Effect of recombinant Lactobacillus casei expressing interleukin‐10 in dextran sulfate sodium‐induced colitis mice

Objective To study the effect of recombinant L actobacillus casei ( L.casei ) expressing interleukin ( IL )‐10 combined with 5‐aminosalicylic acid (5‐ ASA ) in dextran sulfate sodium ( DSS )‐induced colitis mice. Methods Recombinant L . casei CECT 5276, which can secrete IL ‐10, was constructed. The length of colon tissue, disease activity index ( DAI ) and histological score ( HS ) of the mice were determined to evaluate the modeling and the effectiveness of L . casei . Real‐time polymerase chain reaction ( PCR ), Western blot and ELISA were used to determine the levels of nuclear factor kappa‐light‐chain‐enhancer of activated B cells ( NF ‐κ B ), peroxisome proliferator‐activated receptor ( PPAR )‐γ, interferon ( IFN )‐γ, transforming growth factor ( TGF )‐β and IL ‐10. Results Recombinant L . casei expressing IL ‐10 combined with 5‐ ASA was more effective than L . casei with 5‐ ASA . Among the three different concentrations of the recombinant L . casei , the highest concentration group (2 × 10 9 colony‐forming units/m L ) had the best effectiveness. Conclusions Recombinant L . casei combined with 5‐ ASA is effective in the treatment of DSS ‐induced colitis. The possible mechanism might be the blocking of the excessive activation of NF ‐κ B pathway, thus suppressing the release of inflammation‐related factors.