地塞米松、甲状腺素对大鼠胎肺表面活性物质影响及机制的初步研究

THE PRELIMINARY STUDY OF EFFECTS AND MECHNISM OF DEXAMETHASONE AND THYROXINE ON PULMONARY SUEFACTANT OF RAT FETAL LUNG EXPLANTS

本文用大鼠胎肺组织块无血清培养观察地塞米松（Ｄｅｘ）、甲状腺素（Ｔ＿４）对大鼠胎肺表面活性物质（ＰＳ）的作用特点。Ｄｅｘ效应在胚胎１８、１９天最显著，并随Ｄｅｘ浓度增加而增高，但高浓度Ｄｅｘ对胎肺糖皮质激素受体（ＧＣＲ）有向下调节作用。Ｔ＿４可促进ＰＳ增加，并与Ｄｅｘ有协同作用，对胎肺ＧＣＲ有向上调节作用。本文为临床合理应用Ｄｅｘ或联合Ｔ＿４预防新生儿呼吸窘迫综合征提供实验基础。

he effects of dexamethasone and thyroxine on the pulmonary surfactant of fetalrat lung explants were studied in vitro. It mainly occured in 18 or 19 days of rat ges-tational age that the maturation of pulmonary surfactant of the lung explants was sti- mulated by dexamethasone.The effects of dexamethasone were also dose-dependent. Butthe specifc binding of cytoplasmic glucocorticoid recepter of 18 days fetal rat lungcxplants was decreased according to the increased concentration of dexamethasone(down- regulation).Thyroxine also inereased the pulmonary surfactant,and the pulmonary sur- factant was increased,being treated dy both dexamethasone and thyroxine,more thaneither alone.At least in part.this might be caused by the up-regulation of thyroxineon glucocorticoid recepter.