Protective effects of Bee pollen extract on the Caco-2 intestinal barrier dysfunctions induced by dextran sulfate sodium.

Bee pollen (BP) is a natural medicine from the hive with various potential health-promoting benefits, but until now there is no study to determine its protective roles in inflammatory bowel disease (IBD). The aim of this study was to reveal the in vitro gastrointestinal protective effects of BP against IBD using molecular and metabolic methods. Dextran sulfate sodium (DSS) challenged Caco-2 cell monolayers were applied to mimic intestinal epithelial cell dysfunctions and metabolic disorders. The pretreatment with BP extract rich in polyphenols ameliorated DSS-induced cell viability losses. It also exerted protective effects against intestinal barrier impairment by strengthening epithelial integrity and tight junction losses induced by DSS. BP up-regulated anti-oxidant (NQO1, Txnrd1, Nrf2) and down-regulated inflammatory (TNF-α and IL-6) mRNA expressions, in accompany with MAPK signaling inhibition. Furthermore, metabolomics analysis based on UPLC-Q-TOF/MS revealed that BP, and DSS treated Caco-2 cells have different metabolomic profiles, with significant changes on key metabolites involved in glycerophospholipid metabolism. Our results showed that BP has great therapeutic potential throughout the early stages of DSS-induced colitis.