Abstract: Objective: To determine the impact of gut microbial metabolite indole-3-carboxaldehyde (IAID) on mouse model of atopic dermatitis (AD). Methods: C57 mice were divided into 3 groups: control group, model group and IAID group. Vitamin D3 analog MC903 was applied on on mice ear to establish an AD-like model. The mice in IAID group were gavaged with 65 μg/kg IAID, and the same amount of DMSO as a vehicle control through administration by gavaging. At day 10, The mice ears were observed for any inflammatory sign and the thickness of the ears were measured. The RT-PCR technique was used to detect the expression of IL4, IL5, IL6, IL13, IL33, TSLP in whole skin and ELISA technique was used to detect the level of total IgE. Results: Compared to model group, we observed a obvious alleviation in IAID group with a decreased level of total IgE (P<0.001) and IL13, TSLP (P<0.05). Conclusion: Gut microbial metabolite IAID can relieve the severity of AD-like inflammation in the mice model.

Key words: atopic dermatitis, indole-3-carboxaldehyde (IAID ), gut microbial flora