Fatores que afetam a síntese de mediadores inflamatórios da resposta imune inata endometrial de bovinos

Abstract

Due to the high occurrence of uterine diseases in the postpartum period of dairy cows and directly impacting the reproductive indices of animals, this study also aimed to evaluate the gene expression of proinflammatory mediators in the endometrium of crossbred dairy cows with and without SE, at 14 and 35 days in milk (DIM). The physical and reproductive system evaluations of the animals were performed weekly at 7, 14, 28 and 35 DIM. At 14 and 35 DIM, endometrial samples were collected by uterine biopsy. The samples were analyzed by the qRT-PCR technique, to evaluate the gene expression of the pro-inflammatory cytokines IL1β, IL6, IL8 and CCL5. In addition, it was collected endometrial swabs using the endometrial brush technique (cytobrush) for endometrial cytology and diagnosis of SE. The IL1β gene expression to the group without SE was higher than the SE group at 14 DIM (p = 0.0009). There was a difference in the IL8 gene expression at 14 DIM between groups (p < 0.001) and in relation to the collection time, with greater expression at 14 DIM when compared to 35 DIM (p = 0.0011). There were no differences in the IL6 and CCL5 gene expression between cows with and without SE and the collection time. In conclusion, the crossbred dairy cows without uterine diseases have a more robust immune response at 14 DIM, with greater expression of the proinflammatory cytokines IL1β and IL8 when compared to the cows with SE, being the analysis of the gene expression of these cytokines a potential tool for the early diagnosis of SE. Besides that, in view of the kisspeptin is a neuropeptide known for its potent stimulatory action of the gonadotropin-releasing hormone (GNRH), responsible for centrally regulating ovarian function and the estrous cycle. In addition to its fundamental role in the regulation of the reproductive axis, kisspeptin is able to modulate the function of cells in the immune system, with possible regulation in the interaction of these two systems. The present study also aimed to evaluate the modulatory role of kisspeptin in the innate endometrial immune response of bovine females. Therefore, five experiments were carried out and a total of 24 reproductive tracts of nulliparous bovine females were used, collected in a commercial slaughterhouse, for processing through the ex vivo endometrium cultivation technique. The treatments used in the cultivation of endometrial explants from caruncular and intercaruncular regions consisted of kisspeptin (Kp 10-5 M; Kp 10-6 M; Kp 10-7 M), antagonist p234 (p234 10-5 M; p234 10-7 M; p234 10-9 M), progesterone (5ng/mL) and dexamethasone (5ng/mL), challenged or not with 1μg/mL lipopolysaccharide (LPS), at 12 and 24 hours of culture. Gene expression of cytokines IL6, IL1β and concentration of cytokines IL6, IL1β and IL8 were evaluated by qRT-PCR and ELISA, respectively. There was no difference in the gene expression of IL1β and IL6 cytokines and in the production of IL6, IL1β and IL8 in any of the treatments performed with different concentrations of kisspeptin. It was concluded that kisspeptin had no modulatory effect on the innate immune response of the bovine endometrium when the ex vivo endometrial culture model was used.