BOR - Papers in Press, published online ahead of print
May 28, 2003.
Biol Reprod 2003, 10.1095/biolreprod.102.013474
BIOLOGY OF REPRODUCTION 69, 10531059 (2003)
DOI: 10.1095/biolreprod.102.013474
© 2003 by the Society for the Study of Reproduction, Inc.
Effects of Pulsatile Shear Stress on Nitric Oxide Production and Endothelial Cell Nitric Oxide Synthase Expression by Ovine Fetoplacental Artery Endothelial Cells1
Yun Li3,
Jing Zheng3,
Ian M. Bird3,4, and
Ronald R. Magness2,3,4,5
Perinatal Research Laboratories, Departments of Obstetrics and Gynecology,3
Pediatrics,4 and Animal Sciences
5 University of Wisconsin-Madison, Madison, Wisconsin 53715
Placental blood flow, endothelial nitric oxide (NO) production, and endothelial cell nitric oxide synthase (eNOS) expression increase during pregnancy. Shear stress, the frictional force exerted on endothelial cells by blood flow, stimulates vessel dilation, endothelial NO production, and eNOS expression. In order to study the effects of pulsatile flow/shear stress, we adapted Cellco CELLMAX artificial capillary modules to study ovine fetoplacental artery endothelial (OFPAE) cells for NO production and eNOS expression. OFPAE cells were grown in the artificial capillary modules at 3 dynes/cm2. Confluent cells were then exposed to 10, 15, or 25 dynes/cm2 for up to 24 h. NO production by OFPAE cells exposed to pulsatile shear stress was inhibited to nondetectable levels by the NOS inhibitor L-NMMA and reversed by excess NOS substrate L-arginine. NO production and expression of eNOS mRNA and protein by OFPAE cells were elevated by shear stress in a graded fashion (P < 0.05). The rise in NO production with 25 dynes/cm2 shear stress (8-fold) was greater (P < 0.05) than that observed for eNOS protein (3.6-fold) or eNOS mRNA (1.5-fold). The acute shear stress-induced rise in NO production by OFPAE cells was via eNOS activation, whereas the prolonged NO rise occurred by elevations in both eNOS expression and enzyme activation. Thus, elevations of placental blood flow and physiologic shear stress may be partly responsible for the increases in placental arterial endothelial eNOS expression and NO production during pregnancy.
1 Supported, in part, by National Institutes of Health Grants HL49210, HL57653, HD33255, HL64703, and HD38843. This study is in partial fulfillment of the Ph.D. degree in the Endocrinology-Reproductive Physiology Training Program (www.erp.wisc.edu).
2 Correspondence: Ronald R. Magness, Department of Obstetrics and Gynecology, University of Wisconsin, Perinatal Research Laboratories, 7E Meriter Hospital, 202 S. Park St., Madison, WI 53715. FAX: 608 257 1304; rmagness{at}facstaff.wisc.edu
Copyright © 2003 by the Society for the Study of Reproduction.