Conclusion
These results suggested that TA could accelerate wound healing through modulation of inflammatory cytokines and growth factors and activate Erk 1/2 pathway. In conclusion, TA may be a potential agent in promoting wound healing.
Objective
This study was aimed to evaluate the effect of tannic acid (TA), a natural plant polyphenol astringent, on wound healing in vitro and in vivo, and to elucidate the underlying molecular signaling pathway in the wound healing. Approach: Cutaneous skin wounds were created in rats and then treated until closure with purified TA, serum or tissue samples were collected to test the concentration of factors by enzyme-linked immunosorbent assay (ELISA), and the expression in gene or protein was measured by quantitative real-time polymerase chain reaction or Western blot. We explored the cell-/dose-specific responses of TA (0.1-0.4 μg/mL) on proliferation and gene and protein expression of fibroblast NIH 3T3 cells.
Results
The wounds on rats treated by TA got healed faster than those in the untreated group. The histopathology study showed that TA accelerated re-epithelialization and increase in hair follicles could be detected. The levels of growth factors including basic fibroblast growth factor (bFGF), transforming growth factor-beta, and vascular endothelial growth factor in TA-treated groups were all increased, and the content of interleukin-1 (IL-1) and IL-6 was decreased significantly when compared with that of the untreated group. The NIH 3T3 cells grow faster in 6 h at concentration of 0.1 μg/mL, and the expression of bFGF in gene and protein was increased significantly in the 0.1 μg/mL TA group. Further study revealed that the protein levels of bFGF, extracellular signal regulated kinase (Erk) 1/2, and P-Erk 1/2 in Erk 1/2 pathway were increased after TA treatment. Innovation: The role of TA in wound healing efficacy is unclear; this study, therefore, assesses the effects of TA on wound healing in different periods and the underlying molecular mechanisms.