Lactobacillus Rhamnosus GR-1 Ameliorates Trueperella Pyogenes–Induced Barrier Dysfunction of Bovine Endometrial Epithelial Cells

Trueperella pyogenes is a common opportunistic pathogen which is one of the main causes of postpartum endometritis in dairy cows. As a substitute for antibiotics, the probiotic Lactobacillus rhamnosus GR-1 has been used in a wide range of clinical treatments. Our experiments were designed to establish a model of anti-damage which LGR-1 was used to protect bovine endometrial epithelial cells (BEECs) from inflammatory damage and cell destruction caused by T. pyogenes. Increased expression of NLRP3 inflammasomes and cytokines was observed following T. pyogenes challenge, but this increase was relieved by LGR-1 pretreatment. Immunofluorescence and Western blot analyses revealed that T. pyogenes infection also results in the damage of tight junction proteins in BEECs. The expression levels of Claudin-1, Occludin, and ZO-1 were decreased in cells only infected with T. pyogenes but not in cells pretreated with LGR-1. Moreover, the detection of the anti-apoptotic protein Bcl-2 and apoptotic proteins BAX, cytochrome c, as well as the activating effector caspase-3 revealed that T. pyogenes induced apoptosis of BEECs, which was also confirmed by DAPI staining to observe the morphological changes of the nuclei of cell apoptosis and by TUNEL staining to locate the cells undergoing apoptosis. Our data indicate that LGR-1 ameliorates the T. pyogenes–induced barrier dysfunction of BEECs and pre-application of LGR-1 could be an effective strategy for controlling T. pyogenes infection.