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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.
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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.
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Objective To study the signal transduction mechanism of nicotine induced periodontal ligament fibroblasts (PDLFs) apoptosis. Methods This study used 1 μg/ml, 10μg/ml and 100μg/ml nicotine to intervene PDLFs cells for 24h separately. NF-κB, p53, I-κB and Caspase3 expression were detected. Results After Nicotine was done on PDLFs cells for 24h, the transcription of p53, and Caspase3,and the translation of Caspase 3 protein were increased, while NF-κB was decreased. At the same time, the transcription of NF-κB decreased gradually with the concentration of nicotine increased ( r = 0. 707, F =33. 705, P ＜0. 01 ), nevertheless, I-κB was reversed ( r =0. 964, F =374. 883, P ＜0. 01 ). p53 expression was increased gradually with the concentration of nicotine increased ( r =0. 957, F = 153. 377, P ＜0. 01).Both Caspase3 mRNA (r =0.935, F =318.371, P ＜0.01) and protein (r =0.677, F =8. 459, P ＜ 0. 05 )increased gradually. Conclusion Nicotine induced PDLFs apoptosis was mediated through NF-κB and p53 pathway.
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Objective To offer the histological proof of rabbits rupture repair after early mobilization.Method New zealand rabbits were random divided into 3 groups, including normal group, mobilization group (the experimental group) , and immobilization group.All rabbits' achilles tendons were inspected, and the histological difference were observed under light microscope and electron microscope respectively.Result The collagen fibers of the achilles tendons in the mobilization group under light microscope showed that it arrayed more regularly than in immobilization group.Fibroblasts were more maturate.The diameters of collagen fibrils under electron microscope in mobilization group were thicker[(8.417 ± 1.649)μm vs (6.818 ± 1.025)μm, t = 2.76, P ＜ 0.05] than immobilization group.The results showed statistical significance[(26.915 ±2.123)nm vs (21.725 ±3.768)nm, t =4.12, P ＜0.01].Conclusion Early mobilization after operation can promote the histological healing of achiles tendon.