Chen Y, Bornfeldt K E, Arner A, Jennische E, Malmqvist U, Uvelius B, Arnqvist H J
Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden.
Am J Physiol. 1994 Feb;266(2 Pt 1):E224-9. doi: 10.1152/ajpendo.1994.266.2.E224.
The present study focuses on the role of the insulin-like growth factor (IGF) system in the development of smooth muscle hypertrophy. Hypertrophy was initiated by partial ligation of portal vein or urethra in female Sprague-Dawley rats weighing approximately 220 g. Levels of mRNA were analyzed by solution hybridization. Seven days after ligation, the wet weight of the portal vein was increased about threefold and the concentration of IGF-I mRNA was increased fourfold. The bladder wet weight was increased twofold 3 days after ligation and fourfold 10 days after ligation. IGF-I mRNA in the bladder was elevated 3-fold after 3 days and 2.5-fold after 10 days, whereas IGF binding protein 2 mRNA was increased approximately 2-fold after 3 days and 5-fold after 10 days. IGF-I receptor mRNA in the hypertrophying bladder remained unchanged. Increased levels of IGF-I were demonstrated with immunohistochemistry in both hypertrophying portal vein and urinary bladder. The results show a specific increase in IGF-I mRNA as well as an increased IGF-I immunoreactivity during hypertrophy of smooth muscle, which suggests that the local IGF-system may play a role in smooth muscle hypertrophy.
本研究聚焦于胰岛素样生长因子（IGF）系统在平滑肌肥大发展过程中的作用。通过对体重约220 g的雌性斯普拉格-道利大鼠的门静脉或尿道进行部分结扎来引发肥大。采用溶液杂交法分析mRNA水平。结扎7天后，门静脉湿重增加约3倍，IGF-I mRNA浓度增加4倍。结扎3天后膀胱湿重增加2倍，结扎10天后增加4倍。膀胱中的IGF-I mRNA在3天后升高3倍，10天后升高2.5倍，而IGF结合蛋白2 mRNA在3天后增加约2倍，10天后增加5倍。肥大膀胱中的IGF-I受体mRNA保持不变。免疫组织化学显示，在肥大的门静脉和膀胱中IGF-I水平均升高。结果表明，在平滑肌肥大过程中IGF-I mRNA特异性增加以及IGF-I免疫反应性增强，这表明局部IGF系统可能在平滑肌肥大中发挥作用。
