Pre and Postnatal Development of the Rabbit Thin Skin

摘要

Rabbits are a popular model in laboratory animal medicine especially in the fields of humandermatology, experimental pharmacology and experimental toxicology. The present study aimed to investigateand re-evaluate, by light and scanning electron microscopy, the pre and postnatal development of rabbit skin.Early at embryonicage 15days(E15), the developing skin formed only of a single or double-layered epidermisand a loosely arranged mesodermal cells; the future dermis. At E17, epidermal stratification became clear andformed of basal layer, intermediate layer and the superficial (peridermal) layer. Additionally, the outermesodermal cells of the dermis became condensed below the basal cells of the epidermis and followed by theformation of hair placodes at embryonic period E19. At E 25 the stratification of developing epidermis becamemore distinct with an increase in the extension and differentiation of hair follicle. At late pregnancy at E28, theepidermis became fully differentiated and nearly showed mature structure where the intermediate layer ofepidermis differentiated into spinous and granular layers and the appearance of the keratinized layer. Just beforebirth atE30, the hair shaft started to protrude through skin surface associated with the development of thesebaceous glands as an outgrowth from the hair follicle. Postnatally and at one week old rabbit, the skinappeared nearly mature, the dermis became thicker with well-developed dermal papillae and the majority of thefree ends of hair shafts elongated and protruded upon the surface of epidermis. At two months old,the rabbitskin became fully matured with marked increase collagenous fibers within dermis. During pre- and postnataldevelopment of rabbit skin we could not observe any sweat glands of the examined skin samples. We canconclude that the development of the rabbit thin skin and its appendages was mainly established during theprenatal period with few developmental events during postnatal period. The extensive fur covering and absenceof the sweat gland of rabbits might be considered during intensive rabbit production to avoid stress uponrabbit thermoregulation mechanisms.