Résumé
ObjectiveTo observe the influence of lipopolysaccharide (LPS) on collagen metabolism of normal human skin fibroblasts and its biological role in the formation of hypertrophic scar.Methods Fibroblasts were isolated and cultured in vitro,and then exposed to different doses of LPS (0.005,0.01,0.05,0.1,0.5,1.0 μg/ml) from E.coli.055:B5 respectively.The expression of proccllagen type Ⅰ,Ⅲand collagenase mRNAs was tested by RT -PCR.Fibroblasts from hypertrophic scar tissue obtained from the same patients in the same culture passage were used as control.ResultsCompared with control group,the expression of procollagen typeⅠ,Ⅲ mRNAs in normal skin fibroblasts increased (0.323 ± 0.041,0.303 ± 0.063,0.391 ± 0.071,0.344 ± 0.086,0.488 ± 0.059,0.401 ± 0.087,0.616 ± 0.107,0.434 ±0.084,0.823 ±0.092,0.542 ± 0.082),while the expression of collagenase mRNAs of normal skin fibroblasts depressed(0.598 ± 0.068,0.556 ± 0.049,0.441 ± 0.043,0.372 ± 0.083,0.260 ± 0.027 ).When LPS was set to the concentration of 0.005 μg/ml,it showed a concentration dependent manner.However,when the concentration of LPS was set to 0.5 μg/ml,the expression of procollagen type Ⅰ,Ⅲ and collagenase mRNAs of normal skin fibroblasts began to decrease (0.451 ± 0.063,0.374 ± 0.072,0.360 ± 0.062).When the concentration of LPS was set to 1.0 μg/ml,the expression of procollagen type Ⅰ,Ⅲ mRNAs (0.162 ± 0.025,0.171 ± 0.061 )were inhibited and the expression of collagenase mRNAs began to increase (0.444 ±0.114).When the concentration of LPS was set to 0.1 μg/ml,the expression of procollagen type Ⅰ,Ⅲ and collagenase mRNAs of normal skin fibroblasts(0.823 ±0.092,0.542 ±0.082,0.260 ±0.027)was similar to that of hypertrophic scar tissue fibroblasts(0.829 ±0.049,0.569 ±0.038,0.277 ±0.059).ConclusionsThis result supported that LPS may be an important factor in collagen metabolism of normal skin fibroblasts and it plays an important role in hypertrophic scar formation.
Résumé
Objective To observe the influence of lipopolysaccharide (LPS) on the cell cycle and the mRNAs expression of procollagen type Ⅰ , Ⅲ of normal human skin fibroblasts. Methods Purified dermal fibroblasts were exposed to different doses of LPS(0. 005 ～ 1.0 μg/ml) from E. coli. Then the cell cycle of fibroblasts at logarithmic stage at day 7 after LPS administration was assayed with flow cytometry.The expression of procollagen type Ⅰ , Ⅲ and collagenase mRNAs was tested by RT-PCR. Results The percentage of S phase cells in cell cycle of normal human skin fibroblasts increased when LPS concentrations were changed from 0. 005 to 0. 1 μg/ml, and the increase showed a concentration dependent manner. However, when the concentration of LPS was 0. 5 μg/ml, the percentage of S phase cells began to decrease, but still higher than normal control. When LPS concentration reached 1.0 μg/ml, the percentage of S phase cells were lower than normal control. The expression of procollagen type Ⅰ , Ⅲ mRNAs of normal skin fibroblasts increased when LPS was challenged to the concentration of 0. 005 μg/ml, and the influence showed a concentration dependent manner. However, when the concentration of LPS was 0. 5 μg/ml, the influence of LPS on the expression of procollagen type Ⅰ , Ⅲ of normal skin fibroblasts began to decrease.When the concentration of LPS reached 1.0 μg/ml, the expression of procollagen type Ⅰ , Ⅲ mRNAs were inhibited. Conclusions LPS promoted the proliferation and collagen synthesis of normal human skin fibroblasts within a certain range of low doses, while high doses of LPS might inhibit the proliferation and collagen synthesis of normal human skin fibroblasts.