Animal Models of Human Disease

Comparative Pathobiology Group

One animal model of human uterine disease that we've assessed is diethylstilbestrol (DES)-induced uterine leiomyomas. In the past, the focus has been mainly on DES-induced epithelial lesions, particularly vaginal adenosis and adenocarcinoma; however, uterine smooth muscle cells are also recognized as cellular targets of DES.

We have found uterine leiomyomas that occur in mice following exposure to DES prenatally on days 9-16 of gestation or on neonatal days 1-5. These DES-induced leiomyomas have typical gross and histomorphologic characteristics of spontaneously occurring smooth muscle tumors of B6C3F1 mice previously described in our laboratory, and they are also similar to those observed in women.

We are also assessing the utility of the potbellied pig as a model for spontaneously occurring uterine leiomyomas. Unlike commercially-raised hogs, potbellied pigs provide an aging population, with the life span estimated to be as long as 20-25 years, with an average of 10-15 years. Many female pet pigs are neither spayed nor bred. As a result, intact potbellied pig females are subject to cyclic hormonal influences about every 21 days, somewhat approximating the year-round cyclic hormonal influences of the menstrual cycle in women.

The potbellied pig appears to have a high incidence of spontaneous uterine leiomyomas, previously unrecognized due to the low density and scattered distribution of pet pigs. Studies are underway to understand the biological relevance of these tumors to fibroids found in women.