Abstract:

Objective To discuss the effect of usnic acid on the proliferation， apoptosis， migration， and invasion of the hypertrophic scar fibroblasts （HSFBs）， and to clarify its regulatory effect on the c-Jun N-terminal kinase （JNK）/mitogen-activated protein kinase （MAPK） signaling pathway. Methods The HSFBs at logarithmic growth phase were divided into control group， 10 μmol·L^－1 usnic acid group， 20 μmol·L^－1 usnic acid group， and 50 μmol·L^－1 usnic acid group. Except for control group， the cells in the other groups were treated with the corresponding concentrations of usnic acid. The survival rates of the cells in various groups were detected by methylthiazolyidiphenyl-tetrazolium bromide（MTT） method； the apoptotic rates of the cells in various groups were detected by flow cytometry；the invasion and migration abilities of the cells in various groups were detected by Transwell chamber experiment；the expression levels of phosphorylated JNK （p-JNK）， JNK， B-cell lymphoma-2（Bcl-2）， and Bcl-2-associated X protein （Bax） proteins in the cells in various groups were detected by Western blotting method. Results The MTT and flow cytometry results showed that compared with control group， the survival rates of the cells in 10， 20， and 50 μmol·L^－1 usnic acid groups were decreased （P<0.05）， and the apoptotic rates were increased （P<0.05）. Compared with 50 μmol·L^－1 usnic acid group， the survival rates of the cells in 10 and 20 μmol·L^－1 usnic acid groups were decreased （P<0.05）， and the apoptotic rates were increased （P<0.05）.The Transwell chamber experiment results showed that compared with control group，the numbers of invasion and migration cells in 10，20 and 50 μmol·L^－1 usnic acid groups were decreased（P<0.05）； compared with 10 μmol·L^－1 usnic acid group，the numbers of invasion and migration cells in 20 and 50 μmol·L^－1 usnic acid groups were decreased（P<0.05）；compared with 20 μmol·L^－1 usnic acid group，the numbers of invasion and migration cells in 50 μmol·L^－1 usnic acid groups were decreased（P<0.05）.The Western blotting results showed that compared with control group，the expression levels of Bcl-2 protein in the cells in 10， 20， and 50 μmol·L^－1 usnic acid groups were decreased（P<0.05）， and the expression levels of Bax and p-JNK proteins were increased（P<0.05）；compared with 10 μmol·L^－1 usnic acid group，the expression levels of Bcl-2 protein in the cells in 20 and 50 μmol·L^－1 usnic acid groups were decreased， and the expression levels of Bax and p-JNK proteins in the cells were increased（P<0.05）； compared with 20 μmol·L^－1 usnic acid group，the expression level of Bcl-2 protein in the cells in 50 μmol·L^－1 usnic acid group was decreased（P<0.05）， and the expression levels of Bax and p-JNK proteins were increased（P<0.05）. Conclusion Usnic acid can inhibit the proliferation， invasion， and migration of the HSFBs， induce the apoptosis of the HSFBs， and activate the JNK/MAPK signaling pathway.

Key words: Hypertrophic scar fibroblasts, Usnic acid, c-Jun amino terminal kinase, Mitogen-activated protein kinase, Cell proliferation, Apoptosis