RESUMO
<p><b>OBJECTIVE</b>To study the histomorphological and immunochemical characteristics of benign prostate hyperplasia (BPH) induced by urogenital sinus (UGS) implantation in the rat model.</p><p><b>METHODS</b>We randomized 32 seven-week old male SD rats into a sham operation control and three (2-, 3- and 6-week) UGS model groups. We made the UGS model by implanting two urogenital sinuses from homogeneous male rat embryos into the host rats' right anterior lobe, and killed the model rats 2, 3 and 6 weeks later for measuring the wet weight, volume and micromorphological parameters of the right anterior lobe and detecting the factors expressed in the epithelium, stroma and smooth muscle by immunochemistry.</p><p><b>RESULTS</b>The model rats showed significant increases in the wet weight, volume and relevant indexes of the right anterior lobe (P < 0.05), as well as in the proportion of stromal area and relative stromal volume (P < 0.1) with the prolonging of time. The mean stromal proportion of the 3-week models was as high as 75.32%. There was also a time-dependent increase in the relative total volume of epithelia in the model groups. The luminal area and the proportions of the luminal and epithelial volumes were obviously reduced in the model rats as compared with the sham operation controls. Pan-cytokeratin positive particles were located in epithelial cells, vimentins abundantly expressed in mesenchymocytes, and alpha-smooth muscle actins expressed around the lumen of the gland.</p><p><b>CONCLUSION</b>BPH induced by urogenital sinus implantation in rats is typically stromal hyperplasia, and the locations of related factors are similar to those in men with BPH.</p>