[Fluorescence microscopy of the absorption and disappearance of adriamycin through the bladder epithelium in the rat].

The absorption and disappearance of adriamycin (ADM) through the bladder epithelium in the rat was investigated using a fluorescence microscope. In the absorption study in vitro, ADM permeated through the epithelium into the lamina propria or the inner layer of the muscle within 15 minutes after instillation, showing no further infiltration into the deeper part of the bladder wall. In addition, fluorescence histological evidence for the uptake of ADM by the endothelial cells of the blood vessels in the lamina propria suggested a systemic diffusion of ADM to the whole blood by blood circulation. These data coincided well with the absorption study in vivo. On the other hand, ADM once absorbed in the bladder wall disappeared from the lamina propria or the inner layer of the muscle and was confined only in the epithelium at 60 min after the excretion of ADM. The intensity of ADM fluorescence then decreased gradually with time elapsed. No ADM fluorescence was recognized in the bladder tissue 48 hr later. In the absorption study with the BBN induced rat bladder tumor, ADM permeated into all the cells of papillary tumor within 5 minutes of instillation. The fluorescence histological method used in the present study is harmless and may readily be applicable to the pharmacodynamic study of ADM in human bladder tumors. This method proves to be a promising approach to the development of an ideal instillation therapy effective on bladder tumor cells without side-effects.