Leuprolide acetate-treated leiomyomas retain their relative overexpression of collagen type I and collagen type III messenger ribonucleic acid

OBJECTIVE: To evaluate the levels of mRNA for the extracellular matrix proteins collagen type I, collagen type III, and fibronectin in leiomyomas and myometrium obtained from women treated with GnRH-agonist (GnRH-a) and to examine steroid hormone regulation of these proteins using an in vitro explant culture system. METHODS: Northern blot analysis of mRNA was obtained from hysterectomy specimens at the time of surgery or after 48 hours of in vitro steroid treatment. A portion of the tissue was processed for RNA, and the remaining tissue was used to establish explant cultures. Extracellular matrix/α-tubulin ratio was computed for each band, and within each experiment the lowest ratio was standardized to a value of one densitometry unit to allow for comparison among experiments. RESULTS: There is a relative overexpression of both collagen type I and collagen type III mRNAs but not fibronectin in leiomyomas compared to myometrium from the same uteri of women treated with GnRH-a. CONCLUSION: Leiomyomas obtained from women treated with GnRH-a show an up-regulation of collagens type I and type III similar to that seen in leiomyomas obtained from women in the proliferative phase of their menstrual cycles.