Expression of matrix metalloproteinase-2,9 and its inhibitor in hypertplastic scars and its biological significance

Objective To investigate the changes of gene expression and protein contents of matrix metalloproteinase-2,9 and its inhibitor(TIMP-2) in normal skin versus hyperplastic scars and appraise their biological significance.Methods Morphological characteristics of hperplastic scar and normal skin were studied by pathological techniques.After the total RNA of hyperplastic scars at different periods after wounding and normal skin was isolated and purified to mRNA,gene expression levels and protein contents of MMP-2,9 and TIMP-2 were examined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blotting.Results In the skin,the genes of MMP-2,9 and TIMP-2 were weakly expressed,and protein contents were low.In proliferative scar,the contents of gene transcripts and proteins of these 2 MMPs and TIMP-2 significantly increased(P0.05).In mature scar,although mRNA levels of MMP-2,9 were restored to the levels of normal skin,the protein contents of these 2 MMPs were significantly higher than those of normal skin(P0.05).At the same time,the mRNA and protein contents of TIMP-2 decreased to the levels of normal skin.Conclusions Enhancement of MMP-2,9 and TIMP-2 expression might be related to formation of hyperplastic scar,while high protein levels of these 2 MMPs and low content of TIMP-2 protein might be associated with hyperplastic scar reaching the mature stage.