Induced endometritis in early lactation compromises production and reproduction in dairy cows

Analysis of blood biochemistry and non-targeted metabolomics of endometritis in dairy cows

The incidence of bovine endometritis, which has a negative impact on the reproduction of dairy cows, has been recently increasing. In this study, the differential markers and metabolites of healthy cows and cows with endometritis were analyzed by measuring blood biochemical indicators and immune factors using biochemical and enzyme-linked immunosorbent assay kits combined with nontargeted metabolomics. The LC-QTOF platform was used to evaluate the serum metabolomics of healthy cows and cows with endometritis after 21-27 days of calving. The results showed that glucose, free fatty acid, calcium, sodium, albumin, and alanine aminotransferase levels were significantly lower in the serum of cows with endometritis than in healthy cows (P < 0.05). However, the serum potassium, interleukin-1, interleukin-6, and tumor necrosis factor levels were significantly higher in cows with endometritis (P < 0.05). In addition, the serum metabolome data analysis of the two groups showed that the expression of 468 metabolites was significantly different (P < 0.05), of which 291 were upregulated and 177 were downregulated. These metabolites were involved in 78 metabolic pathways, including amino acid, nucleotide, carbohydrate, lipid, and vitamin metabolism pathways; signal transduction pathways, and other biological pathways. Taken together, negative energy balance and immune activation, which are related to local abnormalities in amino acid, lipid, and carbohydrate metabolism, were the important causes of endometritis in dairy cows. Metabolites such as glucose, carnosine, dehydroascorbic acid, L-malic acid, tetrahydrofolic acid, and UDP-glucose may be used as key indicators in the hematological diagnosis and treatment of endometritis in dairy cows.

Microbial responses and changes in metabolic products in bovine uteri infected with Staphylococcus aureus

There is mounting evidence that the uterine microbiota has an important role in the pathogenesis of endometritis, with invasion of pathogenic bacteria being a main cause of uterine microbial imbalance. However, mechanisms of uterine microbiota resistance to pathogen invasion remain unclear. In this study, an intrauterine infusion of Staphylococcus aureus was used as a bovine endometritis model; it significantly increased abundance of pathogenic bacteria (Streptococcus, Helccoccus, Fusobacterium, and Escherichia-Shigella) and significantly decreased abundance of probiotics (Allstipes, Bacteroides, Phascolarctobacterium, Romboutsia, and Prevotella). In addition, the metabolite aloe-emodin was positively correlated with Prevotella and based on combined analyses of omics and probiotics, the presence of its metabolite aloe-emodin in the uterus at least partially resisted Staphylococcus aureus invasion. Therefore, Aloe-emodin has potential for regulating microbial structure and preventing endometritis.

Enhanced expression of miR-204 attenuates LPS stimulated inflammatory injury through inhibiting the Wnt/β-catenin pathway via targeting CCND2

One of the most common bacterial diseases of the reproductive system in dairy cows is endometritis, which will cause huge economic loss. Here, we investigate the mechanisms of miR-204 on LPS-stimulated endometritis in vitro and in vivo. Experiments displayed that the expression of miR-204 was lower in bovine uterine tissue samples or bovine endometrial epithelial cell line (BEND) that stimulated by LPS. Compared with the negative group, miR-204 treatment significantly suppressed the production of proinflammatory factors and the Wnt/β-catenin pathway activation. Additionally, the result of the dual luciferase assay showed that miR-204 targeted cyclin D2. More importantly, up-regulation of miR-204 alleviated LPS induced uterine injury was confirmed in vivo studies. Molecular experiments indicated that the expression level of tight junctional proteins Claudin3 and cadherin1 were both enchanced by miR-204 treatment. Accordingly, miR-204 may serve as a new measure to prevent and treat endometritis caused by LPS.