Leiomyomas, which are the commonest pelvic tumors in women, are originated from myometrial cells. Although the exact initial pathophysiologic event of the leiomyoma is not known, recent evidences suggested that the effects of sex steroid hormones in the process of tumor growth are mediated by local production of growth factors including epidermal growth factor(EGF), insulin-like growth factor-I(IGF-I) and insulin-like growth factor-II(IGF-II). Recently, it was suggested that transforming growth factor-beta(TGF-beta) may play a role for growing of leiomyomas. It was known that TGF-beta increase the formation of extracellular matrix. And we examined TGF-beta1 expression and tried to know the effect of TGF-beta1 on the extracellular matrix, collagen I and III mRNA levels in cultured leiomyoma and myometrial cells. We found that immunoreactive TGF-beta1 was expressed in myometriums and in leiomyomas. There was no difference at the intensity of immunostaining between two tissues. In northern blotting, there was no difference of TGF-beta1 expression at the transcriptional level in both tissues. TGF-beta1 increased the mRNA levels of collagen I in cultured myometrial and leiomyoma cells at the concentration of 1 ng/ml(p<0.05), 10 ng/ml(p<0.001). And TGF-beta1 increased the mRNA levels of collagen III in cultured myometrial and leiomyoma cells at the concentration of 1 ng/ml (p<0.05), 10 ng/ml(p<0.05). Therefore, expressed TGF-beta1 may stimulate the incorporation of collagen I and III into the extracellular matrix in myometriums and leiomyomas.
Animals ; Blotting, Northern ; Collagen* ; Extracellular Matrix ; Female ; Gonadal Steroid Hormones ; Humans ; Intercellular Signaling Peptides and Proteins ; Leiomyoma* ; Mice ; Myometrium* ; RNA* ; RNA, Messenger ; Transforming Growth Factor beta ; Transforming Growth Factor beta1*