Abstract:

Objective To determine the expressions of transcription factor activator protein-2α （AP-2α）, estrogen receptor-β （ER-β） and matrixmetalloproteinase-9 （MMP-9） in lichen planus （LP） lesions and their significance. Methods Tissue samples were resected from the lesions of 30 patients with LP and normal skin of 30 human controls. An immunohistochemical method using streptavidin-peroxidase （SP） was performed to detect the expression of ER-β and MMP-9, reverse transcription-PCR and Western blot to measure the mRNA and protein expressions of AP-2α, ER-β and MMP-9 in these specimens. Results There was a significant decrease in the mRNA expressions of AP-2α （0.488 ± 0.039 vs. 1.008 ± 0.023, P < 0.01 ） and ER-β （0.365 ± 0.032 vs. 0.998 ± 0.036, P < 0.01）, together with an increase in the expression of MMP-9 （1.237 ± 0.027 vs. 0.567 ± 0.015, P < 0.01） in the LP lesions compared with the control specimens; similar results were observed for the protein expressions of AP-2α, ER-β and MMP-9. In LP lesions, the expression of AP-2α was positively correlated with that of ER-β （R = 0.89, P < 0.01）, but negatively correlated with that of MMP-9 （r ＝ -0.91, P < 0.01）. Conclusions The down-regulation of ER-β expression and up-regulation of MMP-9 expression may be ascribed to the abnormal regulation of upstream target genes mediated by the decreased expression of AP-2α, which may be involved in the pathogenesis of LP.

Key words: MMP-9