ABSTRACT
When hairs are plucked and examined by transmitted white light, the nude mouse hairs have multiple fractures and tend to be twisted by numerous fusiform bulgings. The inner root sheath of nude mouse follicles and the cuticle and cortex of the shafts were missing in an irregular pattern. By scanning electron microscopy, nude mouse hairs were poorly defined and covered by projections of keratinocytes on the epidermal surface. In ovaries, the number of follicles in 10-day-old females is higher than normal; ovulation starts at 2.5 months of age (2 weeks later than normal), and nude mouse ovaries stop ovulating by 4 months of age. The nude rat (two alleles, gene symbols: rnu and nznu) resembles the nude mouse in that it is athymic and has a hair defect. The nude mouse has been used in large numbers of studies, unrelated to skin research, in which immunodeficiency is useful.
