Apelin对改善小鼠低氧性肺动脉高压的作用及与调节脂质代谢的关系

Apelin attenuates hypoxia induced pulmonary hypertension of mice through regulation of lipid metabolism

目的:探讨外源性apelin对小鼠慢性低氧性肺动脉高压的作用及其机制。方法:SPF级雄性apo E基因敲除(apo E-KO)小鼠30只,随机均分为3组(n=10),即常氧组、低氧组和低氧+apelin组,apelin组小鼠每天于低氧前经腹腔注射apelin-13(10 nmol/(kg·d)),其他组腹腔注射相同体积的生理盐水。采用常压连续低氧方法(9%~11%O_)2,23 h/d)复制慢性低氧性肺动脉高压模型。低氧3周后,采用右心导管法测定小鼠右心室压(RVSP)和右心室与左心室加室间隔重量比[RV/(LV+S)],Elisa法检测血浆中高密度脂蛋白(HDL)、低密度脂蛋白(LDL)和总胆固醇(TC)的含量;real-time PCR法检测肝组织中三磷酸腺苷结合盒转运体A1(ABCA1)、清道夫受体B1(SR-B1)、低密度脂蛋白受体(LDLR)和3-羟基-3-甲基戊二酸单酰辅酶A还原酶(HMGCR)等基因的表达。Western blot法检测小鼠肺组织中过氧化物酶体增殖物激活受体γ(PPARγ)蛋白的表达。结果:(1)低氧组小鼠RVSP、RV/(LV+S)较常氧组分别高87%、85%(P均<0.05),apelin组小鼠RVSP、RV/(LV+S)较低氧组分别低39%、33%(P均<0.05)。(2)apelin组小鼠血浆中HDL-C含量、HDL/LDL比值分别较hypoxia组高21%、20%(P均<0.05),而血浆中TC、LDL-C含量两组间无显著差异(P均>0.05)。(3)apelin组小鼠肝组织中LDLR、SR-B1、ABCA1基因表达分别较低氧组上调241%、112%、69%(P均<0.05),而HMGCR基因表达下调45%(P<0.05)。(4)apelin组小鼠肺组织中PPARγ蛋白表达较低氧组上调47%。结论:Apelin可降低小鼠低氧性肺动脉高压,其机制与调节脂质代谢有关。

Objective： To observe the role of apelin in the prevention of pulmonary hypertension induced by hypoxia in mice. Methods： Adult male apoE gene knockout （apoE-KO） mice were exposed to isobaric hypoxic chamber （9% ～ 11% 02, regular chow feed, 23 h/d）for 3 weeks to establish hypoxia-induced pulmonary hypertension. Thirty apoE-KO mice were randomly divided into normoxia group, hypoxia group and hypoxic with apelin （10 nmol/（kg ·d）, ip） group. The concentrations of high density lipoprotein （HDL）, low density lipoprotein （LDL） and total cholesterol in plasma were detected by Elisa method. The mRNA levels of ATP-binding cassette transporter A1 （ABCA1）, low density lipoprotein receptor （LDLR）, scavenger receptor class BI （SR-B1）, and HMG-CoA reductase （HMGCR）in liver were measured by real-time PCR. The protein level of peroxisome proliferators-activated receptor gamma （PPAR7） in lung was measured by Western blot. Results： ①The right veutricular systolic pressure （RVSP） and the weight ratio of right ventricle （RV） to left ventricle plus septum （LV ＋ S） of hypoxia group were significantly higher than those of normoxia group by 87 % and 85 % （ P 〈 0.05）, respectively. RVSP and RV/（ LV ＋ S） of apolin group were significantly lower than those of hypoxia group by 39% and 33% （ P 〈 0.05）, respectively. ②The plasma concentration of HDL and HDL/LDL of apelin group were significantly higher than those of hypoxia group by 21% and 20% （ P 〈 0.05）, respectively. ③The mRNA levels of LDLR, SR-B1 and ABCA1 in liver of apelin group were significantly up-regulated than those of hypoxia group by 241%, 112% and 69% （ P 〈 0.05）, respectively, while the mRNA level of HMGCR was down-regulated by 45% （ P 〈 0.05）. ④The protein level of PPARy in lung of apelin group was significantly up-regulated than that of hypoxia group by 47% （P 〈 0.05）. Conclusion： Apelin attenuates hypoxiainduced pulmonary hypertension of mice through regulation of lipid metabolism.