The three objectives of this proposal will examine the regulation of both growth and softening of the cervix during pregnancy. In the rat, cervical growth is accompanied by an accumulation of epithelial and stromal cells. The first objective is to determine the influence of relaxin, estrogen and progesterone on the rates of apoptosis and proliferation of cervical cells. At three-day intervals throughout the second half of pregnancy, relaxin's action will be neutralized with a monoclonal antibody for rat relaxin, estrogen's action will be blocked with the estrogen antagonist ICI 182,780, and progesterone's action will be blocked with the progesterone antagonist RU 486. The rates of apoptosis will be determined immunohistochemically by employing the terminal deoxynucleotidyl transferase-mediated UTP end-labeling (TUNEL) method. Electron microscopy will be used to evaluate treatment effects on percent of cell types undergoing apoptosis, stromal collagen, and epithelium functional complexes. Light microscopy immunohistochemistry will be used also to evaluate treatment effects on epithelium functional complexes. Rates of cell proliferation will be determined immunohistochemically by measuring the rate of incorporation of 5-bromo-2-deoxyuridine (BrdU) into proliferating cells and also by measuring the expression of proliferating cell nuclear antigen (PCNA). RU 486 induces delivery and promotes cervical softening at term in women and other species. The second objective will test the hypothesis that relaxin is more effective than RU 486 in promoting cervical softening near term. To accomplish this, the effects of RU 486 and relaxin on cervical extensibility will be determined at term in relaxin-deficient rats in which endogenous relaxin is immunoneutralized throughout the second half of pregnancy. Morphometric analysis will also be done to compare the effects of RU 486 and relaxin on the histological characteristics of the cervix. This proposal will also examine a novel procedure for both inducing delivery and softening the cervix. Induction of labor more than doubled to 19% between 1989 and 1998. The success of labor induction is influenced by the state of the cervix. The active component of the two approved agents for cervical softening (Prepidil and Cervidil) is PGE2, and this prostaglandin causes uterine hyperstimulation in a significant percentage of patients. Relaxin has potential advantages over PGE2 because relaxin not only promotes rapid and marked growth and softening of the cervix, but also reduces uterine contractility. The third objective will test the hypothesis that the administration of RU 486 for induction of delivery in combination with relaxin for induction of cervical softening is more effective in promoting rapid and safe delivery in pregnant rats than is the administration of RU 486 alone. Treatment with RU 486 alone and in combination with exogenous relaxin will be done at term with relaxin-deficient rats.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD040448-04
Application #
6873021
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Program Officer
Ilekis, John V
Project Start
2002-04-01
Project End
2007-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
4
Fiscal Year
2005
Total Cost
$237,648
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Physiology
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Yao, Lijuan; Cooke, Paul S; Meling, Daryl D et al. (2010) The effect of relaxin on cell proliferation in mouse cervix requires estrogen receptor {alpha} binding to estrogen response elements in stromal cells. Endocrinology 151:2811-8
Yao, Lijuan; Agoulnik, Alexander I; Cooke, Paul S et al. (2009) Relative roles of the epithelial and stromal tissue compartment(s) in mediating the actions of relaxin and estrogen on cell proliferation and apoptosis in the mouse lower reproductive tract. Ann N Y Acad Sci 1160:121-9
Yao, LiJuan; Agoulnik, Alexander I; Cooke, Paul S et al. (2008) Relaxin acts on stromal cells to promote epithelial and stromal proliferation and inhibit apoptosis in the mouse cervix and vagina. Endocrinology 149:2072-9
Lee, Hyung-Yul; Zhao, Shuangping; Fields, P A et al. (2005) Clinical use of relaxin to facilitate birth: reasons for investigating the premise. Ann N Y Acad Sci 1041:351-66
Lee, Hyung-Yul; Sherwood, O David (2005) The effects of blocking the actions of estrogen and progesterone on the rates of proliferation and apoptosis of cervical epithelial and stromal cells during the second half of pregnancy in rats. Biol Reprod 73:790-7
Lee, Hyung-Yul; Zhao, Shuangping; Fields, P A et al. (2005) The extent to which relaxin promotes proliferation and inhibits apoptosis of cervical epithelial and stromal cells is greatest during late pregnancy in rats. Endocrinology 146:511-8
Zhao, Shuangping; Sherwood, O David (2004) Induction of labor with RU 486 (mifepristone) in relaxin-deficient rats: antepartum administration of relaxin facilitates delivery and increases pup survival. Am J Obstet Gynecol 190:229-38