Chen Y, Arner A, Bornfeldt K E, Uvelius B, Arnqvist H J
Department of Cellbiology, Faculty of Health Sciences, University of Linköping, Sweden.
Growth Regul. 1995 Mar;5(1):45-52.
The aim of the present investigation was to study the role of the IGF system in the development of smooth muscle hypertrophy. Hypertrophy was initiated by partial ligation of the urethra in female Sprague-Dawley rats. The solution hybridization assay was used to analyse the mRNA levels. Ligation of the urethra induced a sustained increase in bladder wet weight during the following 6-week period studied. IGF-I mRNA increased from 1 to 3 amol/micrograms DNA 1-day after ligation, peaked at 3-days (4-fold), and normalized 6-weeks after ligation. In hypertrophying bladder, IGFBP-2 and -4 mRNA increased sharply during the first 10 days (5-fold) and remained elevated during the 6-week period. The IGF-I receptor mRNA did not change significantly. Removal of the obstruction 10 days after ligation caused a regression of bladder wet weight, and resulted in normalization of IGF-I, IGFBP-2 and -4 mRNA. The results show a close correlation between progression or regression of smooth muscle hypertrophy and differential regulation of IGF-I, IGFBP-2 and -4 mRNA, indicating that the IGF system may play a role in smooth muscle hypertrophy.
本研究的目的是探讨胰岛素样生长因子（IGF）系统在平滑肌肥大发展过程中的作用。通过对雌性斯普拉格-道利大鼠尿道进行部分结扎来诱导肥大。采用溶液杂交分析法分析mRNA水平。在接下来研究的6周内，尿道结扎导致膀胱湿重持续增加。结扎后1天，IGF-I mRNA从1 amol/μg DNA增加到3 amol/μg DNA，在第3天达到峰值（增加4倍），并在结扎后6周恢复正常。在肥大的膀胱中，IGFBP-2和-4 mRNA在最初10天内急剧增加（增加5倍），并在6周内持续升高。IGF-I受体mRNA没有显著变化。结扎后10天解除梗阻导致膀胱湿重减轻，并使IGF-I、IGFBP-2和-4 mRNA恢复正常。结果表明，平滑肌肥大的进展或消退与IGF-I、IGFBP-2和-4 mRNA的差异调节密切相关，提示IGF系统可能在平滑肌肥大中发挥作用。
