Uterine pathologies and ex vivo blood-perfused model
Uterine pathologies are the most common causes of infertility in mares.
This study aimed to establish an ex vivo blood-perfused model for equine uteri and investigate the possible effects of different cycle stages and defeat much of the uterine pathologies.
Uteri (n = 13) were collected at an abattoir, flushed with preservation solution, transported to the laboratory on ice, and isolated perfused with autologous blood for 6 h (n = 12).
For negative control, one uterus was handled as described but left without perfusion for 6 h.
The cycle stage was determined by examination of the ovaries for the presence of Graafian follicles or corpora lutea and analysis of plasma progesterone concentration.
Sonomicrometry crystals were implanted into the myometrium to record spontaneous contractions and the response to 0.5 IU oxytocin after 6 h of perfusion.
Analyses of the arterial and venous perfusate were performed every hour to determine glucose consumption, lactate production, pH, lactate dehydrogenase activity (LDH), and potassium concentration (K+).
The uteri's glucose consumption and lactate production increased over time, but no differences among cycle stages were detected.
No changes for LDH were observed. K+ increased after 4 h of perfusion (p < 0.05), but was unaffected by the cycle stage.
Spontaneous contractions were present in all perfused uteri, but myometrial activity in the negative control was limited to the 2nd hour of perfusion.
No effects of cycle stage on contraction amplitude and duration after oxytocin administration were detected.
The cycle stage did not affect frequency, amplitude, duration of contractions, or edema formation.
Histology revealed congestion of endometrial capillaries after 4, 5, and 6 h perfusion time. In conclusion, the ex vivo model was capable of supporting the functionality of equine uteri for 6 h.
However, viability and histomorphology of the endometrium appeared to be impaired after 4 h of perfusion.