Is mechanically induced cystic endometrial hyperplasia (CEH) a suitable model for study of spontaneously occurring CEH in the uterus of the bitch?

CONTENTS: Cystic endometrial hyperplasia (CEH) was experimentally reproduced by the intraluminal insertion of a silk wire in the uterus of metestral bitches to obtain a model for the study of spontaneously occurring CEH in the bitch. This mechanically reproduced CEH corresponded histologically very well to spontaneously occurring CEH. With respect to sex hormone receptor expressions, however, there was no similarity. In the mechanically induced CEH, progesterone receptor expression was reduced in the epithelial cells (surface epithelium and endometrial glands) and slightly increased in the stromal fibroblasts and myometrium as compared with the normal metestrus uterus. The oestrogen receptor expression in mechanically induced CEH was reduced in the epithelial cells (surface epithelium and endometrial glands) and more or less unchanged in the stromal fibroblast and myometrium as compared with the normal metestrus uterus. This is in contrast to the increased sex hormone receptor expressions in all uterine cell types, observed in spontaneously occurring CEH. The mechanically induced CEH model corresponds immunohistochemically more to early placentation and to pyometra in the bitch. Thus this experimental CEH model is not suitable for pathogenic studies of spontaneously occurring CEH in the bitch.