Batryticatus bombyx Improved Atopic Dermatitis in NC/Nga Mice and Impact on Inflammation and Recovery of Skin Barrier via STAT1/P38/NF-κB Downregulation and HO-1/Nrf2 Activation in HaCaT Keratinocytes.

Abstract

Introduction: Batryticatus bombyx (BB) (Beauveria bassiana Vuill.) is used as a herbal medicine and food additive. Although BB has neuroprotective and antiapoptotic effects, its impacts on atopic dermatitis (AD) are unknown. We evaluated the effects of BB in an NC/Nga mouse model of house dust mite (HDM)-induced AD, in TNF-α- and IFN-γ (TI)-stimulated HaCaT keratinocytes, and in a 3D human skin model.

Methods: NC/Nga mice were induced with HDM and treated with BB for 6 weeks. We assessed skin symptoms, serum levels of IgE, histamine, and IL-6, immune cell counts and performed histological analysis of dorsal skin tissue. Additionally, we induced inflammation in HaCaT cells and a 3D human skin model using TNF-α/IFN-γ. We measured inflammatory cytokine levels and skin hydration factors and delved into underlying mechanisms via ELISA, real-time PCR, and Western blot.

Results: BB improved skin lesions, reduced thickness, and inflammatory cell infiltration in HDM-induced mice. It alleviated scratching, improved moisture retention, and reduced IgE, histamine, and IL-6 levels. In HaCaT cells, BB inhibited thymic stromal lymphopoietin and increased hyaluronan content. It also upregulated aquaporin-3, hyaluronan synthase-1/3, filaggrin, involucrin, and occludin, enhancing skin hydration and tight junction stability. BB decreased STAT1, p38 MAPK, and NF-κB p65 levels in HaCaT cells and exhibited antioxidant effects by increasing HO-1/Nrf2 expression.

Conclusion: BB may serve as a therapeutic alternative for AD treatment by inhibiting skin inflammation.