Circulating and endometrial cell oxidative stress in dairy cows diagnosed with metritis

Saliva as a Potential Source of Biomarkers in Cows with Metritis: A Pilot Study

Metritis affects 5-20% of cows after parturition, negatively impacting animal welfare and the profitability of dairy farms, increasing culling rates and costs, and decreasing productivity and reproduction rates. This study compared the results of a comprehensive biochemical panel consisting of 25 salivary and 31 serum analytes between healthy cows (n = 16) and cows with metritis (n = 12). Descriptive parameters such as depression, rectal temperature, body condition score (BCS), heart rate, respiratory rate, mucous color, ruminal motility, vaginal discharge, milk production, and complete hematology analyses were also assessed for comparative purposes. The biochemistry analytes comprised five analytes related to stress, five to inflammation, five to oxidative status, and nineteen to general metabolism. The two-way ANOVA analysis revealed that, in saliva, eight biomarkers (lipase, adenosine deaminase (ADA), haptoglobin (Hp), total proteins, g-glutamyl transferase (gGT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and creatine kinase (CK)) were significant higher in cows with metritis. In serum, eight biomarkers (ADA, Hp, serum amyloid A (SAA), fibrinogen, ferritin, AOPPs/albumin ratio, non-esterified fatty acids (NEFAs), and bilirubin) were significantly higher in cows with metritis, whereas six (total esterase (TEA), albumin, urea, lactate, phosphorus, and calcium) were lower. Of the total number of 23 biomarkers that were measured in both saliva and serum, significant positive correlations between the two biofluids were found for six of them (Hp, FRAP, CUPRAC, AOPPs, urea, and phosphorus). Urea showed an R = 0.7, and the correlations of the other analytes were weak (R < 0.4). In conclusion, cows with metritis exhibited differences in biomarkers of stress, inflammation, cellular immune system, and general metabolism in both salivary and serum biochemistry profiles. These changes were of different magnitudes in the two biofluids. In addition, with the exception of ADA and Hp, the analytes that showed changes in the saliva and serum profiles of cows affected by metritis were different. Overall, this report opens a new window for the use of saliva as potential source of biomarkers in cows with metritis.

The mammosphere-derived epithelial cell secretome modulates neutrophil functions in the bovine model

Background

Innovative therapies against bacterial infections are needed. One approach is to focus on host-directed immunotherapy (HDT), with treatments that exploit natural processes of the host immune system. The goals of this type of therapy are to stimulate protective immunity while minimizing inflammation-induced tissue damage. We use non-traditional large animal models to explore the potential of the mammosphere-derived epithelial cell (MDEC) secretome, consisting of all bioactive factors released by the cells, to modulate host immune functions. MDEC cultures are enriched for mammary stem and progenitor cells and can be generated from virtually any mammal. We previously demonstrated that the bovine MDEC secretome, collected and delivered as conditioned medium (CM), inhibits the growth of bacteria in vitro and stimulates functions related to tissue repair in cultured endothelial and epithelial cells.

Methods

The immunomodulatory effects of the bovine MDEC secretome on bovine neutrophils, an innate immune cell type critical for resolving bacterial infections, were determined in vitro using functional assays. The effects of MDEC CM on neutrophil molecular pathways were explored by evaluating the production of specific cytokines by neutrophils and examining global gene expression patterns in MDEC CM-treated neutrophils. Enzyme linked immunosorbent assays were used to determine the concentrations of select proteins in MDEC CM and siRNAs were used to reduce the expression of specific MDEC-secreted proteins, allowing for the identification of bioactive factors modulating neutrophil functions.

Results

Neutrophils exposed to MDEC secretome exhibited increased chemotaxis and phagocytosis and decreased intracellular reactive oxygen species and extracellular trap formation, when compared to neutrophils exposed to control medium. C-X-C motif chemokine 6, superoxide dismutase, peroxiredoxin-2, and catalase, each present in the bovine MDEC secretome, were found to modulate neutrophil functions.

Conclusion

The MDEC secretome administered to treat bacterial infections may increase neutrophil recruitment to the site of infection, stimulate pathogen phagocytosis by neutrophils, and reduce neutrophil-produced ROS accumulation. As a result, pathogen clearance might be improved and local inflammation and tissue damage reduced.

Reactive Oxygen Species Damage Bovine Endometrial Epithelial Cells via the Cytochrome C-mPTP Pathway

After parturition, bovine endometrial epithelial cells (BEECs) undergo serious inflammation and imbalance between oxidation and antioxidation, which is widely acknowledged as a primary contributor to the development of endometritis in dairy cows. Nevertheless, the mechanism of oxidative stress-mediated inflammation and damage in bovine endometrial epithelial cells remains inadequately defined, particularly the molecular pathways associated with mitochondria-dependent apoptosis. Hence, the present study was designed to explore the mechanism responsible for mitochondrial dysfunction-induced BEEC damage. In vivo, the expressions of proapoptotic protein caspase 3 and cytochrome C were increased significantly in dairy uteri with endometritis. Similarly, the levels of proapoptotic protein caspase 3, BAX, and cytochrome C were markedly increased in H2O2-treated BEECs. Our findings revealed pronounced BEEC damage in dairy cows with endometritis, accompanied by heightened expression of cyto-C and caspase-3 both in vivo and in vitro. The reduction in apoptosis-related protein of BEECs due to oxidant injury was notably mitigated following N-acetyl-L-cysteine (NAC) treatment. Furthermore, mitochondrial vacuolation was significantly alleviated, and mitochondrial membrane potential returned to normal levels after the removal of ROS. Excessive ROS may be the main cause of mitochondrial dysfunction. Mitochondrial permeability transition pore (mPTP) blockade by cyclophilin D (CypD) knockdown with CSA significantly blocked the flow of cytochrome C (cyto-C) and Ca2+ to the cytoplasm from the mitochondria. Our results indicate that elevated ROS and persistent opening of the mPTP are the main causes of oxidative damage in BEECs. Collectively our results reveal a new mechanism involving ROS-mPTP signaling in oxidative damage to BEECs, which may be a potential avenue for the clinical treatment of bovine endometritis.