LAUSR

Background: Uterine torsion, the most complicated cause of maternal dystocia recorded in bovine, usually followed by incomplete cervical dilatation after successful detorsion, which interfere with vaginal fetal delivery. Aim: This study aimed to evaluate the histopathological changes, variable collagen concentrations, and vascular endothelial growth factor expressions in uterine and cervical tissues following successful detorsion. Methods: Animals were classified into four groups; normally calved cases (group A), cases that respond successfully to detorsion and followed by vaginal fetal delivery without (group B) or with (group C) cervical laceration, and cases that suffered from failure of complete cervical dilatation after successful detorsion (group D). Results: Histopathological findings revealed variable changes in all uterine torsion affected groups, which were characteristic and marked in animals that suffered from failure of complete cervical dilatation following successful detorsion. Moreover, failure of cervical dilatation was associated with the highest collagen concentrations as shown by Masson trichrome stain. On the other hand, immunohistochemical findings showed that the normally calved cases have the highest vascular endothelial growth factor expression compared with animals that suffered from failure of complete cervical dilatation. Conclusion: Our results showed that the vascular endothelial growth factor is essential for cervical dilatation and its lower expression is accompanied by incomplete cervical dilatation following successful detorsion.