title: Histological Development of Male Reproductive Organs in Microminipigs.
abstract: Microminipigs are becoming increasingly attractive alternatives for various experimental applications, such as general toxicology studies, owing to their manageable size. However, there are limited studies on the male reproductive organs of microminipigs, particularly on the histological aspects of sexual maturity. To clarify the development of male reproductive organs, 35 male microminipigs, aged 0 to 12 months, were used in this study. Histological and histomorphological evaluation was performed based on spermatogenic development, measurement of tubular structure in testes and epididymides, and histological progress of accessory glands. In addition, spontaneous testicular changes were quantitatively assessed. Histologically, male microminipigs sexually matured around 4.5 months of age, when spermatogenesis in testes and structural development in genital organs were completed. Spontaneous testicular changes occurred in all the animals investigated. Multinucleated giant cell was most commonly observed, followed by hypospermatogenesis and tubular atrophy/hypoplasia. However, the number of affected tubules was less than 1% in testes after 4.5 months of age, suggesting that the influence of these changes on evaluation of toxicity studies may be minimal. It is preferable to use sexually mature animals in toxicology studies; therefore, the information obtained by the present study will be helpful for future toxicity evaluations in microminipigs.
authors: 1 Swine and Poultry Department, Shizuoka Prefectural Research Institute of Animal Industry, Swine and Poultry Research Center, Kikugawa, Shizuoka, Japan.
authors: Akihisa
authors: A
authors: Kangawa
authors: 1 Swine and Poultry Department, Shizuoka Prefectural Research Institute of Animal Industry, Swine and Poultry Research Center, Kikugawa, Shizuoka, Japan.
authors: Masayoshi
authors: M
authors: Otake
authors: 1 Swine and Poultry Department, Shizuoka Prefectural Research Institute of Animal Industry, Swine and Poultry Research Center, Kikugawa, Shizuoka, Japan.
authors: Satoko
authors: S
authors: Enya
authors: 2 Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
authors: Toshinori
authors: T
authors: Yoshida
authors: 1 Swine and Poultry Department, Shizuoka Prefectural Research Institute of Animal Industry, Swine and Poultry Research Center, Kikugawa, Shizuoka, Japan.
authors: Masatoshi
authors: M
authors: Shibata
mesh_terms: D000818:Animals; D004822:Epididymis / Q000033:anatomy & histology* / Q000254:growth & development; D008297:Male; D009929:Organ Size; D012671:Seminiferous Tubules / Q000033:anatomy & histology* / Q000254:growth & development; D012741:Sexual Maturation; D013552:Swine / Q000033:anatomy & histology* / Q000254:growth & development; D013556:Swine, Miniature / Q000033:anatomy & histology* / Q000254:growth & development; D013737:Testis / Q000033:anatomy & histology* / Q000254:growth & development
keywords: development; male reproductive organs; microminipig; minipig; sexual maturation; spontaneous changes; testes