Fitzpatrick R J
Ann Rech Vet. 1977;8(4):438-49.
In sheep and goats changes in the wall of the uterine cervix associated with parturition were studied in relation to the preparturient sequence of endocrine events. Evidence was obtained of separation of collagen fibrils, possibly due to changes in the electrostatic binding of the fibrils by glycosaminoglycans. The mechanical properties of the cervix were investigated quantitatively on isolated tissues by radial loading to destruction, and by progressive extension on a tensometer; the extension experiments revealed that at parturition (but not before) the cervical wall acts mechanically as if composed of two different tissues, one of which, the collagen layer, changes profoundly at parturition to facilitate dilatation. Resistance to dilatation (compliance) was investigated in vivo using indwelling intracervical balloons which could be inflated with water at standard speed. This permitted serial observations in the same animal during the progress of parturition induced with foetal dexamethasone (sheep) or maternal cloprostenol (goats). Compliance increased progressively in all 13 parturient animals, but not in untreated controls, and this increase occurred coincidentally with the expected fall in progesterone and rise in oestrogen concentrations: it occurred before the preparturient rise in PGF. Meclofenamic acid administration to cloprostenol treated goats successfully delayed the PGF surge and delayed parturition but did not delay the increase in compliance which reached maximum within the 36 hours of treatment with the PG synthetase inhibitor.
研究了绵羊和山羊子宫颈壁在分娩时的变化与产前内分泌事件序列之间的关系。获得了胶原纤维分离的证据，这可能是由于糖胺聚糖对纤维静电结合的改变所致。通过对分离组织进行径向加载直至破坏以及在张力计上进行渐进伸展，对子宫颈的力学性能进行了定量研究；伸展实验表明，在分娩时（而非分娩前），子宫颈壁在力学上的表现就好像是由两种不同的组织组成，其中一种，即胶原层，在分娩时会发生深刻变化以利于扩张。使用可通过标准速度注水的宫颈内留置球囊在体内研究了对扩张的阻力（顺应性）。这使得在使用胎儿地塞米松（绵羊）或母体氯前列醇（山羊）诱导分娩的过程中，能够对同一动物进行连续观察。所有13只分娩动物的顺应性均逐渐增加，而未治疗的对照组则没有，这种增加与预期的孕酮下降和雌激素浓度上升同时发生：它发生在产前PGF上升之前。对用氯前列醇治疗的山羊给予甲氯芬那酸成功延迟了PGF激增并延迟了分娩，但并未延迟顺应性的增加，顺应性在用PG合成酶抑制剂治疗的36小时内达到最大值。
