Skin Sensitization Test
Guinea pigs (both sexes, 6-7 weeks, 330-410 g) were purchased from Pizhou Orient Breeding (Jiangsu, China) and randomly assigned into three groups (n=10). The back hair was removed before the skin sensitization test. The Control group was treated with a blank solvent, and the allicin-treated group received topical allicin treatment (4 mg/g, measured with alliin). In the positive control group, 1-chloro-2, 4-dinitrobenzene (WT6CA-VO, Tokyo Chemical Industry) was used as a contact-sensitizing agent; a 1% sensitization concentration solution or 0.1% excitation concentration was prepared with ethanol. On sensitization day, guinea pigs were treated on the left skin, and on the excitation day were treated on the right skin. The first sensitization and administration day was defined as the first day of the test (D1). Guinea pigs were sensitized on Days 1, 8 and 15), and all groups were stimulated 14 days after the last sensitization (D29). The allergic reactions of the skin were observed at 6 h, 24 h, 48 h, and 72 h. Skin anaphylaxis includes erythema and edema. The evaluation criteria of erythema: without erythema (0), barely visible erythema (1), visible erythema (2), severe erythema (3), purplish-red erythema with mild eschar (4); The evaluation criteria of edema: without edema (0), barely visible edema (1), obviously higher than the edge of the surrounding skin (2), skin bulge 1mm or clear contour (3), skin bulge more than 1mm or blisters or ulceration (4).