Effect of TNF-α and IL-6 on Compact Bone-Derived Cells

Background@#Although bone tissue engineering has already been applied clinically, its regeneration efficacy is not always sufficient. Local inflammatory cytokines are considered as the major factors that induce apoptosis of transplanted cells, thus leading to insufficient new bone formation. In this study, we focused on the effects of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) on differentiation and apoptosis of compact bone-derived cells (CBDCs). @*Methods@#CBDCs were obtained from mouse legs and cultured. The effects of TNF-α and/or IL-6 on the osteogenic differentiation and apoptosis of CBDCs were analyzed in vitro. To confirm the expression of local inflammatory cytokines in vivo, CBDCs were transplanted to the back of immunocompetent mice. @*Results@#IL-6 exerted inconsistent effects on the expression of the different osteogenic markers tested, while significantly upregulating Fas. By contrast, the addition of TNF-α dramatically reduced the expression of all tested osteogenic markers and increased Fas expression. The highest dose of IL-6 could partially reverse the repressive effect of TNF-α, while the addition of IL-6 further increased Fas expression in CBDCs compared to TNF-α alone. The results from in vivo experiments showed the presence of transplants with and without new bone formation. The transplants without bone formation were characterized by higher IL-6 and lower IL-10 expression than those with bone formation, while the expression of TNF-α did not show notable difference. @*Conclusion@#The results of this study suggest an important role for IL-6 in modulating the efficacy of bone tissue engineering, which can affect osteogenic cells both positively and negatively.

Effect of TNF-α and IL-6 on Compact Bone-Derived Cells

Background@#Although bone tissue engineering has already been applied clinically, its regeneration efficacy is not always sufficient. Local inflammatory cytokines are considered as the major factors that induce apoptosis of transplanted cells, thus leading to insufficient new bone formation. In this study, we focused on the effects of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) on differentiation and apoptosis of compact bone-derived cells (CBDCs). @*Methods@#CBDCs were obtained from mouse legs and cultured. The effects of TNF-α and/or IL-6 on the osteogenic differentiation and apoptosis of CBDCs were analyzed in vitro. To confirm the expression of local inflammatory cytokines in vivo, CBDCs were transplanted to the back of immunocompetent mice. @*Results@#IL-6 exerted inconsistent effects on the expression of the different osteogenic markers tested, while significantly upregulating Fas. By contrast, the addition of TNF-α dramatically reduced the expression of all tested osteogenic markers and increased Fas expression. The highest dose of IL-6 could partially reverse the repressive effect of TNF-α, while the addition of IL-6 further increased Fas expression in CBDCs compared to TNF-α alone. The results from in vivo experiments showed the presence of transplants with and without new bone formation. The transplants without bone formation were characterized by higher IL-6 and lower IL-10 expression than those with bone formation, while the expression of TNF-α did not show notable difference. @*Conclusion@#The results of this study suggest an important role for IL-6 in modulating the efficacy of bone tissue engineering, which can affect osteogenic cells both positively and negatively.

Nanochitosan antimicrobial activity against Streptococcus mutans and Candida albicans dual-species biofilms.

OBJECTIVE: Chitosan nanoparticle (nanochitosan) has a broad antimicrobial spectrum against diverse pathogenic microorganisms. However, its effect on dental caries-associated microorganisms, such as Streptococcus mutans and Candida albicans is yet to be explored. These microorganisms are known for causing early childhood caries. Therefore, this study was aimed at investigating nanochitosan inhibition capacity against dual-species biofilms of S. mutans and C. albicans. In this study, nanochitosan antimicrobial activity is reported against mono and dual biofilm species of S. mutans and/or C. albicans at 3 and 18 h incubation time. Nanochitosan inhibition capacity was observed through biofilm mass quantity and cell viability. RESULTS: The present study successfully synthesized nanochitosan with average diameter of approximately 20-30 nm, and also established dual-species biofilms of S. mutans and C. albicans in vitro. With nanochitosan treatment, the cell viability of both microorganisms significantly decreased with the increasing concentration of nanochitosan. There was no significant decrease in biofilm mass both in the dual and single-species biofilms after 3 h of incubation. However, greater inhibition of biofilm was observed at 18 h incubation.

Refractory Factors in Head and Neck Cancer: ATP Binding Cassette Transporters Expressed in Head and Neck Cancer Cell Lines / Oral Science International

The aim of the present study was to clarify whether ATP binding cassette transporters are refractory factors in head and neck cancer chemotherapy. For <i>in vitro</i> and <i>in vivo</i> chemotherapeutic studies, we employed a human salivary gland adenocarcinoma cell line (HSY) and a human oral squamous cell carcinoma cell line (SCCSK) with vincristine (VCR) at clinically equivalent doses. Western blot analysis, reverse transcription-polymerase chain reaction, <i>in vivo</i> evaluation in xenograft models inoculated with cultured carcinoma cell line and drug efflux analysis were performed. VCR-treated SCCSK and HSY cells, as well as xenografted SCCSK and HSY cells in tumor-bearing nude mice, were found to express MDR1/ABCB1 and MRP1/ ABCC1. In addition to MDR1 and MRP1 mRNA, HSY/VCR and its cloned cells expressed MRP7/ABCC10 mRNA, but SCCSK/VCR did not express MRP7. Furthermore, drug resistance to VCR and docetaxel decreased in HSY/VCR in the presence of a competitive MRP7 inhibitor, 17-beta-estradiol-(17-beta-D-glucuronide). These results indicate that MDR1 and MRP1 expression are refractory factors in head and neck cancer chemotherapy and suggest that induction of MRP7 expression is involved in drug resistance in salivary gland adenocarcinomas.