Mangen Zhao

Histopathological evidence that spermatogonia are the target cells of 2-bromopropane.

To confirm the target cell of 2-bromopropane within the testis, 1355 mg/kg of 2-bromopropane was subcutaneously injected to rats for 1-5 days and the numbers of spermatogonia and spermatocytes were examined 6 h after each last injection. The number of stage I spermatogonia decreased after the first 2-bromopropane injection and the number of spermatogonia at the other stages also decreased following repetitive injection. The number of these spermatogonia decreased further by the repetition of 2-bromopropane injection. In addition, the delay in mitotic division of type B spermatogonia was frequently observed after the fifth 2-bromopropane injection. The number of stage I pachytene spermatocytes also decreased slightly after the first 2-bromopropane injection, although it did not decrease further following repetitive injection. Therefore, we concluded that spermatogonia are the target cells of 2-bromopropane in rats.

Testicular toxicity evaluation of arsenic-containing binary compound semiconductors, gallium arsenide and indium arsenide, in hamsters

The testicular toxicities of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were examined by repetitive intratracheal instillation using hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) were instilled twice a week a total of 16 times and InAs (7.7 mg/kg) was instilled a total of 14 times. GaAs caused testicular spermatid retention and epididymal sperm reduction, though the degrees were less severe than those in rats shown in our previous experiment. InAs and As2O3 did not show any testicular toxicities. Serum arsenic concentration in GaAs-treated hamsters was less than half of that in As2O3-treated hamsters in which no testicular toxicities were found. Serum molar concentration of gallium was 32-times higher than that of arsenic in GaAs-treated hamsters. Therefore gallium may play a main role in the testicular toxicity of GaAs in hamsters.

Histopathological Changes of the Testis in Rats Caused by Subcutaneous Injection of 2-Bromopropane.

Histopathological Changes of the Testis in Rats Caused by Subcutaneous Injection of 2‐Bromopropane: Minoru Omura, et al. Department of Hygiene, Kyushu University—Mature male rats were injected subcutaneously with 1,355 mg/kg of 2‐bromopropane five days a week for two weeks. In addition to the routine examinations concerning the effect on male reproductive system, we carried out an evaluation of change in the numbers of various types of germ cells in the seminiferous tubule at stages I, V, VII, X and XII to clarify germ cells which were affected by 2‐bromopropane. 2‐Bromopropane caused mild atrophy of the seminal vesicle, but did not show any adverse effects on spermatid/sperm count, sperm motility or sperm morphology. In the histopathological examination of the testis, the numbers of spermatogonia, preleptotene spermatocyte, leptotene spermatocyte, zygotene spermatocyte and pachytene spermatocyte at stages I and V decreased in the rats treated with 2‐bromopropane. However, the numbers of pachytene spermatocyte at stages VII, X and XII and round spermatids in these rats were comparable with those in control rats. In two weeks, spermatocytes develop to pachytene spermatocyte at stage VII or more developed germ cells in rats. Therefore, it seemed likely that 2‐bromopropane had no adverse effects on spermatocytes but affected spermatogonia, assuming that 2‐bromopropane affected germ cells immediately after the injection. In conclusion, we estimated that spermatogonia were the target cells of 2‐bromopropane in the testis in rats.