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

## TL;DR

This study shows that postbiotics from a canine-specific Bifidobacterium strain reduce inflammation and improve skin barrier function in dogs.

## Contribution

The study demonstrates the anti-inflammatory and skin barrier-enhancing effects of a canine-derived Bifidobacterium postbiotic for the first time.

## Key findings

- DS008 supernatants reduced inflammatory cytokines like TNF-α, IL-13, TSLP, and IL-31 in canine keratinocytes.
- Treatment increased keratin 10 expression, supporting skin cell adhesion and barrier formation.
- DS008 supernatants restored stratum corneum structure in canine epidermis models.

## Abstract

This study investigated the impact of postbiotics derived from Bifidobacterium animalis subsp. Lactis DS008 on in vitro canine keratinocytes. The DS008 supernatants significantly reduced the expression of inflammatory cytokines linked to itching and skin irritation. In addition, treatment with DS008 supernatants significantly increased keratin 10 expression, which helps skin cells adhere to one another and form a protective barrier. When applied to reconstructed canine epidermis models with a disrupted stratum corneum, the DS008 supernatants induced the restoration of the stratum corneum’s structure. Altogether, these results indicate that postbiotics from canine Bifidobacterium animalis subsp. lactis DS008 may represent a promising anti-inflammatory approach and support skin barrier health in dogs.

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 Bifidobacterium animalis subsp. lactis DS008 on canine keratinocytes in vitro. To induce cytokine production, canine progenitor epidermal keratinocytes (CPEK) were indirectly co-cultured with Malassezia pachydermatis 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 Bifidobacterium animalis subsp. lactis DS008 is a potential candidate with anti-inflammatory properties.