The Gross Morphology and Scanning Electron Microscopic Evaluation of the Skin Surface in Congenic Strains of Hairless Mice

The study examined the skin surface of three congenic strains of hairless mice using gross morphology and scanning electron microscopy. It was observed that these mice initially grew a coat of hair, which began to shed around the eyes at 12 days old, progressing to complete alopecia by 3-4 weeks, except for vibrissae. As the mice aged, their skin thickened, became loose, and developed folds, while claws elongated and vibrissae became sparse. Differences in pigmentation were noted among strains, with BALB/c mice lacking pigment, unlike DBA/2 and C57BL/6 mice. Subcutaneous nodules and cysts were observed, increasing in size and number with age, and hair follicles showed widening and keratin accumulation before hair loss.