Differential collagen expression in kidney and heart during hypertension

The aim of the present study was to investigate the immunohistochemical expression of selected collagen types, namely collagen types I and V and procollagen type III in the renal parenchyma and interstitium and in the myocardium of spontaneously hypertensive rats. For the present study, we used two age groups of 6- and 12-month-old spontaneously hypertensive rats. An immunohistochemical analysis was conducted with monoclonal antibodies against collagen types I and V and procollagen type III. A semi-quantitative analysis of immunostaining intensity was conducted with the Image J software. In the kidney, all three molecules showed higher expression at the age of 12 months, which was particularly notable for procollagen type III and collagen type V, which stained as highly-positive. In the myocardium, the immunoreactivity of collagen types I and V was stronger in 12-month-old animals, while that of procollagen type III did not change substantially. The present study suggests a role of collagen types III and V in hypertensive kidney disease, while also establishing the role of increased expression of collagen types I and V in adverse myocardial remodeling (Tab. 1, Fig. 2, Ref. 48).