Histological changes to the skin of Merino sheep following deep dermal and subcutaneous injections of sodium lauryl sulfate.

Abstract

OBJECTIVES: To characterise the changes caused to sheep skin by deep dermal and subcutaneous injections of sodium lauryl sulfate (SLS) and describe the subsequent healing process. PROCEDURE: On 6 sheep 20 small areas of skin were each given deep dermal and subcutaneous injections of 0.2 mL of 7% SLS. Biopsies were collected at intervals up to 28 days after treatment and the histological changes in each of the treated skin samples were assessed and graded. RESULTS: There was no evidence of alterations in behaviour, weight gain or appetite of the sheep following the injections. Initial swelling of the treated site subsided by day 14, leaving a firm, slightly raised crust. At day 21, the treated area was depressed and covered by a scab, which sloughed completely by day 28. There was necrosis of the subcutis and deep dermis 2 min after treatment, followed by inflammation, fibroplasia, angiogenesis and tissue remodelling. CONCLUSION: Injection of SLS caused almost immediate local necrosis followed by eschar formation, sloughing and scarring of treated skin. Deep dermal and subcutaneous SLS is potentially useful as a chemical alternative to mulesing.