ABSTRACT
BACKGROUND:The process of oxidative stress that impacts the curative effect exists in the region which accepts cel transplantation. However, there are few reports about the effects of oxidative stress on human dental pulp stem cels and relevant mechanism. OBJECTIVE:To understand the effect of hydrogen peroxide on the senescence of human dental pulp stem cels. METHODS:Human dental pulp stem cels were isolated and cultured in PBS, 100 and 200 μmol/L hydrogen peroxide for 2 hours, respectively. Cel morphology was observed under inverted microscope, degree of cel senescence monitored by β-galactosidase staining, cel proliferation ability detected by BrdU kit and cel counting method, cytoskeleton of dental pulp stem cels and expression of sirt1 tested using immunofluorescence method, and expression of sirt1 and p16 proteins measured by western blot assay. RESULTS AND CONCLUSION:Dental pulp stem cels exhibited a fibroblast-like morphology with spindle-shaped appearance. After stimulated by hydrogen peroxide, the cel volume was enlarged, theβ-galactosidase staining deepened and the proliferation of dental pulp stem cels reduced. The enhancement of senescence of dental pulp stem cels was accompanied with the increasing concentration of hydrogen peroxide, and in this process, the expression of p16 was raised while the expression of sirt1 was decreased. In conclusion, the senescence of human dental pulp stem cels can be promoted by the stimulation of hydrogen peroxide, and sirt1 and p16 are involved in this process. Our findings may provide a theoretical and experimental foundation for autologous transplantation of dental pulp stem cels.
ABSTRACT
BACKGROUND:Bone marrow mesenchymal stem cel s have attracted widespread attention for the capabilities of self-renewal and muti-differentiation, which have been used in treatment of various diseases. OBJECTIVE:To study the effect of three-dimensional spheroid culture system on the stemness and senescence of bone marrow mesenchymal stem cel s. METHODS:Mesechyaml stem cel s were isolated from the bone marrow of C57/B6 mice, 3 weeks old, and cultured onto the culture plates coated with or without chitosan. After 5 days of culture, the cel phenotype and expression of stemness related markers CD44 and Sca-1 were analyzed by flow cytometry. PI and Annexin-V staining were used to detect cel apoptosis. Also,β-Gal staining was applied for identification of aging. RESULTS AND CONCLUSION:The mouse mesenchymal stem cel s began to form spheroids on day 3. The stemness-related markers, including CD44 and Sca-1, expressed higher in spheroid mesenchymal stem cel s than the cel s under normal culturing. Compared with the normal culture group, the apoptosis and senescence of cel s from spheroid culture were lower. The results indicate that the formation of spheroids on chitosan films can increase the stemness, decrease the apoptosis and slow the senescence of mesenchymal stem cel s.