Intradermal injection of Cutibacterium acnes and staphylococcus: A pustular acne‐like murine model.

Background: Skin 16S microbiome diversity analysis indicates that the Staphylococcus genus, especially Staphylococcus aureus (S. aureus), plays a crucial role in the inflammatory lesions of acne. However, current animal models for acne do not fully replicate human diseases, especially pustular acne, which limits the development of anti‐acne medications. Aims: The aim is to develop a mouse model for acne, establishing an animal model that more closely mimics the clinical presentation of pustular acne. This will provide a new research platform for screening anti‐acne drugs and evaluating the efficacy of clinical anti‐acne experimental treatments. Methods: Building upon the existing combination of acne‐associated Cutibacterium acnes (C. acnes) with artificial sebum, we will inject a mixture of S. aureus and C. acnes locally into the dermis in a 3:7 ratio. Results: We found that the acne animal model with mixed bacterial infection better replicates the dynamic evolution process of human pustular acne. Compared to the infection with C. acnes alone, mixed bacterial infection resulted in pustules with a distinct yellowish appearance, resembling pustular acne morphology. The lesions exhibited redness, vascular dilation, and noticeable congestion, along with evident infiltration of inflammatory cells. This induced higher levels of inflammation, as indicated by a significant increase in the secretion of inflammatory factors such as IL‐1β and TNF‐α. Conclusion: This model can reflect the clinical symptoms and development of human pustular acne, overcoming the limitations of animal models commonly used in basic research to study this situation. It provides support for foundational research and the development of new acne medications. [ABSTRACT FROM AUTHOR]