The role of transforming growth factor beta in cervical remodeling within the rat cervix.

OBJECTIVE

Transforming growth factor beta (TGFbeta) plays a central role in extracellular matrix remodeling. We hypothesized that TGFbeta signaling is involved in cervical remodeling. This study evaluated patterns within this signaling pathway.

STUDY

DESIGN

The cervices of nonpregnant and timed pregnant rats were obtained. Messenger ribonucleic acid (mRNA) expression of TGFbeta1, TGFbeta receptor 1 (TbetaR1), TbetaR2, and TbetaR3 was evaluated. Four animals were euthanized for each time point. Western blotting was performed for protein expression. Phosphorylated mothers against decapentaplegic (Smad)-2 and -3 phosphorylation was assessed to evaluate TGFbeta activation.

RESULTS

TGFbeta1 mRNA increased through day 21 and declined on day 22 (analysis of variance, P = .001). TbetaR1 expression was unchanged. TbetaR2 and TbetaR3 mRNA expression was similar to TGFbeta1. TbetaR3 protein expression was similar to mRNA. Smad2 phosphorylation paralleled changes in TbetaR3.

CONCLUSION

Components of the TGFbeta signaling pathway increase during pregnancy along with Smad2 activation. The decline on day 22 correlates with a transition to the ripening phase supporting a role in cervical remodeling.