Disposal of Dyes by Proximal Tubule Cells of Chick Mesonephros in Tissue Culture

Dyestuffs have been used extensively for studying renal activity. However, from evidence in the literature there seems to be no rule governing intake of the various kinds of dyes by the tubule cells. For example, some lipoid-soluble dyes, to which cells are known to be permeable, are not passed into the tubular urine while, of the lipoid-insoluble dyes, some are known to be passed into the urine and others are not, with no apparent reference to their chemical constitution.

By means of the tissue culture method we have been engaged in testing the behavior of the proximal tubules to a series of dyes. Aqueous solutions of the dyes in various concentrations are mixed with the usual tissue culture medium in which are planted fragments of the functioning mesonephros of a 9-11-day chick. This method affords a means of studying the problem in a more direct manner than hitherto possible. Moreover, it enables one to restrict the problem to the proximal tubules which remain alive and functional for days in the explant. Isolated segments of the tubules regenerate their cut ends and become converted into closed sacs into which the progressive accumulation of color can be observed microscopically.

In this report the results of experiments are given on the use of the following dyes. They are the lipoid-soluble basic dyes, Neutral red, No. 825; and Nile blue sulfate, No. 913; which are in general use as vital stains, and the lipoid-insoluble acid dyes, Xylene cyanol FF, No. 715∗; Amaranth, No. 184; Acid fuchsin, No. 692; and Orange G No. 27. These acid dyes resemble the sulphonephthaleins in forming highly dissociated, sulfonated compounds in aqueous solutions but differ from them in not being passed by the tubular epithelium into the tubular urine.