Differential expression of transforming growth factor-beta I and transforming growth factor-beta receptors in myometrium of women with failed induction of labor, no labor, and preterm labor

OBJECTIVE: Comparative analysis of transforming growth factor-beta 1 (TGF-b eta 1) and TGF-beta receptor type I and type II messenger RNA (mRNA) and pr otein expression in myometrium of women who had unsuccessful labor inductio n, with those without labor or in preterm labor complicated by chorioamnion itis. METHODS: Small segments of myometrium were collected from women who were un dergoing cesarean delivery for unsuccessful labor induction (n = 5), electi ve cesarean without labor (n = 5), or cesarean delivery for complications r elated to preterm labor and chorioamnionitis (n = 5). Total RNA was isolate d from these tissues and subjected to competitive quantitative reverse-tran scription-polymerase chain reaction (Q-RT-PCR) to determine the level of TG F-beta 1, and TGF-beta type I and type II receptor mRNA expression. Tissue sections were prepared from paraffin-embedded specimens and immunostained f or TGF-beta 1 and receptor proteins using specific polycolonal antibodies. The data were analyzed bu unpaired Student t test and Kruskal-Wallis analys is of variance. RESULTS: Myometrium from women who had unsuccessful labor induction express ed higher levels of TGF-beta 1 mRNA (2.21 +/- 0.28 x 10(6) copies/mu g of t otal cellular RNA) than those with preterm labor (4.53 +/- 0.2 x 10(5) copi es), or without labor [3.13 +/- 2.6 x 10(4) copies (P < .05)]. The level of TGF-beta type I receptor mRNA expression did not very; however, type II re ceptor expression was significantly lower in myometrium from preterm labor (1.36 +/- 0.36 x 10(5) copies) compared with those from unsuccessful labor induction (3.42 +/- 0.42 x 10(6) copies) or without labor (9.65 +/- 3.2 x 1 0(5) copies). Immunoreactive TGF-beta 1 and TGF-beta receptor proteins were present in all myometrial tissues, and their intensity reflected that of t he mRNA expression in these tissues. CONCLUSION: TGF-beta 1 and TGF-beta type II receptors are expressed differe ntly in myometrium of women who had unsuccessful labor induction compared w ith those without labor or with preterm labor complicated by chorioamnionit is. Because TGF-beta is a key regulator of tissue remodeling which is centr al to initiation of normal labor, alterations in TGF-beta and/or TGF-beta r eceptor expression may lead to changes in the outcome of labor, at least at the myometrial level. Copyright (C) 1999 by the Society for Gynecologic In vestigation.