链霉素对缺氧大鼠右心室肥大及C－myc原癌基因表达的影响

本文观察了非选择性阳离子通道阻断剂链霉素（在脊椎动物心肌阻断牵张激活的钠离子跨膜内流）对缺氧大鼠右心室肥大和缺氧大鼠心肌中ｃ─ｍｙｃ基因表达的影响。结果如下：（１）急性缺氧时，右心室收缩压明显增高，慢性间断性缺氧进一步增高右心室收缩压并明显增高右心室重量指数。（２）链霉素对急性缺氧性肺动脉增压反应无影响，但可明显降低慢性缺氧大鼠右心室收缩压和右心室重量指数。（３）缺氧引起右室心肌迅速一过性的ｃ－ｍｙｃ基因表达增强，链霉素可降低ｃ－ｍｙｃ表达水平。提示Ｎａ内流和Ｃ－ｍｙｃ表达可能参与了缺氧性右心室肥大的发生。

EFFECTS OF STREPTOMYCIN ON HYPOXIC RIGHT VENTRICULAR HYPERTROPHY AND C-MYCPROTOONCOGENE EXPRESSION IN MYOCARDIUM OF HYPOXIC RATS

o study the roles of sodiui11 influx and proto-oncogene c-myc in thepathogenesis of hypoxic right ventricular hypertrophy, we observed the expre-ssion of c-myc in myocardium of hypoxic rats and the preventive effect ofstreptomycin(a blocker of stretch-activated sodium influx) on hypoxic car-diac hypertrophy. Results obtained were as following:acute hypoxia resultedin an increase of right ventricular systolic pressure, Chronic intermittenthypoxia further augmented the right ventricular systolic pressure and elevatedright ventricular weight/body weight ratio. Streptomycin did not affectacute hypoxic pressor response but did reduce right ventricular systolic pre-ssure and right ventricular weight/body weight ratio in chronic hypoxic rats.After 30 minutes of hypoxia,a strong but transient expression of c-myc wasobserved in right ventricular myocardium,streptomyocin decreased the exp-ression of c-myc, These results suggested that sodium influx and c-myc ex-pression may participate in the pathogenesis of hypoxic right ventricularhypertrophy.