Changes in the testicular damage caused by indium arsenide and indium phosphide in hamsters during two years after intratracheal instillations

Changes in the testicular damage caused by indium arsenide (InAs) and indium phosphide (InP) was examined during two yr after repetitive intratracheal instillations in hamsters. In this study, 4.0 mg/kg body weight/day of InAs or 3.0 mg/kg body weight/day of InP was instilled intratracheally twice weekly for eight wk. A single instillation dose of indium was 2.4 mg/kg body weight in both groups. Testicular damage was evaluated 0, 8, 16, 40, 64 and 88 wk after the last instillation. Both InAs and InP were proved to be definite testicular toxicants. Both materials decreased reproductive organ weight and caudal sperm count, and caused severe histopathologic changes in the testes. InAs-induced testicular damage was always more serious than InP-induced testicular damage. The serum indium concentration in the InAs group was always higher than that in the InP group, and indium was probably a toxic element in both materials. In the histopathologic examination, vacuolization of seminiferous epithelium was frequently observed as an early histopathologic change and spermatogonia remained in general even in the seminiferous tubules with severe histopathologic changes in both groups. It is therefore estimated that Sertoli cells, not stem cell spermatogonia, were the target cells of these indium-containing compound semiconductor materials. The threat of InAs and InP to male reproduction was proved in this study. We concluded that male reproductive disorders should not be overlooked when severe exposure to indium-containing compound semiconductor materials is apparent in human subjects.