Viability, Prostaglandin E₂ Production, and Protein Handling in Normal and Inflamed Human Colonic Mucosa Cultured for up to 48 h in Vitro

Abstract

Human colonic mucosa obtained from colon cancer resections ('normal') and from colectomies owing to ulcerative colitis (inflamed) were cultured for up to 48 h in vitro. The ³H-leucine incorporation in normal tissue decreased to 52% (p < 0.001) at 48 h compared with 24 h. The protein synthesis in normal but not in inflamed explants was significantly (p < 0.01) improved at 48 h, reaching 72% of the 24-h value, on additions of insulin and the protease inhibitors aprotinin, soyabean trypsin inhibitor, and N^α-tosyl-L-lysine chloromethyl ketone to the culture medium. Inflamed tissue had significant protein losses of 15% after 24 h and 29% after 48 h in culture, and the excretion of precipitable ³H-leucine-labelled proteins could be as high as 20%/24 h. A slight protein loss was observed in normal tissue after 48 h in culture, but the excretion of labelled proteins was very low (3%). The prostaglandin E₂ (PGE₂) production in both normal and inflamed tissue displayed an increasing non-linear pattern with time in culture, with higher values for inflamed tissue. The PGE₂ release profiles and the differences in basic protein metabolism between normal and inflamed human colonic biopsy specimens in culture might reflect important characteristics of the inflammatory process.

Key Words:

• Human colon
• inflammation
• organ culture
• prostaglandin E₂
• protein synthesis
• rabbit colon
• viability