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Morphological changes in the skin and wool fibres of Merino sheep infused with mouse epidermal growth factor
Abstract:
Intravenous infusion of 4.5-4.7 mg of mouse epidermal growth factor (mEGF) into nine castrated male Merino sheep for 26 h resulted in complete casting of the fleeces 6-8 days later. The morphological changes which occurred in the skin were studied in skin samples taken before infusion and at intervals between 1 h and 42 days after the infusion had begun. Wool fibres from the shed fleeces were examined with the scanning electron microscope. Increased cell proliferation occurred in the epidermis and sebaceous glands, whereas the wool follicles regressed. Transient dermal haemorrhages occurred during the first 3 h of infusion. The fibre and inner root sheath in the keratogenous zone of 30-40% of the follicles were partially disrupted within the first 6 h of mEGF infusion; catagen began in all follicle bulbs within 24 h. Fibre and inner root sheath production, although markedly reduced, continued in about 60% of follicles which had partially regressed, but production ceased in the remainder in which tapered ends formed on the fibres prior to shedding. Follicles began to regenerate asynchronously 4-8 days after the beginning of infusion and completed their development during the next 3 weeks. The follicle regression and fleece casting induced by mEGF infusion, and subsequent follicle regeneration were completed more rapidly than observed previously with other depilatory agents, and, except for prolonged epidermal thickening, there was no lasting cutaneous abnormality.
Insights
Mouse epidermal growth factor (mEGF) infusion rapidly induced fleece shedding in sheep by causing follicle regression and regeneration. This process was faster than other depilatory agents, with no lasting skin abnormalities observed.
Area of Science:
- Dermatology
- Animal Science
- Regenerative Medicine
Background:
- Wool follicle cycling and fleece shedding are complex biological processes.
- Epidermal growth factor (EGF) plays a crucial role in cell proliferation and tissue regeneration.
- Understanding factors that influence wool follicle dynamics is important for sheep husbandry and textile industries.
Purpose of the Study:
- To investigate the effects of mouse epidermal growth factor (mEGF) infusion on wool follicles and skin morphology in sheep.
- To determine the timeline of follicle regression, fleece casting, and subsequent regeneration induced by mEGF.
- To compare the efficacy and speed of mEGF-induced fleece shedding with other known depilatory agents.
Main Methods:
- Intravenous infusion of mEGF into castrated male Merino sheep.
- Collection and morphological analysis of skin samples at various time points post-infusion.
- Examination of shed wool fibres using scanning electron microscopy.
- Histological assessment of wool follicle and epidermal changes.
Main Results:
- mEGF infusion led to complete fleece casting within 6-8 days.
- Increased epidermal and sebaceous gland proliferation occurred alongside wool follicle regression.
- Follicle catagen was initiated within 24 hours, with partial disruption observed earlier.
- Follicle regeneration commenced asynchronously between 4-8 days post-infusion.
- The entire process of regression and regeneration was completed more rapidly than with other agents.
Conclusions:
- mEGF effectively induces rapid and reversible fleece shedding in sheep.
- The study demonstrates mEGF's potent effects on wool follicle dynamics and skin regeneration.
- mEGF represents a potentially efficient agent for depilation with minimal long-term adverse effects on skin.