Genotoxic properties of materials used for endoprostheses: Experimental and human data.

Approximately 2 million endoprostheses are implanted annually and metal ions as well as particles are released into the body from the materials which are used. This review describes the results of studies concerning genotoxic damage caused by artificial joints. DNA damage leads to various adverse long-term health effects in humans including cancer. Experiments with mammalian cells showed that metal ions and particles from orthopedic materials cause DNA damage. Induction of chromosomal aberrations (CA) was found in several in vitro experiments and in studies with rodents with metals from orthopedic materials. Human studies focused mainly on induction of CA (7 studies). Only few investigations (4) concerned sister chromatid exchanges, oxidative DNA damage (2) and micronucleus formation (1). CA are a reliable biomarker for increased cancer risks in humans) and were increased in all studies in patients with artificial joints. No firm conclusion can be drawn at present if the effects in humans are due to oxidative stress and if dissolved metal ions or release particles play a role. Our findings indicate that patients with artificial joints may have increased cancer risks due to damage of the genetic material. Future studies should be performed to identify safe materials and to study the molecular mechanisms in detail.

Mycophenolate Mofetil Modulates Differentiation of Th1/Th2 and the Secretion of Cytokines in an Active Crohn's Disease Mouse Model.

Mycophenolate mofetil (MMF) is an alternative immunosuppressive agent that has been reported to be effective and well tolerated for the treatment of refractory inflammatory bowel disease (IBD). The aim of this study was to investigate the therapeutic effect of MMF on intestinal injury and tissue inflammation, which were caused by Crohn's disease (CD). Here, trinitrobenzene sulfonic acid-relapsing (TNBS) colitis was induced in mice; then, we measured the differentiation of Th1/Th2 cells in mouse splenocytes by flow cytometry and the secretion of cytokines in mice with TNBS-induced colitis by real-time polymerase chain reaction and/or enzyme-linked immunosorbent assay (RT-PCR/ELISA). The results show that MMF significantly inhibited mRNA expression of pro-inflammatory cytokines IFN-γ, TNF-α, IL-12, IL-6, and IL-1ß in mice with TNBS-induced colitis; however, MMF did not inhibit the expression of IL-10 mRNA. Additionally, ELISA showed that the serum levels of IFN-γ, TNF-α, IL-12, IL-6, and IL-1ß were down-regulated in a TNBS model of colitis. Flow cytometric analysis showed MMF markedly reduced the percentages of Th1 and Th2 splenocytes in the CD mouse model. Mycophenolic acid (MPA) also significantly decreased the percentages of splenic Th1 and Th2 cells in vitro. Furthermore, MMF treatment not only significantly ameliorated diarrhea, and loss of body weight but also abrogated the histopathologic severity and inflammatory response of inflammatory colitis, and increased the survival rate of TNBS-induced colitic mice. These results suggest that treatment with MMF may improve experimental colitis and induce inflammatory response remission of CD by down-regulation of pro-inflammatory cytokines via modulation of the differentiation of Th1/Th2 cells.

[Study on anti-aging effect of ginsenoside Rg1 in serial transplantation of hematopoietic stem cells and progenitor cells].

OBJECTIVE: To investigate the anti-aging effect of ginsenoside R1 in serial transplantation of hematopoietic stem cells and progenitor cells. METHOD: HSC/HPC aging model in vivo was established through the Sca-1 (+) HSC/HPC serial transplantation of male donor mice that had been separated and purified by the magnetic-activated cell sorting method. The female recipient mice that had been radiated with lethal dose of 60Co gamma ray were divided into four groups: the control group, the aging group, the Rg1-treated aging group and the Rg1 anti-aging group. The expression of Sry genes in bone marrow cells of recipient mice was analyzed by fluorescence quantitative PCR, in order to determine the source of hematopoietic reconstruction cells, observe the survival time and the recovery of the hematology of peripheral blood, and study the reconstruction of the hematopoietic function of recipient mice, the hematopoietic recovery promoted by Rg1, the culture of CFU-Mix of hemopoietic progenitor cells, the cell cycle analysis and aging-related SA-beta-Gal staining analysis on biological characteristics of Sca-1 (+) HSC/HPC aging, and the effect of Rg1 in vivo regulation on Sca-1 + HSC/HPC aging. RESULT: The hematopoietic reconstruction cells of female recipient mice were derived from male donor mice. With the serial transplantation, the 30-day survival rate and the hematology in peripheral blood of recipient mice decreased. Sca-1 (+) HSC/HPC showed aging characteristics: the ratio of cells in G0/G1 phase and the positive rate of SA-beta-gal staining increased, whereas the number of CFU-Mix decreased. Compared with the aging group of the same generation, Rg1 -treated aging group and Rg1 anti-aging group showed higher 30-day survival rate and WBC, HCT, PLT and CFU-Mix, and lower cell ratio in Sca-1 (+) HSC/HPC G0/G1 stage and positive rate of SA-beta-gal staining. The Rg1 anti-aging group showed more significant changes than the Rg1 -treated aging group. CONCLUSION: Ginsenoside Rg1 has the effect of delaying and treating Sca-1 (+) HSC/HPC aging during the serial transplantation. Rg1 's anti-aging effect is superior to its effect of treating aging.

[Optimization of magnetic activated cell sorting and the biological characteristics of isolated cells].

AIM: To optimize the traditional magnetic activated cell sorting (MACS) so as to enhance the purification and keep the viability of cells after separation. METHODS: Take stem cell antigen-1 labeled hemopoietic stem/progenitor cells (Sca-1(+);HSC/HPC) for example. The traditional MACS and the optimized MACS were applied to obtain the Sca-1(+); HSC/HPC from mouse bone marrow respectively. The purifications of Sca-1(+); cells from two groups were tested by flow cytometry; The survival rates of Sca-1(+); cells from two groups were detected by trypan blue dye; The proliferation of Sca-1(+); cells was detected by cell counting kit-8(CCK-8); the differentiation capacity of Sca-1(+); cells was measured by CFU-Mix. RESULTS: The purification of Sca-1(+); cells was up to 93% by the optimized MACS compared to 87% by the traditional one; the recovery rate of positive cells was 73% by the optimized MACS compared to 62.3% by the traditional one; there was no statistical difference in the viability and proliferation of Sca-1(+); cells and the capacity of producing CFU-Mix between two groups. CONCLUSION: The optimized MACS can significantly enhance the purification and recovery rate of Sca-1(+); cells without influence of cell viability and biological features, which can be considered to apply in other MACS.

Senescence as a consequence of ginsenoside rg1 response on k562 human leukemia cell line.

AIMS AND BACKGROUND: Traditional chemotherapy strategies for human leukemia commonly use drugs based on cytotoxicity to eradicate cancer cells. One predicament is that substantial damage to normal tissues is likely to occur in the course of standard treatments. Obviously, it is urgent to explore therapies that can effectively eliminate malignant cells without affecting normal cells. Our previous studies indicated that ginsenoside Rg1 (Rg1), a major active pharmacological ingredient of ginseng, could delay normal hematopoietic stem cell senescence. However, whether Rg1 can induce cancer cell senescence is still unclear. METHODS: In the current study, human leukemia K562 cells were subjected to Rg1 exposure. The optimal drug concentration and duration with K562 cells was obtained by MTT colorimetric test. Effects of Rg1 on cell cycle were analyzed using flow cytometry and by SA-ß-Gal staining. Colony-forming ability was measured by colony-assay. Telomere lengths were assessed by Southern blotting and expression of senescence-associated proteins P21, P16 and RB by Western blotting. Ultrastructural morphology changes were observed by transmission electron microscopy. RESULTS: K562 cells demonstrated a maximum proliferation inhibition rate with an Rg1 concentration of 20 µ molL-1 for 48h, the cells exhibiting dramatic morphological alterations including an enlarged and flat cellular morphology, larger mitochondria and increased number of lysosomes. Senescence associated-ß-galactosidase (SA-ß-Gal) activity was increased. K562 cells also had decreased ability for colony formation, and shortened telomere length as well as reduction of proliferating potential and arrestin G2/M phase after Rg1 interaction. The senescence associated proteins P21, P16 and RB were significantly up-regulated. CONCLUSION: Ginsenoside Rg1 can induce a state of senescence in human leukemia K562 cells, which is associated with p21-Rb and p16-Rb pathways.