HE. 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. Keywords: hypertension, kidney, histopathology, human renin-angiotensinogen double transgenic rat In humans, hypertension causes end-organ damage, especially in the kidney. Similar end-organ damage is also observed in animal models of hypertension, and these models are widely used to investigate the pathogenesis or therapeutics1. The human renin-angiotensinogen double transgenic rat (dTGR) is a model of hypertension. This model overexpresses human renin and angiotensinogen, which results in increase of angiotensin II, and develops accelerated hypertension leading to marked damage of the kidney2. Though there have been several reports of renal changes in the dTGR2, 3, 4, the histopathological characteristics of the renal changes have not been fully described. The aim of this short report was to describe the histopathological characteristics of the renal changes in this rat strain in more detail. Animal usage was approved by the Institutional Animal Care and Use Committee of Sumitomo Dainippon Pharma Co., Ltd. Five male dTGRs were prepared by cross-breeding two single-transgenic rat lines supplied by the Max Delbrck Center (Berlin, Germany) that which overexpress the genes for human renin (hREN) and human angiotensinogen (hAOGEN), respectively. The rats were fed commercial chow diet (CE-2; CLEA Japan, Inc. ) and tap waterad libitum. From 6 weeks old, systolic blood pressure was measured by tail-cuff method, and urinary albumin and creatinine were measured by automated biochemistry analyzer (JCA-BM1650, JEOL, Tokyo, Japan) once a week. The animals were euthanized by exsanguination under isoflurane anesthesia at 7 or 8 weeks old when they showed poor AMG-333 conditions or otherwise at 9 weeks old. For histopathology, unilateral kidneys were excised and fixed in 10% Rabbit Polyclonal to OR2T10 neutral buffered formalin, embedded in paraffin, sectioned and stained with hematoxylin and eosin (HE). In addition , sections of the kidney were stained by the periodic acid-Schiff (PAS) method and periodic acid-methenamine silver (PAM) method. Furthermore, sections of the kidney were subjected to immunohistochemistry (IHC) using a labeled polymer method with Histofine Simple Stain Rat MAX-PO (MULTI) (Nichirei Biosciences Inc., Tokyo, Japan). Table 1shows the primary antibodies that were used in this study. == Table 1 . Antibodies Used in this Study. == For comparison with the dTGRs, five 7-week-old normal male Sprague-Dawley (SD) rats were treated and examined in the same manner as the dTGRs and sacrificed at 9 weeks old. Systolic blood pressure was high in the dTGRs from 6 weeks old, and at the time of sacrifice, it was 254 12 mmHg in the dTGRs and 135 14 mmHg in the normal SD rats (the numbers represent the group mean and standard deviation, respectively). Also, the urinary albumin/creatinine ratio was high in the dTGRs from 6 weeks old, and at the time of sacrifice, it was 8. 9 5. 6 mg/mg in the dTGRs and 0. 0 0. 0 mg/mg in the normal SD rats. In the kidney, histopathological changes were observed mainly in blood vessels, tubules and glomeruli. The changes in each unit are described as follows. In blood vessels, medial hypertrophy was observed diffusely from interlobar arteries to efferent/afferent arterioles (Figs. 1A, B). From interlobar to arcuate arteries, minimal infiltration of inflammatory cells in the intima and focal degeneration of media were AMG-333 occasionally observed (Fig. 1A). In addition , from arcuate arteries to efferent/afferent arterioles, a AMG-333 minimal increase in fibroblasts was observed in the adventitia or surrounding interstitium in a few vessels (Fig. 1A). From the interlobular artery to efferent/afferent arterioles, focal intimal thickening, which was accompanied by rupture and/or duplication of the internal elastic lamina (Figs. 1B, C), and hyaline change and/or fibrinoid necrosis of the media were observed in many vessels (Figs. 1D, G). The blood vessels with hyaline changes and/or fibrinoid necrosis were positive for PAS and albumin (Figs. 1E, F). In the vessel wall membrane of the infected efferent/afferent arterioles, PAM-positive lentigo were found (Fig. 1H), as noticed in normal afferent arterioles. == Fig. 1 ) == Histopathological changes in arteries and. (A) A great arcuate artery. In the intima, minimal infiltration of inflammatory cells is seen. In the your data, hypertrophy and focal deterioration (arrow) is seen. In the adventitia or associated with interstitium, nominal increase of fibroblasts is seen. HE. (B) An interlobular artery. Key intimal thickening can be seen (arrows), along with medial hypertrophy. HE. (C) The same discipline as in (B) observed within fluorescent microscopic lense. Rupture (arrow) and replication (arrowhead) within the.