McDougall J J, Giles R W, Bray R C, Hart D A
Joint Injury and Arthritis Research Group, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Am J Physiol. 1998 Oct;275(4):R1380-5. doi: 10.1152/ajpregu.1998.275.4.R1380.
The ligaments of weight-bearing joints are known to become mechanically inferior during pregnancy, and it has been postulated that this may be due to changes in tissue perfusion. Calcitonin gene-related peptide (CGRP) and epinephrine exert a tonic influence on the vasculature of the medial collateral ligament (MCL), and the present study examined whether these vasoactive influences were altered by pregnancy. Ligament perfusion experiments were performed on primigravid New Zealand White rabbits with the use of laser Doppler perfusion imaging. In pregnant animals (day 29), MCL basal perfusion fell significantly compared with control; however, values returned to normal 5 days postpartum. In normal joints, topical application of CGRP resulted in a dose-dependent increase in MCL perfusion, whereas epinephrine administration caused a dose-dependent fall in blood flow. During pregnancy, the vasodilator effect of CGRP was completely abolished, whereas adrenergic vasoconstriction was greater than normal. Both responses returned postpartum. Pregnancy in the rabbit produces hypoemia in the MCL, and this phenomenon may be effected by a tempering of CGRP dilator responses and an augmentation of alpha-adrenoceptor-mediated vasoconstriction.
众所周知，负重关节的韧带在怀孕期间会在机械性能上变差，据推测这可能是由于组织灌注的变化所致。降钙素基因相关肽（CGRP）和肾上腺素对内侧副韧带（MCL）的血管系统有持续性影响，本研究探讨了这些血管活性影响是否会因怀孕而改变。利用激光多普勒灌注成像技术，对初产新西兰白兔进行韧带灌注实验。在怀孕动物（第29天）中，与对照组相比，MCL基础灌注显著下降；然而，产后5天数值恢复正常。在正常关节中，局部应用CGRP会导致MCL灌注呈剂量依赖性增加，而给予肾上腺素则会导致血流呈剂量依赖性下降。在怀孕期间，CGRP的血管舒张作用完全消失，而肾上腺素能血管收缩作用则比正常情况更强。两种反应在产后均恢复。兔子怀孕会导致MCL出现贫血，这种现象可能是由于CGRP舒张反应减弱和α-肾上腺素能受体介导的血管收缩增强所致。
