Avaliação da resposta imune inata uterina de vacas gir ovariectomizadas sob influência da progesterona

Abstract

Studies on uterine immunity may help in the understanding of uterine infections, since the establishment, severity, and persistence of different types of infection are related to innate and acquired immunity, uterine environment condition, and genetic factors. The hypothesis of the present study was that progesterone in vivo reduces the uterine innate immune response from Gir cows. The objective of this study was to verify if ovariectomized cows exposed to progesterone had a reduced uterine innate immune response after 14 days of exposure to it. Eight cows of the Gir breed with mean age of 30 months, primiparous and average weight of 408.7 kg, were randomly divided into two groups, with four animals each and submitted to ovariectomy surgery. After the rest period and post-surgical recovery, in the D-14 was performed the general physical examination and the specific to the female genital tract; blood samples were collected for hemogram, leukogram and proteinogram; samples were collected for cytology and gene expression, and intravaginal progesterone devices were introduced in both treatment and control groups. In D-7, after the general physical examination, the devices of P4 placed at the previous moment (D-14) were replaced in all the animals, remaining for another seven days. At the time LPS (D0), the implants were removed, the procedures performed in D- 14 were repeated; LPS was administered to the animals of the LPS Group and NaCl 0.9% solution in the Control Group animals. On the day after the infusion (D+1), all evaluations were performed again. All animals were clinically healthy. Regarding vital parameters, body temperature was lower (P = 0.0004) at time D+1, but remained within the parameters consulted. In the leukogram, the LPS group had values of segmented and bands above the reference standards at the D+1, evidencing neutrophilia with left shift, being that the LPS Group presented values higher than the Control Group at D+1 (P = 0.028) and had a reduction in the amount of monocytes (P = 0.006). In endometrial cytology, there was an increase in the number of polymorphonuclear cells in both groups at time D+1 (P = 0.0006). During the assessment of the genital system, the right uterine horn diameter increased in the LPS Group after LPS infusion (D+1), compared to the Control Group (P = 0.026). It was concluded that the endometrium of Gir cows, when exposed to LPS, being under the influence of progesterone undergoes changes, generating an immune response, which causes local and systemic response. This fact demonstrates that the methodology and concentration of LPS used may be a model for later studies regarding the uterine innate immunity of cattle.