RESUMO
The cytokine context present in the reproductive tract of cows is closely involved in normal uterine functions, including the estrous cycle and the establishment and maintenance of pregnancy. However, the roles of some cytokines in the uterus, and their relation with reproductive performance remain to be elucidated. Thus, this study aimed to examine the protein expression of several cytokines such as TNFα, IL-6, IL-8, IFNγ, IL-4, and TGF-ß3 in endometrial biopsies previous to conception, to evaluate the possible association with delayed conception in dairy cows. Protein expression levels were evaluated by immunohistochemistry. Results showed that the protein expression levels of TNFα, IL-6, IL-4 and TGF-ß3 were not associated with the parturition-conception interval, whereas the high protein expression levels of IFNγ were associated with the parturition-conception interval. Finally, the low protein expression of IL-8 showed a statistical tendency to be associated with delayed conception. This is the first report about the protein expression of IFN-γ in the endometrium of dairy cows and also, this cytokine could enhance the favorable conditions to achieve an early pregnancy.
RESUMO
The cytokines of the interleukin-1 (IL-1) family are closely involved in the resolution of inflammation in cows with metritis and endometritis. However, little is known about the role of these cytokines beyond uterine regression in the absence of disease, especially around conception. Thus, the aim of this study was to examine the gene and protein expression of IL-1α, IL-1ß, IL-1RI, IL-1RII and IL-1Ra in endometrial biopsies previous to conception, to evaluate the possible association of these cytokines with delayed conception in dairy cows. Gene and protein expression levels were evaluated by real-time PCR and immunohistochemistry, respectively. The gene expression levels of cytokines were not associated with the duration of the period to conception following parturition. However, high protein expression of IL-1ß and low protein expression of IL-1Ra were significantly associated with early conception. These results suggest that an imbalanced protein expression of IL-1ß and IL-1Ra in the endometrium of dairy cows could be part of the maternal immune response mechanism necessary to propitiate early conception and probably to maintain pregnancy.
Assuntos
Doenças dos Bovinos , Endometrite , Feminino , Gravidez , Bovinos , Animais , Proteína Antagonista do Receptor de Interleucina 1/genética , Endométrio , Fertilização , Endometrite/genética , Endometrite/veterinária , Biópsia/veterinária , Doenças dos Bovinos/genéticaRESUMO
The nutritional conditions and immune status of dairy cows affect reproductive performance. This study was conducted with the aim to analyze the phagocytic activity (PA) and phagocytic capacity (PC) of circulating monocytes after the period of transition from pregnancy to lactation, to evaluate possible associations with duration of time period to conception following parturition. Results indicated PA was not associated with duration of time period to conception following parturition. In contrast, cows with a lesser PC conceived earlier (98 ± 9 days in milk, DIM) than those with a greater PC (168 ± 15 DIM). Based on these results, to analyze the association of the hormonal and metabolic milieu with the PA and PC, the animals were grouped considering the days to conception following parturition. In the group with the greater number of days to conception (>168 DIM), the PA was associated with concentrations of progesterone and beta-hydroxybutyrate (BHB) at 90 DIM and glucose at 120 DIM, whereas PC was associated with the concentrations of progesterone, cortisol and glucose at 90 DIM, non-esterified fatty acids (NEFA) at 120 DIM, 17ß-estradiol at 150 DIM, and 17ß-estradiol and BHB at 180 DIM. Overall, these results represent a new perspective related to the reproductive performance of dairy cows. The modifications of cellular functions may be useful for predicting the onset of health complications in dairy cows and to manage cows in ways that result in an enhanced fertility during the subsequent lactational period.
Assuntos
Bovinos/fisiologia , Fertilização/fisiologia , Monócitos/fisiologia , Fagocitose/fisiologia , Animais , Feminino , Lactação/fisiologia , Parto , GravidezRESUMO
The most important regulators of tissue remodelling during ovarian follicular growth, development, ovulation and atresia are gonadotropins, steroid hormones, growth factors and different proteolytic enzymes. Matrix metalloproteinases (MMPs) such as collagenase or gelatinase (i.e. MMP-1, -8, -2 and -9) and associated tissue inhibitors of metalloproteinases (TIMP-1, -2, -3 and -4) control connective tissue remodelling during follicular rupture. In this study, we hypothesized that an imbalance in the MMP-TIMP system may be an intra-ovarian component that contributes to the pathogenesis of cystic ovarian disease (COD) in cows. Taking into account that the control of MMP activity by TIMPs could determine their effects in both physiological and pathological conditions, MMP and TIMP mRNA and protein expression was examined by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), respectively, in ovaries from control cows and cows with COD. Expression of mRNA encoding MMP-2, TIMP-1 and TIMP-2 was lower in follicular cysts than in control pre-ovulatory follicles, while the results by IHC showed this imbalance only for TIMP-2 protein expression. Additional analysis by zymography to evaluate the gelatinase activity of MMP-2 and MMP-9 demonstrated higher MMP-2 activity in follicular fluid (FF) of cysts than in FF of pre-ovulatory follicles. On the other hand, MMP-9 activity was increased in follicular cysts and absent in the FF of pre-ovulatory follicles. These findings suggest that the altered mRNA expression and activities of the MMP-TIMP system may be related to the failure in ovulation and follicular development observed in COD.