A new technique for preparing precision-cut slices from small intestine and colon for drug biotransformation studies

Introduction: A new technique was developed to prepare precision-cut slices from small intestine and colon with the object of studying the biotransformation of drugs in these organs. Methods: Rat intestinal slices were prepared in two different ways. In the first method, slices were punched out of the small intestine. In the second method, precision-cut slices were made from agarose-filled and -embedded intestines, using the Krumdieck tissue slicer. This method was also applied to colon tissue. Viability of the slices was determined by analysis of intracellular ATP and RNA levels and morphology. Drug metabolizing activity was studied using lidocaine, testosterone, and 7-ethoxycoumarin (7-EC) as phase I substrates, and 7-hydroxycoumarin (7-HC) as a phase II substrate. Results: Precision-cut slices made from agarose-filled and -embedded intestine better preserved ATP levels than tissue that was punched out of the intestinal wall. After 24 h of incubation, morphology in precision cut-slices showed was quite well preserved while punched out tissue was almost completely autolytic after incubation. In addition, total RNA amount and quality was much better maintained in precision-cut slices, when compared to punched out tissue. Both intestinal slices and punched-out tissue showed high, and comparable, phase I and phase II biotransformation activities. Discussion: It is concluded that preparing precision-cut 0.25 mm slices out of agarose-filled and -embedded intestine provides an improvement, compared with punched-out tissue, and that both intestinal and colon slices are useful preparations for in vitro biotransformation studies.