Superestimulação ovariana e o perfil de mucinas no oviduto bovino

Abstract

The oviduct is the site where sperm capacitation, fertilization and early embryonic development take place. During the estrous cycle, changes in the oviduct are mainly modulated by the hormones estradiol (E2) and progesterone (P4). While E2 stimulates proliferation and hypertrophy of secretory cells, P4 has the opposite effect, causing atrophy and reduction of cell secretion. In addition, these hormones are related to changes in the oviductal fluid throughout the reproductive cycle of bovine females. Ovarian superstimulation (SEOv) enables increased reproductive rates in bovine females, greater selection intensity, reduced generation interval, greater availability of animals for replacement and, in addition, also allows a female with a high zootechnical standard to be used in a variety of ways. a more rational way, providing a large number of descendants in a short time. In this context, there is evidence that ovarian superstimulation (vSEO) increases E2 levels in oviductal tissue in cattle. E2 levels in bovine oviductal tissue and the mucins present play important roles in the reproductive physiology of these animals. Within this context, the aim of this study was to investigate the impact of SEOv with FSH or FSH/eCG in regulating the production of mucins present in the oviduct. Therefore, Nelore cows (Bos taurus indicus) were submitted to SEOV using FSH (n=5), FSH/eCG (n=5) or synchronized (control group, n=5). Cows at a random stage of the estrous cycle received a progesterone-releasing vaginal insert (1.0 g) and estradiol benzoate (2.5 mg, i.m.) on day 0. Cows underwent vSEO using the FSH and FSH protocol /eCG received FSH administration twice daily from days 5 to 8. In the FSH/eCG protocol, the last two doses of FSH (Day 8) were replaced by two doses of eCG (total dose = 400 IU, i.m.). On day 7, all cows received 150 mg of d-cloprostenol i.m. twice/day. On day 8, the progesterone-releasing vaginal inserts were removed and the cows were slaughtered. After slaughter, the oviducts (ampulla and isthmus) were collected, fixed and subjected to histological processing for Alcian blue staining and quantification of mucin 9 mRNA abundance (MUC9). Ampullary and isthmus segments were analyzed separately and the effect of SEOv was investigated by parametric ANOVA and means were compared by Tukey-Kramer test. Data are presented as means ± S.E.M. Differences were considered significant when P<0.05. In summary, superstimulatory FSH treatment combined with eCG increased the abundance of total mucins in the isthmus (p<0.05) and ampulla (p<0.05). Additionally, SEOv, regardless of treatment, increased the relative abundance of the gene that encodes mucin 9, only in the ampoule (p<0.05). In conclusion, SEOv using FSH combined with eCG determines an increase in the expression and secretion of mucins in the bovine oviduct.