Masters Theses

Date of Award

8-1981

Degree Type

Thesis

Degree Name

Master of Science

Major

Zoology

Major Professor

Roland M. Bagby

Committee Members

Mary Ann Handel, Alex Shivers, Dewey Bunting

Abstract

The purpose of this study was to isolate a single myometrial cell from the uterus of the guinea pig and to make a quantitative study of growth changes in the pregnant myometrium by measuring the change of myometrial smooth muscle cells per unit area (SMC/A), to measure changes in smooth muscle cell width (SMCW), and to observe the change in percent smooth muscle cell area (%SMCA = (Area occupied by SMC/total area of micrograph) x 100) in various segments of the uterus during the estrous cycle and throughout gestation.

Single myometrial cells were isolated from the uteri of the pregnant and nonpregnant guinea pig during various stages of the estrous cycle and with various gestation durations. After incubation of myometrial tissue pieces in various collagenase media for 3-5 hr. Aliquots of the supernatant were placed on a slide and observed periodically with a Nikon-Suke Phase Contrast microscope to check for the presence of isolated myometrial cells. Photomicrographs were made with a Nikon micrographic camera to collect data for the study of cell configurations and for the calculation of the change in area of cell profile of myometrial smooth muscle during the last half of gestation.

The results form the isolated single myometrial smooth muscle cell studies indicate that the most successful technique requires treatment of myometrial segment with 2 mM EGTA, pH 7.4 for 1 hr. with subsequent incubation in a crude collagenase medium for 3-5 hr. with an optimal yield of cells isolated at week 7 of gestation. A two fold increase in area of cell profile was observed in isolated smooth muscle cells during the last half of gestation.

The major finding of this research was that %SMCA and SMCW changes with the reproductive state of the uterus as well as with gestation duration. These responses were not uniform throughout the entire myometrium, but a differential response was observed among the various uterine sites. A 70% increase in SMC/A was observed in both upper and However, lower uterine horns during the first two weeks of gestation. no change in SMC/A is observed in the caruncle and intercaruncle sites at any stage of gestation.

A cross sectional study is limited in providing data about growth changes of myometrial smooth muscle cells since it does not provide accurate measurement of length. An accurate assessment of cell growth was not possible during this study since changes in SMCW might be related to factors other than growth changes.

The isolated single myometrial cell may provide a useful model for studying and testing the combined effects of hormones, stretch and other physiological and/or physical factors on the morphological changes of the myometrium.

Data obtained from the measurements of quantitative changes of smooth muscle cells in the various uterine sites in the pregnant and nonpregnant uterus provides a statistical basis for future investigations on the distribution of hormonal and neurotransmitter receptor sites in the myometrium during gestation. In future studies, there is a need for techniques which will permit more accurate measurements of quantitative growth changes in myometrial smooth muscle cells during gestation with known physiological changes in uterine activity at partuition.

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