Effects of male sexual maturity of reproductive endpoints relevant to DART studies in Wistar Hannover rats
| Autor: | Ryohei Yokoi, Tomoya Onozato, Yoshimasa Maruyama, Junji Kuroda, Hiroshi Kusama, Dianne M. Creasy, Ikuro Takakura, Toru Tamura, Tomonobu Chino, Toru Tahara, Yukari Terashima |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Aging medicine.medical_specialty media_common.quotation_subject Physiology Fertility Genitalia Male Biology Toxicology Pregnancy Internal medicine Toxicity Tests medicine Animals Humans Sexual maturity Sexual Maturation Rats Wistar Spermatogenesis Sperm motility media_common Reproduction Epididymis Sperm Rats Specific Pathogen-Free Organisms medicine.anatomical_structure Endocrinology Female Reproductive toxicity |
| Zdroj: | The Journal of Toxicological Sciences. 39:269-279 |
| ISSN: | 1880-3989 0388-1350 |
| Popis: | Wistar Hannover rats have been utilized as one of major strains in regulatory toxicology studies. This study was performed to verify the appropriate age of male sexual maturity in the development and reproductive toxicity (DART) study in Wistar Hannover rats (RccHan:WIST) by comparing reproductive endpoints between 8, 10 and 12 weeks of ages. Although fertility showed a tendency toward decrease in 8-week-old males, copulation index was not different among three ages. Testis weights reached a plateau at 10 weeks of age, whereas weights of other reproductive organs developed until 12 weeks of age. Indices of spermatogenesis (sperm motility, number of sperm in the epididymis and testis and contents of morphologically abnormal sperm) showed age-related progress and did not fully develop except for 12-week-old. For histology, epididymal tubules in 8-week-old animals showed immaturity with tall epithelium. At cesarean section, dams mated with 8-week-old males showed high incidence of preimplantation loss and the number of live fetuses was less than 10. In conclusion, although reproductive performance attained maturity by age of 10 weeks, spermatogenesis was not fully established at 10-week-old, which could result in a low fertility index. Therefore, we recommend that Wistar Hannover male rats at 12-week-old or older are used to conduct DART study properly and evaluate any adverse effects on dams and embryo-fetal development. |
| Databáze: | OpenAIRE |
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