Testicular Toxicity of Gallium Arsenide, Indium Arsenide, and Arsenic Oxide in Rats by Repetitive Intratracheal Instillation

The testicular toxicities of two compound semiconductor materials,gallium arsenide (GaAs) and indium arsenide (InAs), and arsenicoxide (As₂O₃) were examined in rats by repetitive intratrachealinstillation of these substances in suspension twice a week,a total of 16 times. A single instillation dose was 7.7 mg/kgin the GaAs and the InAs groups and 1.3 mg/kg in the As₂O₃ group.A significant decrease in sperm count and significant increasein the proportion of morphologically abnormal sperm were foundin the epididymis in the GaAs group. Especially, abnormal spermwith a straight head increased markedly in this group. In theGaAs–treated rats, there was 40-fold increase in the degeneratinglate elongated spermatids at the postspermiation stages, stagesIX, XI, and XI. From these results, it is indicated that GaAsdisturbed the spermatid head transformation at the late spermiogenicphases and caused spermiation failure. InAs caused a sperm countdecrease in the epididymis, though its testicular toxicity wasrelatively weak compared with that of GaAs. As₂O₃, a probabledissolution arsenic product of GaAs and InAs in vivo, did notshow any testicular toxicities in this study. It seems likelythat, along with arsenics, gallium and indium play a role inthe testicular toxicities of GaAs and InAs.