Expression of IL-23 in Gilt Endometrium and Oviduct After Insemination With Seminal Plasma, Spermatozoa or Semen Extender

Background: Signaling between seminal fluid and the female reproductive tract is required for a successful pregnancy to occur. Insemination with spermatozoa, seminal plasma and extender, is known to cause a rapid inflammatory response in the pig endometrium, which is characterized by an influx of neutrophils into the uterus. The temporary inflammatory response to semen involves induction of cytokines. In this study, potential functions for Interleukin-23 (IL-23) in the inflammatory response to different insemination treatments were examined by studying mRNA expression and immunostaining in samples of gilt oviduct (isthmus and infundibulum) and endometrium collected 35-40 h after insemination. Insemination was performed with either seminal plasma (SP, n = 4), spermatozoa in the extender Beltsville thawing solution (BTS) (SPZ, n = 4), or BTS alone (n = 4). In control gilts (n = 4) an insemination catheter was inserted without anything being inseminated. Any relation between expression of IL-23 and the presence of polymorphonuclear neutrophilic granulocytes (PMNs) in the endometrium was examined. Results: Results showed that IL-23 mRNA was expressed in the oviduct and in the endometrium. There was a significantly lower IL-23 mRNA expression in samples from gilts in the SPZ, SP and BTS treatment groups, compared with the controls. The control group also displayed significantly more neutrophils in samples collected 35-40 h after insemination compared with samples from the SP group. IL-23 immunolabelling was detected in a small number of separate cells as well as in the sub-epithelial connective tissue of the endometrium, the endosalpinx of the isthmus and infundibulum.Conclusions: All fluids used for insemination decreased the expression of IL-23 mRNA in the endometrium compared to catheter-insertion alone, indicating a possible role for IL-23 in the inflammatory response after insemination in gilts.