Resumen de Tenascin expression during the postnatal development of mesangium in murine kidneys
It is now widely acknowledged that extracellular matrix (ECM) activates predetermined developmental programs to induce the differentiation of epithelial cells. Tenascin (TN) is an ECM glycoprotein that plays a role in mediating cell-matrix adhesion. In mature mammalian kidneys TN is an important component of mesangial matrix. However, its time course and spatial patterns of expression during renal corpuscle morphogenesis have not been established. This study used immunohistochemistry to examine TN expression during the postnatal development of mesangium in the renal corpuscle of murine kidneys. Four different stages of renal corpuscle development were considered: S-shaped body, developing loop capillary, maturing renal corpuscle, and mature renal corpuscle. In the developing capillary stage, TN expression began in the mesangium, and in this stage TN immunoreactivity was also seen in the hilus of the renal corpuscle. High levels of TN expression were observed in both the mesangium and the ECM of the afferent and efferent arterioles in the maturing and mature renal corpuscle stages. The present results show that the first appearance of mesangial cells and the beginning of TN reactivity in the mesangial ECM are concomitant processes, which suggests that TN reactivity may constitute a useful marker to study the development and maturation of mesangium.
