[Influence of lipopolysaccharide on the biological characteristics of skin fibroblasts and its potential role in wound healing].

OBJECTIVE: To investigate the influence of lipopolysaccharide (LPS) on the proliferation and collagen synthesis of normal human skin fibroblasts so as to elucidate its relation with skin wound healing. METHODS: Fibroblasts were isolated and cultured in vitro, and then exposed to different doses of LPS(0.005, 0.010, 0.050, 0.100, 0.500, and 1.000 microg/ml) from E. coli055:B5 respectively. Then the absorbance (A) value of fibroblasts was determined with the colorirneteric thiazolyl blue (MTT) assay, and the cell number was counted under inverted phase contrast microscope from the 1st day to the 9th day after LPS administration, and collagen synthesis of fibroblasts in culture medium was measured with the method of pepsin digestion after incorporation of 3H-proline into stable, single-layered, confluent fibroblasts at 7 days after LPS administration. RESULTS: Compared with control group, A value increased with the increasing concentration of LPS (0.005 microg/ml-0.500 microg/ml) and LPS of 0.100 microg/ml group had the strongest effect. The difference was remarkable from the 5th day to the 9th day(P<0.05). A value decreased when challenged with the LPS of 1.000 microg/ml and the difference was remarkable from the 3rd day to the 9th day(P<0.05). Cell number increased with the administration of LPS of different concentrations (0.005 microg/ml-0.500 microg/ml) and LPS of 0.100 microg/ml group had the strongest effect. The difference was remarkable from the 1st day to the 6th day(P<0.05). Cell number decreased remarkably when challenged with LPS of 1.000 microg/ml and the difference was remarkable from the 2nd day to the 9th day (P < 0.05). Collagen synthesis increased when challenged with LPS of different concentrations (0.005 microg/ml-0.500 microg/ml) and the 0.100 microg/ml group had the strongest effect. However, when the dose of LPS reached 1.000 microg/ml, it inhibited collagen synthesis. CONCLUSION: LPS could promote the proliferation and collagen synthesis of fibroblasts within a certain range of low doses, but over-high dose of LPS might inhibit the proliferation and collagen synthesis of fibroblasts, suggesting that LPS of certain concentrations might contribute to wound healing, while excessive LPS has negative effect on wound healing.