Glutathione transferases (
GSTs) play a central role in the cellular defense against harmful endogenous compounds and
xenobiotics in mouse and man. The gastrointestinal channel is constantly exposed to bacteria, bacterial products, and
xenobiotics. In the present study the distribution of alpha, mu, and pi class
GSTs was examined immunohistologically in the colon of conventional and germ-free (GF) mice subjected to experimental
colitis. The tissues samples were from conventional mice with and without
colitis induced by
dextran sulfate sodium (DSS); GF mice treated with DSS or
carrageenan; and GF mice inoculated with normal mouse bacterial flora as well as with Lactobacillus GG. In conventional as well as in GF mice the mu and pi class
GSTs showed reduced intestinal expression when
colitis was induced. In con-rast, the level of
GSTs reacting with
antibodies directed against the alpha class, in particular mGST A4-4, was elevated after induction of
inflammation. Of special interest is mGST A4-4 because of its high catalytic activity with toxic products of lipid peroxidation. In the colon of conventionalized GF mice that were given mouse intestinal flora, the mGST A4-4 expression was increased with time for several weeks, but then showed a decrease to a normal level. Additionally, the inoculation of GF mice with Lactobacillus GG induced all the intestinal
GSTs studied.