BackgroundAntioxidants have been shown to enhance the proliferation of adipose-derived mesenchymal stem cells (ADMSCs) in vitro, although the detailed mechanism(s) and potential side effects are not fully understood.In this study, human ADMSCs cultured in ImF-A medium supplemented with antioxidants (N-acetyl-l-cysteine and ascorbic acid-2-phosphate) and fibroblast growth factor 2 (FGF-2) were compared with ADMSCs cultured with FGF-2 alone (ImF) or with FGF-2 under 5% pO2 conditions (ImF-H).ResultsDuring log-phase growth, exposure to ImF-A resulted in a higher percentage of ADMSCs in the S phase of the cell cycle and a smaller percentage in G0/G1 phase. This resulted in a significantly reduced cell-doubling time and increased number of cells in the antioxidant-supplemented cultures compared with those supplemented with FGF-2 alone, an approximately 225% higher cell density after 7 days. Western blotting showed that the levels of the CDK inhibitors p21 and p27 decreased after ImF-A treatment, whereas CDK2, CDK4, and CDC2 levels clearly increased. In addition, ImF-A resulted in significant reduction in the expression of CD29, CD90, and CD105, whereas relative telomere length, osteogenesis, adipogenesis, and chondrogenesis were enhanced. The results were similar for ADMSCs treated with antioxidants and those under hypoxic conditions.ConclusionAntioxidant treatment promotes entry of ADMSCs into the S phase by suppressing cyclin-dependent kinase inhibitors and results in rapid cell proliferation similar to that observed under hypoxic conditions.

Evaluate the influence instability by AMD corrosion based on the slope of a large-scale sulfide mine. On the basis of the corrosion experiment, carry out the researches on the solution ion change rules before vs. after evaluation; set up the mathematical expression of the AMD corrosion amount through the analysis of the corrosion mass transfer; establish the acid load deposition calculation model by AMD based on the oxidation mechanism analysis of sulfide ores; the engineering application indicates that, at the puddle, wells, sump and fracturing catchment areas, AMD acid load deposition was accumulated and the acid load is significantly higher than other area which is up to 500 mg/L; on the slope surface, as the time period affected by AMD is shorter, acid load is between 166~300mg/L; for the streams far away from mines, the acid load, less than 20mg/L, is at the minimum level. The model calculation result is consistent with the spot reality.