Rice prolamin extract ameliorates acute murine colitis by inhibiting nuclear factor-kappa B and modulating intestinal apoptosis and cell proliferation.

We investigated the impact of rice prolamin extract ( RPE) on lipopolysaccharide ( LPS)-induced nuclear factor ( NF)-κ B signalling in intestinal epithelial cells and macrophages, and determined the therapeutic efficacy of RPE in acute murine colitis. The effect of RPE on LPS-induced NF-κ B signalling and proinflammatory gene expression was evaluated by reverse transcription-polymerase chain reaction ( RT- PCR), Western blotting, immunofluorescence and electrophoretic mobility shift assay ( EMSA). The in-vivo efficacy of RPE was assessed in mice with 3% dextran sulphate sodium ( DSS)-induced colitis. Apoptotic and cellular proliferative activities were evaluated by immunostaining with cleaved caspase-3 and proliferating cell nuclear antigen ( PCNA) antibodies. RPE inhibited LPS-induced expression of monocyte chemotactic protein ( MCP)-1, interleukin ( IL)-6 and tumour necrosis factor ( TNF)-alpha and LPS-induced NF-κ B signalling in intestinal epithelial cells and macrophages. RPE-fed, DSS-exposed mice showed less weight loss, longer colon length and lower histological score compared to control diet-fed, DSS-exposed mice. Immunostaining analysis revealed a significant decrease of cleaved caspase-3 positive cells in RPE-fed, DSS-exposed mice compared to DSS-exposed mice. Also, the number of PCNA-positive cells within intact colonic crypts decreased significantly in RPE-fed, DSS-exposed mice compared to control diet-fed, DSS-exposed mice. DSS-induced NF-κ B signalling was inhibited by RPE. RPE ameliorates intestinal inflammation by inhibiting NF-κ B activation and modulating intestinal apoptosis and cell proliferation in an acute murine colitis. [ABSTRACT FROM AUTHOR]