Transforming Growth Factor-β1 Expression and Phenotypic Modulation in the Kidney of Hypertensive Rats

Abstract

We have previously reported that renal mRNA levels for transforming growth factor-β1, fibronectin, and collagens were increased in 32-week-old stroke-prone spontaneously hypertensive rats (SHRSP) with severe nephrosclerosis. To elucidate the mechanism of hypertension-induced nephrosclerosis, we examined gene expression and localization of transforming growth factor-β1 and cellular phenotype in the kidney of 25-week-old SHRSP with moderate renal damage. Renal mRNA was measured by Northern blot analysis. The localization of transforming growth factor-β1 and cellular phenotype was determined by immunohistochemistry. In the kidney of 25-week-old SHRSP, renal transforming growth factor-β1 mRNA was elevated compared with Wistar-Kyoto rats (WKY), whereas renal collagen mRNAs of SHRSP were not increased. Immunoreactive transforming growth factor-β1 in SHRSP was mainly localized in glomerular cells. Furthermore, α-smooth muscle actin and desmin were significantly expressed in SHRSP glomerular cells, in co...