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Pregnancy-induced changes in rabbit medial collateral ligament vasoregulation
J J McDougall1, R W Giles, R C Bray
1Joint Injury and Arthritis Research Group, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
The American Journal of Physiology
|October 2, 1998
Summary
Pregnancy reduces blood flow in knee ligaments, impairing their function. This study found pregnancy alters responses to vasoactive substances, affecting medial collateral ligament (MCL) perfusion.
Area of Science:
- Biomedical Engineering
- Physiology
- Orthopedics
Background:
- Ligament mechanical integrity is crucial for joint stability.
- Pregnancy-induced hormonal and physiological changes may affect ligamentous tissues.
- Altered tissue perfusion is a potential mechanism for pregnancy-related joint laxity.
Purpose of the Study:
- To investigate the impact of pregnancy on medial collateral ligament (MCL) perfusion in rabbits.
- To determine if pregnancy alters the vasoactive responses of the MCL to calcitonin gene-related peptide (CGRP) and epinephrine.
- To elucidate the role of vascular changes in pregnancy-related ligament alterations.
Main Methods:
- Utilized laser Doppler perfusion imaging for quantitative assessment of MCL blood flow in vivo.
- Compared perfusion in pregnant (day 29) and non-pregnant control rabbits.
- Administered topical CGRP and epinephrine to assess dose-dependent vascular responses in the MCL.
Main Results:
- MCL basal perfusion was significantly reduced in pregnant rabbits compared to controls.
- Pregnancy abolished the vasodilatory effect of CGRP on MCL perfusion.
- Pregnancy augmented the vasoconstrictive response to epinephrine in the MCL.
Conclusions:
- Pregnancy induces hypoperfusion in the rabbit MCL.
- Altered CGRP-mediated vasodilation and enhanced alpha-adrenergic vasoconstriction contribute to pregnancy-related MCL hypoperfusion.
- These vascular changes may underlie the mechanical inferiority of ligaments during pregnancy.