Loureirin B Inhibits Hypertrophic Scar Formation via Inhibition of the TGF-β1-ERK/JNK Pathway

Background/Aims: Our previous study confirmed that Loureirin B (LB) can inhibit hypertrophic scar formation. However, the mechanism of LB-mediated inhibition of scar formation is still unknown. Methods: Immunohistochemistry was used to detect expression of Col1, FN and TGF-β1 in skin and scar tissue. Fibroblasts were stimulated with TGF-β1 to mimic scar formation. LB or MAPK inhibitors were used to study the pathways involved in the process. Western blotting was used to evaluate the expression of p-JNK, p-ERK, p-p38, Col1 and FN. The contractile capacity of fibroblasts was evaluated using a gel contraction assay. Tissues were cultured ex vivo with LB to further investigate the participation of ERK and JNK in the LB-mediated inhibition of scar formation. Results: FN and Col1 were up regulated in hypertrophic scars. LB down regulated p-ERK and p-JNK in TGF-β1-stimulated fibroblasts, while levels of phosphorylated p38 did not change. The down regulation of p-ERK and p-JNK was associated with a reduction of Col1 and FN. Similarly, inhibition of ERK and JNK down regulated the expression of Col1 and FN in TGF-β1-stimulated fibroblasts. LB down regulated protein levels of p-ERK and p-JNK in cultured hypertrophic scar tissue ex vivo. Conclusions: This study suggests that LB can inhibit scar formation through the ERK/JNK pathway.