缺氧诱导大鼠肺动脉PDGF和c－myc基因表达增强

为了研究生长因子和原癌基因在缺氧所致肺血管结构重建中的作用，我们选用Ｗｉｓｔａｒ大鼠，置于低压仓内模拟海拔５０００米高度持续缺氧７天和１４天。与平原对照组相比，缺氧７天时肺动脉血小板源生长因子Ａ链（ＰＤＧＦ－Ａ）基因表达水平略有升高，而后有下降趋势；缺氧１４天时ＰＤＧＦ－Ｂ链３．５ｋｂｍＲＮＡ表达显著升高。点杂交结果显示：ｃ－ｍｙｃ原癌基因正常时表达水平很低。Ｎｏｒｔｈｅｒｎｂｌｏｔ可见缺氧７天时有２．２ｋｂｍＲＮＡ转录，缺氧１４天时其含量进一步增加为正常的６倍。结果表明，缺氧过程中，ＰＤＧＦ－Ａ链和Ｂ链是顺序表达的，其表达水平与缺氧性肺血管结构重组过程有一定相关。ＰＤＧＦ的促增殖作用是通过ｃ－ｍｙｃ基因产物实现的。

Increased Expression of PDGF and c-myc Genes in Pulmonary Artery in Hypoxic Rat

o study the molecular basis of hypoxia pulmonary remodeling we developed a model in which male Wistar rats were exposed to hypoxia for 0,7 and 14 daysrespectively.Northern blot analysis revealed that PDGF-B chain mRNA in pulmona-ry arteries at day 14 was increased,whereas PDGF-A chain mRNA levels reacheda maximum on day 7 and then declined, Thus the increase in the PDGF-A chainmRNA Ievel occurred before that in the PDGF-B chain mRNA Ievel.During hypo-cixe xpoure,c-myc proto-oncogene mRNA Ievel changed rapidly, The c-myc mRNAincreased by 6-fold at day 14.These result,shoved that PDGF-A and-B chainsqiuseentially involved in hypoxic pulmonary vaoscular remodeling,The c-myc geneproduct is an intracellular mediator of the growth response to PDGF.