Carey A V, Carey R M, Gomez R A
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville 22908.
Hypertension. 1992 Feb;19(2 Suppl):II168-75. doi: 10.1161/01.hyp.19.2_suppl.ii168.
To determine whether alpha-smooth muscle (alpha-SM) isoactin is expressed in the maturing kidney as well as the changes associated with maturation, we processed for immunocytochemistry kidney sections from Wistar-Kyoto rats at various prenatal (15, 17, 19, and 20 days) and postnatal (2, 5, 10, 15, and 90 days) ages using a monoclonal anti-alpha-SM actin antibody. At 15 days of gestation, only a few mesenchymal cells contained alpha-SM actin. However, other fetal vasculature structures (heart, aorta, peripheral blood vessels) expressed alpha-SM actin. Vascular localization was first observed at 17 days of gestation in larger corticomedullary vessels. As maturation progressed, actin expression accompanied the outward growth and branching of the kidney vasculature. During fetal life (17 days), alpha-SM actin also was expressed within juxtamedullary glomeruli. As the centrifugal maturation of nephrons proceeded, intraglomerular expression extended to outer cortical glomeruli. After 10 days of postnatal life, once glomerular development was completed, intraglomerular expression was no longer present. Peritubular capillaries expressed alpha-SM actin during early (fetal and neonatal) development, but not in the adult kidney. We conclude that 1) expression of alpha-SM actin in the developing kidney is delayed with respect to other vascular beds, 2) expression of alpha-SM actin follows the centrifugal pattern of nephrovascular development, and 3) glomerular and peritubular capillary expression of alpha-SM actin is a transient developmental phenomenon associated with active glomerulogenesis and capillary growth.
为了确定α-平滑肌（α-SM）肌动蛋白异构体是否在成熟肾脏中表达以及与成熟相关的变化，我们使用单克隆抗α-SM肌动蛋白抗体，对不同产前（15、17、19和20天）和产后（2、5、10、15和90天）龄期的Wistar-Kyoto大鼠肾脏切片进行免疫细胞化学处理。在妊娠15天时，只有少数间充质细胞含有α-SM肌动蛋白。然而，其他胎儿血管结构（心脏、主动脉、外周血管）表达α-SM肌动蛋白。在妊娠17天时，首次在较大的皮质髓质血管中观察到血管定位。随着成熟进程的推进，肌动蛋白表达伴随着肾脏血管向外生长和分支。在胎儿期（17天），α-SM肌动蛋白也在近髓肾小球内表达。随着肾单位离心性成熟的进行，肾小球内表达扩展到外皮质肾小球。出生后10天，一旦肾小球发育完成，肾小球内表达就不再存在。肾小管周围毛细血管在早期（胎儿期和新生儿期）发育过程中表达α-SM肌动蛋白，但在成年肾脏中不表达。我们得出结论：1）发育中的肾脏中α-SM肌动蛋白的表达相对于其他血管床延迟；2）α-SM肌动蛋白的表达遵循肾血管发育的离心模式；3）α-SM肌动蛋白在肾小球和肾小管周围毛细血管的表达是一种与活跃的肾小球发生和毛细血管生长相关的短暂发育现象。
