TLR4 and mastitis: Compared with the normal group, the mastitis group showed significant upregulation of the mRNA levels of the LPS-mediated pathway-related genes, TLR4 and MyD88, as well as increased levels of inflammatory cytokines, TNF-α, IL-8 and TGF-β1; the expression of p65 and Snail mRNA were also increased (p < 0.05; Figure 5A,B).