Danshensu enhances autophagy and reduces inflammation by downregulating TNF-α to inhibit the NF-κB signaling pathway in ischemic flaps.

Abstract

Background: The significant distal necrosis of the random-pattern skin flaps greatly restricts their clinical applications in flap transplantation. Previous studies have demonstrated the potential of danshensu (DSS) to alleviate ischemic tissue injury. However, no research to date has confirmed whether DSS can improve the survival of ischemic flaps. This study employed DSS to examine its role and the mechanisms underlying its impact on flap survival.

Methods: RNA sequencing was conducted to identify potential targets of DSS in ischemic flaps. The viability of random-pattern skin flaps was assessed by analyzing the survival area, tissue edema, laser Doppler blood flow, and histological examination. Western blot and immunofluorescence were used to determine the protein levels related to angiogenesis, pyroptosis, macrophage polarization, autophagy, and the TNF-α-mediated NF-κB signaling pathway.

Results: Through RNA sequencing analysis, we observed differences in gene expression related to inflammation and cell death before and after flap injury. Based on the above, DSS, which possesses anti-inflammatory and antioxidant properties, came into our view and was confirmed to enhance the viability of ischemic flaps. The results showed that DSS promoted angiogenesis, induced macrophage polarization toward the M2 type, and reduced pyroptosis. We also demonstrated that enhancing autophagic flux promoted angiogenesis and reduced inflammation. In addition, DSS enhanced autophagy by suppressing the NF-κB signaling pathway through the downregulation of TNF-α. Overexpression of TNF-α activated the NF-κB signaling pathway, reduced autophagic flux, and eliminated the protective effect of DSS.

Conclusion: DSS promoted autophagy and reduced inflammation by downregulating TNF-α to suppress the NF-κB signaling pathway, thereby improving the vitality of ischemic flaps and providing strong support for its clinical application.