Search

Objective: To study the variations of lipid peroxidation products and copper, zinc-superoxide dismutase (CuZn-SOD) in pathological scars (hypertrophic scars and keloids)., Methods: The specimens were gained from patients of voluntary contributions from May 2005 to August 2005. The tissues of hypertrophic scar (10 cases, aged 16-35 years, the mean course of disease was 2.2 years), keloid (10 cases, aged 17-32 years, the mean course of disease was 8 months) and normal skin (8 cases, aged 16-34 years) were obtained. The content of malonaldehyde (MDA)and CuZn-SOD activity were detected by spectrophotometric method. The expression of CuZn-SOD was evaluated by immunohistochemistry technique., Results: The contents of MDA and CuZn-SOD activity were significantly higher in hypertrophic scars [MDA (1.1390 +/- 0.1067) nmoL/mg prot, CuZn-SOD (31.65 +/- 2.21)U/mg prot, (P < 0.05)] and keloids [MDA (1.1900 +/- 0.074 8) nmoL/mg prot, CuZn-SOD (34.36 +/- 5.01) U/mg prot (P < 0.05)] than those of normal skin tissues [MDA (0.8213 +/- 0.0864) nmoL/mg prot, CuZn-SOD (20.60 +/- 5.56) U/mg prot]. Immunohistochemical studies indicated that the brown particles were CuZn-SOD positive signals, which mainly located cytoplasm in normal skin tissues, hypertrophic scars as well as keloids epidermal keratinocytes and dermal fibroblasts. CuZn-SOD expression evaluation in hypertrophic scars (4.14 +/- 0.90, P < 0.05) and keloids epidermal keratinocytes (4.43 +/- 0.79, P < 0.05) markedly increased when compared with normal skin tissues (2.20 +/- 0.45). The expression of CuZn-SOD in hypertrophic scars (4.00 +/- 0.82, P < 0.05) and keloids dermal fibroblasts (4.43 +/- 0.53, P < 0.05) were significantly higher than that of normal skin tissues (1.60 +/- 0.89). There were no differences in the content of MDA, CuZn-SOD activity and expression evaluation between hypertrophic scars and keloids (P > 0.05)., Conclusion: In pathological scars, the contents of MDA and CuZn-SOD activity increase and the expressions of CuZn-SOD are enlarged.

Objective: To compare the properties of collagen membranes before and after crosslinked and to establish the foundation of application of collagen membranes., Methods: Fresh bovine tendons were separated and collagen was extracted by washing, smashing and acetic acid dissolving. The collagen protein was determined by ultraviolet spectrophotometer and its characteristics were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), wavelength scanning and amino acids detecting. Collagen membranes were produced by lyophilization. And then the biocharacteristics of the membranes before and after glutaraldehyde crosslinked were compared. BMSCs separated from volunteer's bone marrow were seeded on collagen membranes before and after crosslinked by 2 x 10(3) in 100 microL medium, seven days after culture, the absorption spectrum of BMSCs was examined, and BMSCs were observed by scanning electron microscope (SEM)., Results: The contents of collagen protein were 2 mg/mL. The maximum absorption wave length appeared at about 230 nm. SDS-PAGE suggested that molecular weight of main bands was more than 66.2 x 10(3), the same as collagen marker from calf skin. There were 21.47% glycine, 12.04% praline and 10.18% hydroxyproline. No tryptophan was found. Before crosslinked, collagen membranes were in shape of white sponges and with big holes and the range of pH value was from 4.5 to 5.0. SEM showed reticular conformation and pore structure of collagen membranes, but the bore diameter was bigger. Their water-absorbing capacity was 61 times as much as their weight. The mechanical strength was 210 g/cm3. The dissolution time of collagenase was 90 minutes. After crossl inked, collagen membranes became thin, colorless, semi-transparent and compact with better tenacity. Under SEM, compact collagen fiber appeared reticular. There was lower water-absorbing capacity and pH value ranged from 6.5 to 7.0. The mechanical strength was 3,400 g/cm3 and the dissolution time of collagenase became longer. BMSCs could grow better either on before-crosslinked collagen membranes or on after-crosslinked ones., Conclusion: As biomaterial scaffolds, after crosslinked collagen membranes were better than before-crosslinked ones.

Objective: To investigate an important role of the stem cells in reconstructing the tissues and organs., Methods: Based on our own researches and combined with the review of the literature at home and abroad, the latest development of the cell therapy with the stem cells and the application of the seed cells in the tissue engineering were analyzed., Results: As the stem cells are the origin of the human tissues and organs and have a higher self-renewal ability and extensive characteristics of proliferation in vitro, their imbedding and multi-differential potentialities were illustrated. Both the embryonic stem cells and the adult stem cells had a wide prospect as ideal seed cells for reparation and reconstruction of the impaired human tissues and organs., Conclusion: The stem cells can play an important role in repairing and reconstructing the injured tissues and organs and they have a promising prospect in clinical application. The further research and wide application of the stems cells will significantly improve the therapeutic effects on the injured tissues and organs.