Study on the therapeutic effect of <i>Viola yedoensis</i> and <i>Leonurus japonicus</i> on bovine endometritis

Endometritis in dairy cows has become a key challenge in the field of animal reproductive health. Currently, the primary treatment method is using antibiotics. However, antibiotics could induce pathogen resistance and the presence of drug residues. Traditional Chinese medicine has good advantages in the treatment of endometritis in dairy cows. This study aims to investigate the therapeutic effect of Viola yedoensis and Leonurus japonicus (TCMF) on endometritis in dairy cows. Firstly, LPS-induced cell inflammation model was established to evaluate the anti-inflammatory effects of TCMF, and then rat model of endometritis was constructed to preliminarily assess its therapeutic effects. Subsequently, based on mass spectrometry and network pharmacology, the mechanisms of TCMF in treating endometritis were investigated. Finally, clinical observations were performed to assess the therapeutic effects of TCMF on bovine endometritis. The results showed that TCMF significantly reduced IL-1β, IL-6, IL-8, and IL-18 mRNA levels compared to the LPS group (P < 0.001). Compared to the model group, TCMF significantly reduced the uterine index and bacterial load in rats (P < 0.05). Additionally, TCMF significantly reduced IL-1β, IL-6, and TNF-α protein levels (P < 0.001) and decreased the protein expression levels of TNF, PTGS2, and CASP3 (P < 0.01). Compared to the bovine endometritis group, TCMF significantly reduced the scoring of uterine discharge, the number of PMNs, and the bacterial load (P < 0.001), while increasing the levels of albumin (ALB) and superoxide dismutase in the blood (P < 0.01), the cure rate of endometritis in dairy cows could reach up to 80%. Metabolomics analysis revealed upregulation of cortisol in the serum of treated cows. These results indicated that Viola yedoensis and Leonurus japonicus had a positive therapeutic effect on endometritis, and exerted effect through TNF signaling pathway, which could replace the antibiotics in a certain extent.