8-Methoxypsoralen protects bovine mammary epithelial cells against lipopolysaccharide-induced inflammatory injury via suppressing JAK/STAT and NF-κB pathway

Bovine mastitis is the most common disease in dairy cattle. Bacterial infections are the main cause of mastitis. Lipopolysaccharide (LPS), a major structural component of the cell wall of Escherichia coli, is a good inducer used to replicate inflammation models. 8-Methoxypsoralen (8-MOP), a formerly considered photosensitizing agent, has been used in immunotherapy. This study investigated the protective effects of 8-MOP on LPS-induced inflammatory injury in bovine mammary epithelial cells (BMECs). LPS treatment (50 μg/mL for 12 hr) caused a decrease in cell viability, morphological damage, and cell apoptosis. Pretreatment with 8-MOP at concentrations of 25 and 50 μg/ml significantly attenuated LPS-induced inflammation in BMECs. qRT-PCR analysis revealed that the messenger RNA expression of inflammatory cytokines and chemokine (interleukin-1β [IL-1β], IL-6, tumor necrosis factor-α, and IL-8) was suppressed by 8-MOP in LPS-stimulated BMECs. Western blot analysis showed that 8-MOP could also reduce the protein levels of cyclooxygenase-2 and promote the translocation of high-mobility group box 1 from the nucleus to cytoplasm. Furthermore, the anti-inflammatory property of 8-MOP was mediated by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells activation and STAT1 phosphorylation. Taken together, 8-MOP could protect cells from inflammatory injury induced by LPS, and may be a potential agent against bovine mastitis.