Protective effect of aged garlic extract on the small intestinal damage of rats induced by methotrexate administration.

The methotrexate (MTX) administration to rats causes the damage of small intestine. The small intestinal damage was evaluated by measuring the intestinal permeability of the poorly absorbable compound, fluorescein isothiocyanate (FITC)-labeled dextran (average molecular weight, 4,400) (FD-4) using the in vitro everted intestine technique and by determining the FD-4 that appeared in plasma using the in situ closed loop intestine technique. The MTX administration to rats fed with the standard laboratory diet increased the small intestinal permeability of FD-4 due to the damage of the small intestine. Interestingly, the permeability of FD-4, when MTX was administered to rats fed with the aged garlic extract containing diet, was depressed almost to the level of control rats without the MTX treatment. The present study showed that the aged garlic extract protected the small intestine from the damage induced by the action of MTX on the crypt cells.