Antimicrobial Effects of Mouse Adipose-Derived Mesenchymal Stem Cells Encapsulated in Collagen-Fibrin Hydrogel Scaffolds on Bacteroides fragilis Wound Infection in vivo.

Background: Anaerobes are the causative agents of many wound infections. B. fragilis is the most prevalent endogenous anaerobic bacterium causes a wide range of diseases, including wound infections. This study aimed to assess the antibacterial effect of mouse adipocyte derived-mesenchymal stem cell (AD-MSCs) encapsulated in collagen-fibrin (CF) hydrogel scaffolds on B. fragilis wound infection in an animal model.

Methods: Stem cells were extracted from mouse adipose tissue and confirmed by surface markers using flow cytometry analysis. The possibility of differentiation of stem cells into osteoblast and adipocyte cells was also assessed. The extracted stem cells were encapsulated in the CF scaffold. B. fragilis wound infection was induced in rats, and then following 24 h, collagen and fibrin-encapsulated mesenchymal stem cells (MSCs) were applied to dress the wound. One week later, a standard colony count test monitored the bacterial load in the infected rats.

Results: MSCs were characterized as positive for CD44, CD90, and CD105 markers and negative for CD34, which were able to differentiate into osteoblast and adipocyte cells. AD-MSCs encapsulated with collagen and fibrin scaffolds showed ameliorating effects on B. fragilis wound infection. Additionally, AD-MSCs with a collagen scaffold (54 CFU/g) indicated a greater effect on wound infection than AD-MSCs with a fibrin scaffold (97 CFU/g). The combined CF scaffold demonstrated the highest reduction in colony count (the bacteria load down to 29 CFU/g) in the wound infection.

Conclusion: Our findings reveal that the use of collagen and fibrin scaffold in combination with mouse AD-MSCs is a promising alternative treatment for B. fragilis.