Evaluation of JAK/STAT Signaling Pathway-associated Protein Expression at Implantation Period: An Immunohistochemical Study in Rats

Objective: The implantation period of gestation is a complex process in which numerous molecular pathways play a role. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway is one of the evolutionarily conserved cascades used to transduce a multitude signals for several biological events such as implantation and uterine receptivity. Previous studies have indicated that the implantation process is disrupted by the lack of proteins involved in this pathway. However, our literature knowledge showed that there is no study evaluated the expression of JAK/STAT signaling pathway-associated proteins during the implantation period. This study investigated the expression patterns of JAK/STAT signaling pathway-associated proteins in rats by immunohistochemical (IHC) staining according to gestational days.
Methods: In this study, thirty Wistar Albino rats weighing 250-300 g, without any problems in their menstrual cycles, were used. The pregnant animals were sacrificed on the 4th, 5th, and 6th days and histochemical and IHC analysis were performed on the uterine tissues taken from these animals.
Results: In this study, protein expression of JAK1, JAK2, JAK3, STAT2, STAT3, STAT4, STAT5, and STAT6 belonging to the JAK/STAT pathway was evaluated in the uterine surface epithelium, gland structures, antimesometrial region, cells of the immune system, myometrium, mesometrial region and decidual cells, which are associated with the implantation process. The result of this evaluation reveals that the expression levels of these proteins in the JAK/STAT pathway vary in different days of the implantation period in implantation-related structures.
Conclusion: This study indicates that JAK/STAT signaling pathway-associated proteins can function actively in the regulation of the immunological response of the uterus and embryo-uterus interaction during the implantation period in rats. However, the findings obtained from advanced research on JAK/STAT pathway can be used for treating recurrent pregnancy failures and in enhancing assisted reproductive technology.