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.