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

The proximal convoluted tubules of the kidney of white Wistar rats were examined. The animals were given Cladribine (2-CdA) subcutaneously at dosages of 0.07 mg/kg b.m./24 h for 7 days and 0.1 mg/kg b.m./24 h for 6 days in three courses with 5 weeks' break between each. The animals were decapitated 24 hours after the last dose of the drug and 4 weeks after the last dose. The kidney samples were taken for ultrastructural examination. Giving Cladribine at the dose of 0.1 mg/kg b.m./24 h for 7 successive days does not lead to instant changes in the ultrastructure of the proximal convoluted tubules. Changes noticed 4 weeks after Cladribine administration are the following: decrease in amount of mitochondria, the presence of numerous vacuoles, changes in the structure of the brush border, presence of numerous glycogen granules, and the presence of a diluted cytoplasm around the nucleus. Giving 2-CdA at the dose of 0.07 mg/kg b.m./24 h for 6 days in three courses leads to similar changes in proximal convoluted tubules with more extensive damages of the brush border. These were no more intensive after 4 weeks' break in Cladribine administration.