IN-VITRO MODEL OF UTERINE LEIOMYOMAS - FORMATION OF BALL-LIKE AGGREGATES

To clarify the biological characteristics of uterine leiomyomas, cells explanted and cultured from uterine leiomyomas and from normal myomet rial tissue were observed by time-lapse cinemicrography and phase-cont rast microscopy. The histological characteristics were evaluated by el ectron microscopy and immunofluorescence microscopy, and these observa tions revealed significant differences, By time-lapse cinemicrography, the cells cultured from leiomyomas and myometrium differed in their b ehaviour. Cells from the myometrium started to grow in parallel with t he cell's major axis and formed topographically uniform hills and vall eys by day 21 of culture, In contrast, the cells from leiomyomas start ed to grow irregularly, as if having no contact inhibition, and formed ball-like aggregates of cells by day 21 of culture. The aggregates re sembled the nodules of leiomyoma in vivo, Ultrastructurally, cells fro m both leiomyomas and myometrium had typical features of smooth muscle . Immunofluorescently, a different distribution of a-smooth muscle act in-positive filaments and different staining of cellular fibronectin a nd N-cadherin between the cells from leiomyomas and myometrium were ob served, which may contribute in part to the different behaviour of the cells, Given that the explant cell culture system resembles the featu res of uterine leiomyomas in vivo, this suggests that it can be used a s an in-vitro model.