Cyclic expression of mRNA transcripts for connective tissue components in the mouse ovary

In the ovary, differentiation of germinal cells into primordial follicles, functional ovulatory follicles and corpus luteum, all take place in a conne ctive tissue matrix. We postulated that extracellular matrix (ECM) of the o vary participates actively in ovarian functions. To test this, the mRNA lev els for several ECM components were determined in the mouse ovary at six di stinct stages of the 4-day oestrous cycle. Northern analysis revealed stati stically significant cyclic expression patterns for the mRNAs coding for ty pe III, IV and VI collagens as well as for the small proteoglycan, biglycan , and for syndecan-1 and osteonectin. The cyclic changes observed in the mR NAs for these structural components exceeded those for matrix metalloprotei nases (MMP)-2, -9 and -13, and for tissue inhibitors of matrix metalloprote inases (TIMP)-1, -2 and -3, where the changes were not statistically signif icant, despite their apparent role in ECM remodelling in the ovary. These o bservations support the hypothesis that cyclic changes in the production an d degradation of ECM are part of normal ovarian function connected with fol licular maturation, rupture and corpus luteum formation.