Association between phagocytic activity of monocytes and days to conception after parturition in dairy cows when considering the hormonal and metabolic milieu

Endometrial distribution of bovine immune cells in relation to days to conception after parturition

In dairy cows, the processes involved in the resolution of uterine inflammation during the postpartum are closely related to improved fertility during the subsequent lactation period. Little is known, however, about the role and distribution of endometrial immune cell populations during the pre-implantation period. This study was aimed to analyze the endometrial distribution of several mononuclear immune cells (T cells, γδ T cells, B cells and macrophages) in healthy dairy cows during the postpartum, beyond the transition period, looking for its possible association with the parturition-conception interval (PCI) and delayed conception. The quantification of immune cells was evaluated by immunohistochemistry (IHC), and the expression of hormone receptors in immune cells was evaluated by double IHC. Dairy cows were grouped according to their PCI: PCI shorter than or equal to 90 DIM (PCI≤90), PCI between 90 and 120 DIM (PCI90-120), and PCI greater than 150 DIM (PCI≥150). The distribution of endometrial mononuclear immune cells was analyzed by a Generalized Linear Model, and the association of the distribution of mononuclear immune cells with delayed conception was evaluated with a Kaplan-Meier test. The cows from the PCI90-120 group showed the highest number of endometrial macrophages, and a lower number of B cells than the PCI≤90 group. Results also showed an association between the lower number of B cells in the endometrium during the pre-implantation period and earlier conception. Also, the present findings indicates that ESR and PR are expressed in the endometrial MØ, T cells, γδ T cells and B cells.

Effects of parity and early pregnancy on peripheral blood leukocytes in dairy cattle

Subfertility remains a major problem in the dairy industry. Only 35-40% of high-yielding dairy cows and 55-65% of nonlactating heifers become pregnant after their first service. The immune system plays a critical role in the establishment of pregnancy. However, it can also create challenges for embryo survival and contribute to reduced fertility. We conducted 2 separate experiments to characterize changes in subsets of peripheral blood leukocytes (PBL) and their phenotype over the estrous cycle and early pregnancy in heifers and cows. We used flow cytometry and RT-qPCR to assess protein and mRNA expression of molecules important for immune function. We observed that CD14+ monocytes and CD3+ T cells tended to be affected by pregnancy status in heifers, whereas CD8B+ lymphocytes and NCR1+ natural killer (NK) cells were affected during early pregnancy in cows. Changes in expression of immune function proteins appeared to be greater in heifers than cows. To compare the most striking differences between heifers and cows observed in the initial experiments, we conducted a third experiment where PBL sampled from heifers and cows were simultaneously collected and analyzed under the same experimental conditions. Our results indicate that, compared with heifers, cows had greater mRNA expression of proinflammatory cytokines (IFNG and IL6) and AHR protein along with greater percentage of MM20A+ neutrophils and myeloid cells expressing SIRPA, ITGAM and ITGAX. Moreover, animals that failed to become pregnant showed altered expression of anti-inflammatory molecules compared with cyclic and pregnant animals. Overall, these findings support the hypothesis that early pregnancy signaling alters the phenotype of immune cells in the peripheral blood and that there are differences in the peripheral immune response to pregnancy between cows and heifers. Because cows have lower conception rates than heifers, it is possible that a more proinflammatory immune status in peripheral blood may play a role in embryo loss.

Effects of parity and early pregnancy on peripheral blood leukocytes in dairy cattle

Subfertility remains a major problem in the dairy industry. Only 35-40% of high-yielding dairy cows and 55-65% of nonlactating heifers become pregnant after their first service. The immune system plays a critical role in the establishment of pregnancy. However, it can also create challenges for embryo survival and contribute to reduced fertility. We conducted 2 separate experiments to characterize changes in subsets of peripheral blood leukocytes (PBL) and their phenotype over the estrous cycle and early pregnancy in heifers and cows. We used flow cytometry and RT-qPCR to assess protein and mRNA expression of molecules important for immune function. We observed that monocytes and T cells were most affected by pregnancy status in heifers, whereas, CD8+ lymphocytes and natural killer (NK) cells were most affected during early pregnancy in cows. Changes in immune parameters measured appeared to be greater in heifers than cows including changes in expression of numerous immune function molecules. To test the hypothesis, we conducted a third experiment to simultaneously analyze the immunological responses to pregnancy between cows and heifers. We observed that cows had greater expression of proinflammatory cytokines and molecules associated with leukocyte migration and phagocytosis compared to heifers. Moreover, animals that failed to become pregnant showed altered expression of anti-inflammatory molecules. Overall, these findings support the hypothesis that early pregnancy signaling alters the proportions and functions of peripheral blood immune cells and differences between cows and heifers may yield insight into the reduced fertility of mature lactating dairy cows.

In vitro evaluation of ginsenoside Rg1 immunostimulating effect in bovine mononuclear cells

The aim of this study was to evaluate the immunomodulatory effect of ginsenoside Rg1 on mammary secretion and peripheral blood mononuclear cells (MSMC and PBMC, respectively). The mRNA expression of TLR2, TLR4 and selected cytokines were evaluated on MSMC after Rg1 treatment. Also, TLR2 and TLR4 protein expression was evaluated on MSMC and PBMC after Rg1 treatment. Phagocytic activity and capacity, ROS production and MHC-II expression were evaluated on MSMC and PBMC after Rg1 treatment and co-culture with Staphylococcus aureus strain 5011. Rg1 induced mRNA expression of TLR2, TLR4, TNF-α, IL-1β, IL-6 and IL-8 in groups treated with different concentrations and at different times in MSMC, and induced TLR2 and TLR4 protein expression in MSMC and PBMC. Rg1 increased phagocytic capacity and ROS production in MSMC and PBMC. Rg1 increased MHC-II expression by PBMC. However, Rg1 pre-treatment had no effect on cells co-cultured with S. aureus. In conclusion, Rg1 was able to stimulate several sensing and effector activities in these immune cells.