[Morphological features of the nuclei of the principal cells in the epididymal duct in mice, with special emphasis on the regional differences in the duct and age-related changes].
The mouse epididymal duct is divided into five segments (I-V). In this study, morphological features of the nuclei of the principal cells in the epididymal duct were examined in mice from 20 to 360 days of age, with special reference to the regional differences in the duct and age-related changes. By morphological characteristics of the nuclei, the principal cells were classified into three types; the cells with a nucleus of usual size, those with two nuclei, and those with a large nucleus. Binuclear principal cells were mainly distributed in segments IV and V. They appeared at 30 days of age and increased to about 20% out of the all principal cells in segment IV and about 30% in segment V with morphological differentiation of the segment until 40 days. After 40 days, they furthermore increased in segment IV, but decreased in segment V. The cells with large nuclei are frequently seen in segments IV and V after 120 days. Especially in segment V, about 70% of the principal cells had large nuclei. The nuclei with deep invaginations of the nuclear membrane or slit figures were frequently observed after 120 days of age. The principal cells with such nuclei were rare in segment I, 10-20% in segments II-IV, and about 60% in segment V. These nuclei were similar in size to the usual nuclei in segments II and III but large in segments IV and V. In conclusion, morphological characteristics of the nuclei in the principal cells are different between the proximal and distal regions which are functionally different, and the principal cells with two nuclei and those with a deformed nucleus increase in number in relation to the functional differentiation and aging of the epididymal duct.
D000367:Age Factors; D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D004822:Epididymis / Q000166:cytology* / Q000502:physiology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains