Abstract

It has been shown that long-term high altitude hypoxia during pregnancy was associated with a decrease in cardiac contractility in fetal sheep. Given that hypoxia caused apoptotic cell death in fetal and neonatal rat cardiomyocytes, the present study tested the hypothesis that chronic hypoxia during pregnancy increases apoptosis in the fetal sheep heart. Pregnant (d 30) sheep were divided between normoxic control and chronically hypoxic (maintained at high altitude, 3,820 m, PaO2: 60 Torr for 110 days) groups. Hearts were isolated from near-term (d 140) fetal sheep, and samples from all four chambers, right and left atria, and right and left ventricles were obtained. Apoptotic cells from each sample were determined by examining nuclear chromatin morphology using fluorescent DNA-binding dye Hoechst 33258, and by measuring DNA fragmentation with an ELISA kit from Boehringer Mannheim. In normoxic control animals, the fetal heart contained an average of from 21.7±3.0 to 27.4±3.2 apoptotic cells/103cells, and there was no difference among the four chambers. Chronic hypoxia had a tendency to increase apoptosis from 21.7±3.0 to 27.8±2.9 apoptotic cells/103cells in the left ventricle, but it did not reach a significant level. The levels of apoptotic cells in the right ventricle and the atria were the same between the control and hypoxic hearts. Similar findings were obtained with the DNA fragmentation measurement. The results suggest that chronic hypoxia did not change apoptotic cell levels in the fetal heart, and exclude the role of apoptosis in the decreased function in the fetal sheep heart exposed to long-term high altitude hypoxia.

LLU Discipline

Anatomy

Department

Anatomy

School

Graduate School

First Advisor

Lubo Zhang

Second Advisor

Paul J. McMillan

Third Advisor

Kenneth R. Wright

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2001

Date (Title Page)

6-2001

Language

English

Library of Congress/MESH Subject Headings

Fetal Heart; Fetal Anoxia; Anoxia

Type

Thesis

Page Count

ix; 40

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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