Bovine salpingitis: Histopathology, bacteriology, cytology and transcriptomic approaches and its impact on the oocyte competence.

The present study was performed to examine the histopathology, cytology, bacteriology and expression pattern of a targeted set of genes of cytokines in the oviduct of cows with inflammation (Experiment 1). In addition, the effects of oviductal fluid from cows with salpingitis on the oocyte maturation and fertilization in vitro were examined (Experiment 2). The most frequent bacterial co-infection was Escherichia coli and Fusobacterium necrophorum, which was always associated with severe histopathologic salpingitis. Out of 15 cows with histologically healthy uterus, only one cow (6.7%) displayed the histologic signs of mild salpingitis, whereas from 50 cows with endometritis, 48 cows (96%) showed histologically different grades of salpingitis. The mRNA expression of IL1β, CD14, IL8 and CASP3 was significantly different among all groups of salpingitis (P < 0.05) with the highest level of mRNA expression in the sever grade of salpingitis. Results of experiment 2 showed a significant decline in the oocytes with peripheral free mitochondria and fertilization rate in the salpingitis group than the no- salpingitis group (P < 0.05). In conclusion, our results showed that histologically detected salpingitis is in most cases associated with histologic and cytologic endometritis. The pattern of the gene expression of chemokines and cytokines was altered in association with different grades of salpingitis. Further, we observed a decline in the peripherally located mitochondria and lower fertilization rate in oocytes following addition of oviductal fluid collected from the cows with sapingitis to the maturation media.