Testicular Mineralization in KK-Ay Mice Treated with an Oxovanadium Complex

Vanadium has potential for use in diabetes therapy. Many investigators have reported toxic effects of inorganic vanadium salts; however, there are few reports on toxic effects of oxovanadium(VO(2+)) complexes. Therefore, we studied VO(2+) toxicity by examining histological changes and measuring the vanadium concentration in the testis after repeated oral administration of bis(1-oxy-2-pyridine-thiolato)oxovanadium(VO(2+)) (VO(opt)2) for 2 or 4 weeks in KK-A(y) mice. Severe mineralization and degeneration/necrosis of the seminiferous tubules were detected after either 2 or 4 weeks of administration. Vacuolar changes in Sertoli cells and the seminiferous epithelia, and hyperplasia of Leydig cells were observed in the testes of some animals. Vanadium concentrations in the mineralized testis were much higher than those in the testis of untreated KK-A(y) mice. These results represent the first report of the possibility for seminiferous tubules mineralization induced by VO(opt)2 administration. Therefore, our research provides important information about the potentially toxic effects of VO(2+) complexes.