花生四烯酸细胞色素p450表氧化酶基因对肺动脉高压大鼠血浆和组织中ET-1、NO、TXA2和PGI2变化的影响

目的观察野百合碱(MCT)诱导的肺动脉高压大鼠中花生四烯酸色素p450表氧化酶CYP2J2基因过表达时血浆和肺组织中内皮素-l(ET-1)、一氧化氮(NO)血栓素A2(TXA2)和前列腺素I2(PGI2)的水平及肺组织中一氧化氮合酶(NOS)活性的变化。方法成年雄性SD大鼠60只随机分为正常对照组(n=30)和MCT模型组(n=30),皮下注射MCT(60mg/kg)建立肺动脉高压模型。三周后尾静脉分别注射生理盐水和质粒分为6组:NS组,pCDNA3.1(n=10),pcDNA3.1-CYP2J2(n=10),MCT+NS(n=10),MCT+pCDNA3.1(n=10),MCT+pCDNA3.1-CYP2J2(n=10)。三周后,检测大鼠肺动脉压(mPAP),测定血浆和肺组织中ET-1和NO水平,检测肺组织中NOS和eNOS的活性,检测血浆和肺组织TXA2代谢产物TXB2和PGI2代谢产物6-酮-前列腺素1α(6-keto-PGF1α)水平及TXB2/6-keto-PGF1α的比值。结果 MCT模型组mPAP,血浆和肺组织中ET-1水平和TXB2含量和TXB2/6-keto-PGF1α比值均明显高于正常对照组(P<0.05),而pCDNA3.1-CYP2J2治疗组与MCT模型组比均显著降低(P<0.05),但仍高于正常对照组(P<0.05);MCT模型组血浆和肺组织中NO和6-keto-PGF1α含量,肺组织eNOS和NOS活性,TXB2/6-keto-PGF1α比值均明显低于正常对照组(P<0.05),而pCDNA3.1-CYP2J2治疗组均明显增高(P<0.05),但仍低于正常对照组(P<0.05)。结论花生四烯酸色素p450表氧化酶基因CYP2J2可逆转MCT诱导的肺动脉高压,其机制可能与降低肺组织和血浆中的ET-1和TXA2含量,升高PGI2含量,上调TXA2/PGI2比值,上调机体内eNOS和总NOS活性,增加体内NO水平有关。CYP2J2基因治疗对肺动脉高压有积极的治疗作用。

The effect of cytochrome P450 epoxygenase gene on plasma and lung level of ET-1 and NO in monocrotaline-induced pulmonary hypertension

Objective To determine the effect of Cytochrome P450 epoxygenase 2J2(CYP2J2) on the level changes of plasma and lung endothelin 1(ET-1),NO,thromboxane A2(TXA2) and prostaglandin I2(PGI2) and the acticity of NOS in lung in the rat models with pulmonary hypertension induced by monocrotaline(MCT) and explore the mechanisms.Methods Sixty male SD rats were randomly divided into 2 groups,a normal control group and a model control group,the latter was injected 60mg/kg MCT to induce pulmonary hypertension.Three weeks later,rats were divided into six groups:NS(n=10),pCDNA3.1(n=10),pCDNA3.1-CYP2J2(n=10),MCT+NS(n=10),MCT+pCDNA3.1(n=10),MCT+ pCDNA3.1-CYP2J2(n=10).After 21 days,the mean pulmonary arterial pressure(mPAP) were recorded.The level of ET-1 and NO in plasma and lung tissue and the activity of total NOS and eNOS in lung tissue were detected.The contents of TXA2,PGl2 and TXA2/PGl2 in plasma and lung tissue were measured.Results The levels of mPAP,content of plasma and lung tissue ET-1,TXA2,and TXA2/PGl2 in single MCT group were significantly increased compared with the normal group(P<0.05).The above parameters were significantly lower in the MCT+ pcDNA3.1-CYP2J2 group than in the single MCT group(P<0.05),but remained higher than in the normal group(P<0.05);The level of plasma and lung NO,PGI2,TXA2/PGl2 and the activity of lung tissue total NOS and eNOS in single MCT group were significantly decreased compared with the normal group(P<0.05),while above parameters were significantly increased in the MCT+ pcDNA3.1-CYP2J2 group than in the single MCT group(P<0.05),but remained lower than in the normal group(P<0.05).Conclusion CYP2J2 gene overpression effectively reverses the development of pulmonary hypertension in rats induced by MCT may result from the decrease of ET-1 and TXA2 in plasma and lung,increase of NO,PGI2,TXA2/PGl2 in plasma and lung,and up-regulation of activity of eNOS and NOS in lung.