Histopathological characteristics of renal changes in human renin-angiotensinogen double transgenic rats

The human renin-angiotensinogen double transgenic rat (dTGR) is a model of hypertension. The aim of this short report was to describe the histopathological characteristics of the renal changes in this rat strain in detail. Seven to nine-week-old male dTGRs were euthanized, and their kidneys were histopathologically examined. At the time of sacrifice, the average systolic blood pressure of the dTGRs was 258 mmHg, while that of age-matched, normal Sprague-Dawley rats was 135 mmHg. In the kidney, histopathological changes were observed mainly in blood vessels, tubules and glomeruli. In blood vessels, changes including medial hypertrophy, intimal thickening, hyaline change and/or fibrinoid necrosis were observed in arteries and arterioles. In tubules, changes including tubular basophilia were observed radially, mainly around interlobular arteries with lesions. In glomeruli, changes including hyaline droplet accumulation in podocytes, which was accompanied by increased expression of desmin, were observed. These changes were similar to those reported in other hypertension models, such as the spontaneously hypertensive rat (SHR). We hope that this short report will be helpful in histopathological examination of renal changes in this or other hypertension models.