Schwann cells, nerve regeneration promoters in peripheral nerve tissue engineering, can be used to repair both the peripheral and central nervous systems. However, isolation and puriifcation of Schwann cells are complicated by contamination with ifbroblasts. Current reported measures are mainly limited by either high cost or complicated procedures with low cell yields or purity. In this study, we collected dorsal root ganglia from neonatal rats from which we obtained highly puriifed Schwann cells using serum-free melanocyte culture medium. The purity of Schwann cells (> 95%) using our method was higher than that using standard medium containing fetal bovine serum. The obtained Schwann cells were implanted into poly(lactic-co-glycolic acid)/chi-tosan conduits to repair 10-mm sciatic nerve defects in rats. Results showed that axonal diameter and area were signiifcantly increased and motor functions were obviously improved in the rat sciatic nerve tissue. Experimental ifndings suggest that serum-free melanocyte culture medium is conducive to purify Schwann cells and poly(lactic-co-glycolic acid)/chitosan nerve conduits combined with Schwann cells contribute to restore sciatic nerve defects.

转化生长因子-β1对瘢痕疙瘩成纤维细胞 SMAD3,7表达的影响

AIM: To study the expression of SMAD3 and SMAD7 of transforming growth factor-β 1 ( TGF-β 1) on keloid- derived fibroblasts. METHODS: The expression of SMAD3 (at 1,2,4,24,48 h)and SMAD7(at 0.5 1,1.5, 2,4,24 h) were detected by using methods of Western blot after 500 pmol/L TGF-β 1 were added to the monolayer culture system.RESULTS: The level of SMAD3 were down regulated at 24 h and the SMAD7 were maximum up regulated at 4 h when TGF-β 1 were used.CONCLUSION: TGF-β 1 may down regulate the expression of SMAD3,but up regulate that of SMAD7 .

脉冲掺钕钇铝石榴石激光对增生性瘢痕成纤维细胞胶原合成的影响

Objective In order to explore the selectively inhibitory effects of pulsed Nd:YAG laser irradiation on collagen production of scar fibroblasts in vitro.Methods Cultured fibroblasts derived from hypertrophic scars(HS) and normal human skin were irradiated with a pulsed Nd:YAG laser(wavelength 1 064 nm,pulse width 150 μ s) at various energy density levels (500,1 000,1 500 and 2 000 J/cm2).At 24 hours after laser irradiation, collagen production of fibroblasts was measured by the incorporation of 3H proline. The expression of proα 1(I)procollagen mRNA was investigated by blot hybridization techniques. Results Collagen production of HS fibroblasts was significantly increased, as 2 times as that of normal skin fibroblasts. Type I procollagen mRNA level in HS fibroblasts was markedly elevated, as 3 times as that in normal skin fibroblasts.Conclusion Pulsed Nd:YAG laser at energy density of 1 000 J/cm2 can selectively suppress collagen synthesis and type I procollagen mRNA level of HS fibroblasts.

Objective: To test the hypothesis that acute phase reactants, such as alpha 1-antitrypsin and alpha 1-acid glycoprotein, could protect mammalian cells from further damage.Methods: Human dermal fibroblasts (5 × 104) were cultured with DMEM plus 10％ FBS at 37℃ in a 5％ CO2incubator. Different doses of LPS (lipopolysaccharide) and/or acute phase reactants were added. After 24 hours, the cultured supernatant was aspirated, the cells were washed, fixed and stained by methylene blue. The unbound stain was washed off. The stained cells were solubilized in 0.1 mi of 1％ Triton X-100. The absorbance of each well was measured using an ELISA spectrophotometer. The concentration of LPS which decreased the absorbance to 70％ of the control LPS-free ) cultures was defined as LD30.Results: In order to achieve LD30 in the presence of acute phase proteins, it was necessary to alter the LPS concentrations. The LD30 of LPS treated with 0, 0.5, 2, 10mg/ml antitrypsin and 0, 0.5, 2, 10 mg/ml glycoprotein was 5.4, 6.5, 7.6, 14.2 mg/ml and 5.2, 5.9, 6.9, 10.5mg/ml, respectively. Statistically, with the treatment of more than 2 mg/ml antitrypsin or glycoprotein, LD30increased significantly.Conclusions: Our data show that fibroblasts are susceptible to the direct toxicity of LPS. Alpha 1-antitrypsin and alpha 1-acid glycoprotein can reduce the toxicity and/or increase the tolerance of mammalian cells to LPS.