Histomorphology of renal proximal convoluted tubules of kidney of experimental animals after Cladribine (2-CdA) administration.

The proximal convoluted tubules of the kidney of the white Wistar rats were examined. The animals were given Cladribine (2-CdA) sub-cutaneously at the dose: 0.07 mg/kg b.w./24 h for 7 days and 0.1 mg/kg b.w./24 h for 6 days in 3 courses, with 5 weeks' break between each. The animals were killed in each instance 24 hours after the last dose of the drug, and 4 weeks after the last dose. The kidney's samples were taken for histological and histochemical examination and were stained with hematoxylin and eosin, using the Masson's, the PAS's, and the Feulgen's method. In experimental group I, we observed few changes (in comparison to the control group): cells of the epithelium of some of the proximal convoluted tubules were however, puffy. In a few tubules we observed some unknown substance and the lumen of some of these tubules was narrowed. In experimental group II, a few proximal convoluted tubules and their lumen were wider with an unknown substance within. We also observed hydropic degeneration. The brush border of these tubules was a little lower than in control group. In experimental group III, the cells of the epithelium of proximal convoluted tubules rested on a thicker basement membrane, the lumen of most of the proximal convoluted tubules being narrow and filled with some unknown substance. In experimental group IV, the lumen of the tubules was a little wider, and the epithelial cells were smaller than in the control group, thus the lumen of the tubules was wider. In the cytoplasm of epithelial cells we observed numerous PAS(+) granules. The low brush border appeared damaged.