Preparation and characterization of viable epithelial cells from rabbit distal colon

A preparation of viable epithelial cells, suitable for transport studies, was prepared from rabbit distal colon. Enzymatic digestion of scraped mucosa liberated a population of intact colonic glands that were dissociated into cells by gentle agitation in culture medium. Metabolism of [14C]glucose was constant over 2 h and was inhibited 70% by 1 mM ouabain. Cells were loaded with the trapped, pH-sensitive fluorescent dye 2'-7'-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxy methyl ester and leaked 0.1% of the dye per minute. Cell pH was 7.21 +/- 0.03 (SE) (n = 15) in pH 7.4 Ringer medium. Intracellular potassium concentration, as measured by a nigericin null-point technique, was 128 +/- 8 mM. Plasma membrane potential measured with the potential-sensitive fluorescent dye 3,3-dipropylthiadicarbocyanine iodide was -52 +/- 2 mV. Recovery of intracellular pH in acid-loaded cells occurred after exposure to sodium-containing medium and was inhibited by 5 x 10(-4) M amiloride. It is concluded that viable epithelial cells can be prepared from rabbit distal colon with relative simplicity and in high yield. These cells are suitable for measurement of intracellular pH and membrane potential and are thus a convenient model system for study of colonic cell physiology.