Effects of Canine-Derived Bifidobacterium animalis subsp. lactis DS008 Culture Supernatants on In Vitro Canine Keratinocytes

Microorganisms residing on the skin play a crucial role in maintaining both the integrity of the skin barrier and immune function. This study examined the effects of culture supernatants from canine-derived <i>Bifidobacterium animalis</i> subsp. <i>lactis</i> DS008 on canine keratinocytes in vitro. To induce cytokine production, canine progenitor epidermal keratinocytes (CPEK) were indirectly co-cultured with <i>Malassezia pachydermatis</i> using an insert well system to prevent direct cell-to-yeast contact, and CPEK were supplemented with 0.1%, 1%, and 10% of DS008 supernatants. mRNA expression levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-13, thymic stromal lymphopoietin (TSLP), IL-31, and keratin 10 were analyzed by real-time PCR. The protein concentrations of TSLP and IL-31 were measured by ELISA. Additionally, DS008 supernatants were applied to reconstructed canine epidermis (RCE) models exposed to lipopolysaccharide to evaluate changes in epidermal architecture. Treatment with DS008 supernatants showed significant reductions in mRNA expression of TNF-α, IL-13, TSLP, and IL-31, as well as decreased protein levels of TSLP and IL-31. Furthermore, keratin 10 mRNA expression was significantly increased, and RCE analysis demonstrated that DS008 supernatants ameliorated stratum corneum deformation. These findings suggest that postbiotics derived from canine-derived <i>Bifidobacterium animalis</i> subsp. <i>lactis</i> DS008 is a potential candidate with anti-inflammatory properties.