Maturation of ovine uterine smooth muscle during development and the effects of parity

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Abstract

Objectives: To characterize changes in myometrial contractile proteins and myosin heavy chain (MHC) isoforms during ovine fetal and neonatal development and after pregnancy. We hypothesized that ovine myometrium demonstrates progressive cellular differentiation and maturation which begins in utero and extends into the postnatal period, and that pregnancy causes further cellular alterations. Methods: Myometrium was obtained from female fetal (72- to 140-days of gestation, n = 19; term = ~145 days), postnatal (1 day to 3 months, n = 25), and parous noncycling nonpregnant (n = 9) sheep to measure total and soluble proteins, actin, MHC, and MHC isoforms. Contractile proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and expression of 200-kD MHC isoforms were determined with Western immunoblots. Results: The contents of total and soluble proteins and actin and total myosin gradually increase (P < .003) during ovine development. Although the contribution of smooth-muscle 204-kD MHC increased (P < .001) from 23 ± 8% of total MHC at <100 days of gestation to 75 ± 2% 3 to 4 months postnatally, the 200-kD species fell proportionately. Before birth, MHC-B, a fetal isoform, is the predominant 200-kD protein; postnatally, it is replaced by SM2, demonstrating a switch from a synthetic to a mature contractile smooth-muscle phenotype. Pregnancy is associated with further increases in actin contents and redistribution of the contents of the 204-kD and SM2 MHC isoforms. Conclusions: Although the fetal and postnatal uterus has no known functional demand, ovine myometrial differentiation and maturation begin in the midtrimester and continue throughout the postnatal period. Thus, changes in smooth-muscle phenotype occur prenatally, as evidenced by a switch from MHC-B to SM2, which may signal completion of organ development and preparation for adult function. Pregnancy results in further modifications in myometrial proteins. Copyright (C) 2000 by the Society for Gynecologic Investigation.

Original languageEnglish (US)
Pages (from-to)284-290
Number of pages7
JournalJournal of the Society for Gynecologic Investigation
Volume7
Issue number5
DOIs
StatePublished - Sep 2000

Fingerprint

Myosin Heavy Chains
Muscle Development
Myometrium
Parity
Smooth Muscle
Sheep
Protein Isoforms
Pregnancy
Actins
Contractile Proteins
Proteins
Phenotype
Second Pregnancy Trimester
Myosins
Fetal Development
Sodium Dodecyl Sulfate
Uterus
Polyacrylamide Gel Electrophoresis
Western Blotting
Parturition

Keywords

  • Development
  • Fetus
  • Myometrium
  • Myosin
  • Pregnancy
  • Smooth muscle

ASJC Scopus subject areas

  • Obstetrics and Gynecology

Cite this

@article{d6e0bc2cff6c49cc8a9fd16e9231d478,
title = "Maturation of ovine uterine smooth muscle during development and the effects of parity",
abstract = "Objectives: To characterize changes in myometrial contractile proteins and myosin heavy chain (MHC) isoforms during ovine fetal and neonatal development and after pregnancy. We hypothesized that ovine myometrium demonstrates progressive cellular differentiation and maturation which begins in utero and extends into the postnatal period, and that pregnancy causes further cellular alterations. Methods: Myometrium was obtained from female fetal (72- to 140-days of gestation, n = 19; term = ~145 days), postnatal (1 day to 3 months, n = 25), and parous noncycling nonpregnant (n = 9) sheep to measure total and soluble proteins, actin, MHC, and MHC isoforms. Contractile proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and expression of 200-kD MHC isoforms were determined with Western immunoblots. Results: The contents of total and soluble proteins and actin and total myosin gradually increase (P < .003) during ovine development. Although the contribution of smooth-muscle 204-kD MHC increased (P < .001) from 23 ± 8{\%} of total MHC at <100 days of gestation to 75 ± 2{\%} 3 to 4 months postnatally, the 200-kD species fell proportionately. Before birth, MHC-B, a fetal isoform, is the predominant 200-kD protein; postnatally, it is replaced by SM2, demonstrating a switch from a synthetic to a mature contractile smooth-muscle phenotype. Pregnancy is associated with further increases in actin contents and redistribution of the contents of the 204-kD and SM2 MHC isoforms. Conclusions: Although the fetal and postnatal uterus has no known functional demand, ovine myometrial differentiation and maturation begin in the midtrimester and continue throughout the postnatal period. Thus, changes in smooth-muscle phenotype occur prenatally, as evidenced by a switch from MHC-B to SM2, which may signal completion of organ development and preparation for adult function. Pregnancy results in further modifications in myometrial proteins. Copyright (C) 2000 by the Society for Gynecologic Investigation.",
keywords = "Development, Fetus, Myometrium, Myosin, Pregnancy, Smooth muscle",
author = "Yvonne Arens and Kamm, {Kristine E.} and Rosenfeld, {Charles R.}",
year = "2000",
month = "9",
doi = "10.1016/S1071-5576(00)00074-5",
language = "English (US)",
volume = "7",
pages = "284--290",
journal = "Reproductive Sciences",
issn = "1933-7191",
publisher = "SAGE Publications Inc.",
number = "5",

}

TY - JOUR

T1 - Maturation of ovine uterine smooth muscle during development and the effects of parity

AU - Arens, Yvonne

AU - Kamm, Kristine E.

AU - Rosenfeld, Charles R.

PY - 2000/9

Y1 - 2000/9

N2 - Objectives: To characterize changes in myometrial contractile proteins and myosin heavy chain (MHC) isoforms during ovine fetal and neonatal development and after pregnancy. We hypothesized that ovine myometrium demonstrates progressive cellular differentiation and maturation which begins in utero and extends into the postnatal period, and that pregnancy causes further cellular alterations. Methods: Myometrium was obtained from female fetal (72- to 140-days of gestation, n = 19; term = ~145 days), postnatal (1 day to 3 months, n = 25), and parous noncycling nonpregnant (n = 9) sheep to measure total and soluble proteins, actin, MHC, and MHC isoforms. Contractile proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and expression of 200-kD MHC isoforms were determined with Western immunoblots. Results: The contents of total and soluble proteins and actin and total myosin gradually increase (P < .003) during ovine development. Although the contribution of smooth-muscle 204-kD MHC increased (P < .001) from 23 ± 8% of total MHC at <100 days of gestation to 75 ± 2% 3 to 4 months postnatally, the 200-kD species fell proportionately. Before birth, MHC-B, a fetal isoform, is the predominant 200-kD protein; postnatally, it is replaced by SM2, demonstrating a switch from a synthetic to a mature contractile smooth-muscle phenotype. Pregnancy is associated with further increases in actin contents and redistribution of the contents of the 204-kD and SM2 MHC isoforms. Conclusions: Although the fetal and postnatal uterus has no known functional demand, ovine myometrial differentiation and maturation begin in the midtrimester and continue throughout the postnatal period. Thus, changes in smooth-muscle phenotype occur prenatally, as evidenced by a switch from MHC-B to SM2, which may signal completion of organ development and preparation for adult function. Pregnancy results in further modifications in myometrial proteins. Copyright (C) 2000 by the Society for Gynecologic Investigation.

AB - Objectives: To characterize changes in myometrial contractile proteins and myosin heavy chain (MHC) isoforms during ovine fetal and neonatal development and after pregnancy. We hypothesized that ovine myometrium demonstrates progressive cellular differentiation and maturation which begins in utero and extends into the postnatal period, and that pregnancy causes further cellular alterations. Methods: Myometrium was obtained from female fetal (72- to 140-days of gestation, n = 19; term = ~145 days), postnatal (1 day to 3 months, n = 25), and parous noncycling nonpregnant (n = 9) sheep to measure total and soluble proteins, actin, MHC, and MHC isoforms. Contractile proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and expression of 200-kD MHC isoforms were determined with Western immunoblots. Results: The contents of total and soluble proteins and actin and total myosin gradually increase (P < .003) during ovine development. Although the contribution of smooth-muscle 204-kD MHC increased (P < .001) from 23 ± 8% of total MHC at <100 days of gestation to 75 ± 2% 3 to 4 months postnatally, the 200-kD species fell proportionately. Before birth, MHC-B, a fetal isoform, is the predominant 200-kD protein; postnatally, it is replaced by SM2, demonstrating a switch from a synthetic to a mature contractile smooth-muscle phenotype. Pregnancy is associated with further increases in actin contents and redistribution of the contents of the 204-kD and SM2 MHC isoforms. Conclusions: Although the fetal and postnatal uterus has no known functional demand, ovine myometrial differentiation and maturation begin in the midtrimester and continue throughout the postnatal period. Thus, changes in smooth-muscle phenotype occur prenatally, as evidenced by a switch from MHC-B to SM2, which may signal completion of organ development and preparation for adult function. Pregnancy results in further modifications in myometrial proteins. Copyright (C) 2000 by the Society for Gynecologic Investigation.

KW - Development

KW - Fetus

KW - Myometrium

KW - Myosin

KW - Pregnancy

KW - Smooth muscle

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