Prolonged mechanical stretch is associated with upregulation of hypoxia-inducible factors and reduced contraction in rat inferior vena cava
Prolonged mechanical stretch is associated with upregulation of hypoxia-inducible factors and reduced contraction in rat inferior vena cava
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DOI：
10.1016/j.jvs.2010.09.018
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发表时间：
2011-03-01
影响因子：
4.3
通讯作者：
Khalil, Raouf A.
中科院分区：
文献类型：
--
作者：
Lim, Chung S.;Qiao, Xiaoying;Khalil, Raouf A.
背景：静脉张力降低和静脉壁扩张可能导致静脉曲张的形成。我们已经表明，延长静脉壁拉伸与基质金属蛋白酶（MMPs）的上调和收缩减少。由于缺氧诱导因子（HIF）的表达也随着机械牵张而增加，本研究测试HIF的上调是否是将延长的静脉壁牵张与MMP表达和静脉收缩的变化联系起来的中介机制。将大鼠下腔静脉（IVC）悬于组织浴中，基础张力为0.5g，持续1h，对照组给予苯肾上腺素（PHE，10（-5）M）和KCl（96 mM）诱导。然后将静脉暴露于0.5g、2g、2g加HIF抑制剂U 0126（10（-5）M）、17-[2-（3-氨基苯基）-1，3-二氢吲哚]-1-基]-1，3-二氢吲哚-1-甲酸酯（10（-5）M）的延长的18小时张力下。（二甲氨基）乙基]氨基-17-去甲氧基格尔德霉素（17-DMAG，10（-5）M）或棘霉素（10（-6）M），或2 g加二甲基氧烯丙基甘氨酸（DMOG; 10（-4）M），一种稳定HIF的脯氨酰羟化酶抑制剂。将PHE和KCl收缩的倍数变化与0.5 g张力下1小时的对照收缩进行比较。使用实时逆转录聚合酶链反应和蛋白质印迹分析静脉组织匀浆中的HIF-1 α、HIF-2 α、MMF-2和MMP-9信使RNA（mRNA）和蛋白质量。与0.5g张力下1小时的对照IVC收缩相比，在延长0.5-g张力后PHE和KCl收缩分别为2.0 +/- 0.35和1.1 +/- 0.06。延长2 g张力后，静脉对PHE和KCl的收缩显著减少（分别为0.87 +/- 0.13和0.72 +/- 0.05）。在暴露于延长的2-g张力加HIF抑制剂U 0126（1.38 +/- 0.15）或棘霉素（1.99 +/- 0.40）的IVC中，PHE诱导的收缩恢复。U 0126和棘霉素也恢复了暴露于延长的2g张力的NC中KCl诱导的收缩（分别为1.14 +/- 0.05和1.11 +/- 0.15）。DMOG治疗进一步降低了PHE和KCl诱导的静脉收缩（分别为0.47 +/- 0.06和0.57 +/- 0.01）。HIF-1 α和HIF-2 α mRNA在暴露于延长的2-g张力的NC中过表达，并且U 0126逆转了过表达。牵张NC中HIF-1 α和HIF-2 α的过度表达与MMP-2和MMP-9 mRNA的增加相关。HIF-1 α，HIF-2 α，MMP-2和MMP-9的蛋白量也增加NC暴露于长期2-g的wall tension.Conclusions：静脉壁张力的长期增加与HIF-1 α和HIF-2 α的过度表达，MMP-2和MMP-9的表达增加，并减少大鼠IVC的静脉收缩。连同我们的MMP-2和MMP-9抑制NC收缩的报道，数据表明静脉壁张力增加诱导HIF过表达，并导致MMP表达增加和静脉收缩减少，导致进行性静脉扩张和静脉曲张形成。（J Vase Surg 2011;53：764-73.）
Background: Decreased venous tone and vein wall dilation may contribute to varicose vein formation. We have shown that prolonged vein wall stretch is associated with upregulation of matrix metalloproteases (MMPs) and decreased contraction. Because hypoxia-inducible factors (HIFs) expression also increases with mechanical stretch, this study tested whether upregulation of HIFs is an intermediary mechanism linking prolonged vein wall stretch to the changes in MMP expression and venous contraction.Methods: Segments of rat inferior vena cava (IVC) were suspended in tissue bath under 0.5-g basal tension for 1 hour, and a control contraction to phenylephrine (PHE, 10(-5)M) and KCl (96mM) was elicited. The veins were then exposed to prolonged 18 hours of tension at 0.5 g, 2 g, 2 g plus HIF inhibitor U0126 (10(-5)M), 17-[2-(dimethylamino)ethyl] amino-17-desmethoxygeldanamycin (17-DMAG, 10(-5)M), or echinomycin (10(-6)M), or 2 g plus dimethyloxallyl glycine (DMOG; 10(-4)M), a prolyl-hydroxylase inhibitor that stabilizes HIF. The fold-change in PHE and KCl contraction was compared with the control contraction at 0.5-g tension for 1 hour. Vein tissue homogenates were analyzed for HIF-1 alpha, HIF-2 alpha, MMF-2, and MMP-9 messenger RNA (mRNA) and protein amount using real-time reverse transcription polymerase chain reaction and Western blots.Results: Compared with control IVC contraction at 0.5-g tension for 1 hour, the PHE and KCl contraction after prolonged 0.5-g tension was 2.0 +/- 0.35 and 1.1 +/- 0.06, respectively. Vein contraction to PHE and KCl after prolonged 2-g tension was significantly reduced (0.87 +/- 0.13 and 0.72 +/- 0.05, respectively). PHE-induced contraction was restored in IVC exposed to prolonged 2-g tension plus the HIF inhibitor U0126 (1.38 +/- 0.15) or echinomycin (1.99 +/- 0.40). U0126 and echinomycin also restored KCl-induced contraction in NC exposed to prolonged 2-g tension (1.14 +/- 0.05 and 1.11 +/- 0.15, respectively). Treatment with DMOG further reduced PHE- and KCl-induced contraction in veins subjected to prolonged 2-g tension (0.47 +/- 0.06 and 0.57 +/- 0.01, respectively). HIF-1 alpha and HIF-2 alpha inRNA were overexpressed in NC exposed to prolonged 2-g tension, and the overexpression was reversed by U0126. The overexpression of HIF-1 alpha and HIF-2 alpha in stretched NC was associated with increased MMP-2 and MMP-9 mRNA. The protein amount of HIf-1 alpha, HIF-2 alpha, MMP-2, and MMP-9 was also increased in NC exposed to prolonged 2-g wall tension.Conclusions:Prolonged increases in vein wall tension are associated with overexpression of HIF-1 alpha and HIF-2 alpha, increased MMP-2 and MMP-9 expression, and reduced venous contraction in rat IVC. Together with our report that MMP-2 and MMP-9 inhibit NC contraction, the data suggest that increased vein wall tension induces HIF overexpression and causes an increase in MMP expression and reduction of venous contraction, leading to progressive venous dilation and varicose vein formation. (J Vase Surg 2011;53:764-73.)