environment of 6000 m at high altitude).After the modeling was completed,the pathological changes of lung tissue,the lung wet/dry ratio,superoxide dismutase(SOD),nitric oxide synthase(NOS),malondialdehyde(MDA),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)levels,the mRNA level and protein expression of phosphatidylinositol 3 kinase(PI3K)and serine threonine protein kinase(Akt)were detected.Results:Compared with group N,group M showed increased wet/dry ratio,marked pathological changes,increased levels of TNF-αand IL-6 in lung tissues(t=14.753,7.666,both P<0.01),and decreased SOD and NOS activities(t=9.663,4.681,both P<0.01),the content of MDA increased(t=13.906,P<0.01).Compared with group M,the wet/dry ratio of group KA was reduced,the pathological manifestations of pulmonary edema were alleviated,and the levels of TNF-αand IL-6 decreased significantly(t=9.104,3.839,both P<0.01),SOD and NOS activity increased(t=3.715,2.629,P<0.01,P<0.05),MDA content decreased(t=9.196,P<0.01).Compared with group N,the PI3K and Akt1 mRNA expression of group M increased(t=7.069,5.896,both P<0.01),and the protein content increased(t=3.552,7.930,both P<0.05);compared withgroup M,PI3K and Akt1 mRNA expression levels in the KA group decreased(t=8.468,5.871,both P<0.01),and protein content decreased(t=6.701,4.010,both P<0.05).Conclusion:Kaempferol can prevent the occurrence of acute high altitude pulmonary edema induced by low pressure and hypoxia by reducing oxidative damage and inhibiting inflammation.This protective effect may be related to the down-regulation of PI3K/Akt signal pathway.