Collagen, glycosaminoglycans and matrix metalloproteinase-2 and metalloproteinase-9 in the cervix of the ewe during prepubertal development

Increasing cervical penetrability in sheep by long-acting treatments with oxytocin (Carbetocin) and/or prostaglandin E2 (Dinoprostone)

The aim was to study the effect of long-acting treatments with oxytocin (Carbetocin, Cb) and/or prostaglandin E2 (Dinoprostone, Dp) on cervical penetrability and collagenolysis in synchronized ewes (12 days MAP-eCG). At 42 h post eCG, ewes were treated with Cb (Group Cb, n = 6, 40 μg, i.m., Decomotón, Laboratorios Callier, Uruguay); Dp (Group Dp, n = 10, 10 mg, slow-release intravaginal device, Propess®, Ferring Pharmaceuticals Ltd., West Drayton, UK); combined Cb and Dp treatment (Group Cb+Dp, n = 8) and saline solution i.m. and a placebo intravaginal device (Group C, n = 10). Cervical penetrability increased from 0 h to 42 h post eCG (P < 0.003) in all groups, then decrease in Group C (P < 0.03) from 42 to 68 h post eCG, whereas remained unchanged in Groups Cb and Cb+Dp or increase at 54 h post eCG in Group Dp (P < 0.05). Thus, there was higher cervical penetrability in treated groups than Group C at the expected time of artificial insemination (54 h post eCG). At 54 h post eCG, collagen concentration was lower in Group Cb than in the others groups (P < 0.05), whereas the ratio between the activity of the activated and latent forms of MMP-2 was greater in Groups Cb and Cb+Dp than in Group C (P < 0.05). The increasing cervical penetrability induced by Cb, but not by Dp, could be explained by an increase in MMP-2-dependent collagen degradation. Furthermore, combined treatment with Cb and Dp did not enhance the effects induced by each hormone administered separately.

In vitro study of carbetocin, an oxytocin receptor agonist, and 4-phenylfuroxan-3-carbonitrile, a NO-releasing agent, as cervical dilatators in sheep

The aim was to study the effect of 4-phenylfuroxan-3-carbonitrile (Fx), a NO-releasing agent, and carbetocin, an oxytocin receptor agonist, on matrix metalloproteinases-2 (MMP-2) activity and PGE2 production in cervix from cycling sheep. Cervical explants were incubated during 12 h with MEM supplemented with increasing concentrations of Fx in DMSO (2 %) (0 to 300 μg/mL) with Cb (100 ng/mL) (Experiment 1, n = 15) and DMSO (2 %), DMSO + Cb (100 ng/mL) or DMSO + Fx (30 μg/mL) (Experiment 2, n = 10), and their respective controls. In the supernatants, activated (A) and latent (L) MMP-2 activities were determined by a SDS-PAGE zymography, PGE2 concentration by immunoassay and NO production indirectly as nitrites by spectrophotometry. Data were analyzed by ANOVA. The Cb treatment increase the A MMP-2 activity in DMSO (Experiment 1 at follicular phase and Experiment 2) or alone (Experiment 2) and increase the L MMP-2 activity (Experiments 1 and 2) (P < 0.02). The DMSO treatment also increase the L MMP2 activity (Experiment 2) (P < 0.0001). Treatment with Fx + DMSO increased the concentration of accumulated nitrites in the supernatant (P < 0.0001) (Experiment 1), but did not affect or decrease the activity of A and L MMP-2 (P < 0.04) (Experiments 1 and 2). The PGE2 concentration trend to increase with Cb treatment (P = 0.0614) and decrease with Fx+DMSO treatment (P < 0.0001) (Experiment 2). In conclusion, Cb and/or DMSO treatment of cervical explants increase the MMP-2 activity through PGE2-independent mechanisms, but Fx in DMSO fail in this, suggesting that the pre-treatment with Cb and/or DMSO could be used to increase cervical dilation in ewes.

Increasing matrix metalloproteinase-2 activity by treatment of ovine cervical explants with a long-acting analogue of oxytocin (Carbetocin) at the expected time of artificial insemination

The aim was to study the effect of long-acting analogue of oxytocin (Carbetocin) on cervical collagenolysis of MAP-eCG synchronized ewes. At the expected time of artificial insemination, five ewes were slaughtered (n = 5) and their cervical explants (100-200 mg) were incubated during 12 h with MEM supplemented with 0, 8, 16, 32 and 64 ng/mL of Cb. Activities of activated and latent forms of matrix metalloproteinases-2 and - 9 (MMP-2 and MMP-9, respectively) in the supernatant were determined by a SDS-PAGE zymography and prostaglandin E2 concentration by immunoassay. Data were analyzed by ANOVA test. The MMP-9 activity was detected weakly and sporadically. The activity of activated MMP-2 was higher in 32 ng/mL Carbetocin treated samples than in untreated samples (P < 0.03). The activity of latent MMP-2 tended to be higher in 32 ng/mL than in 8 ng/mL Carbetocin treated samples (P = 0.083). The activated/latent ratio of MMP-2 tended to be higher in 64 ng/mL Cb treated samples than in untreated samples (P = 0.089). Prostagladin E2 concentration was not affected by Carbetocin dose. The data show that Carbetocin treatment of cervical explants induces an increase in MMP-2 activity by prostaglandin E2-independent mechanisms, suggesting Carbetocin as a potential inducer of cervical dilation in sheep.

Collagen at the maternal-fetal interface in human pregnancy

The survival and development of a semi-allogenic fetus during pregnancy require special immune tolerance microenvironment at the maternal fetal interface. During the establishment of a successful pregnancy, the endometrium undergoes a series of changes, and the extracellular matrix (ECM) breaks down and remodels. Collagen is one of the most abundant ECM. Emerging evidence has shown that collagen and its fragment are expressed at the maternal fetal interface. The regulation of expression of collagen is quite complex, and this process involves a multitude of factors. Collagen exerts a critical role during the successful pregnancy. In addition, the abnormal expressions of collagen and its fragments are associated with certain pathological states associated with pregnancy, including recurrent miscarriage, diabetes mellitus with pregnancy, preeclampsia and so on. In this review, the expression and potential roles of collagen under conditions of physiological and pathological pregnancy are systematically discussed.