Investigations on the potential role of prostaglandin E2 in canine uterine inertia

Involvement of Oxytocin and Progesterone Receptor Expression in the Etiology of Canine Uterine Inertia

“…Despite the frequent occurrence of PUI in dogs and its severe consequences for maternal and offspring survival, the exact etiology is still unknown. Up to now, only few studies have investigated its pathophysiology from a molecular biology approach looking directly at the level of the uterus [ 16 , 17 , 32 , 45 , 46 ]. As both oxytocin and progesterone are crucial hormones during parturition, we hypothesized and identified altered expression of the respective receptors as potential causes for PUI.…”

“…The significantly higher OXTR mRNA expression (ratio) in IP samples obtained from PUI (and PUI-N) dams compared to OD might be a consequence of the absence of intracervical pressure due to the fact that no puppy had been born and, thus, having insufficient systemic OXT release, as previously postulated by Tamminen et al [ 32 ]. It is worth noting that comparison of the OD and PUI samples was shown to be suitable in previous studies to gain further insight into the pathophysiology of canine dystocia and specifically PUI [ 15 , 16 , 17 , 32 , 45 , 46 ].…”

“…The samples utilized in this study were already used previously by our research group [ 45 , 46 ] and our collaborators [ 15 , 16 , 17 ].…”

“…As the litter size was quite variable, the PUI group was subdivided into small/normal/large litter size (PUI-S, PUI-N, PUI-L) in relation to the average litter size of the respective breed [ 74 ]. Litter size within the breed average ± 1 standard deviation (SD) was considered as normal (PUI-N), whereas less or more than ± 1 SD was assigned to PUI-S or PUI-L, respectively [ 15 , 16 , 17 , 45 , 46 ].…”

“…Collected tissue was divided into different parts for subsequent mRNA and protein analysis, as well as for histology and immunohistochemistry (IHC) as previously described [ 45 , 46 ]. For mRNA analysis, samples were covered with RNAlater ® (Ambion Biotechnologie GmbH, Wiesbaden, Germany) immediately post-surgery, temporarily stored at 4 °C, before being kept at −80 °C until extraction.…”