ObjectiveTo review the research progress of different ways of stem cells generation and cells dedifferentiation induced by reversine. MethodsThe papers related to reversine inducing cells dedifferentiation and stem cells generation were reviewed. ResultsTo obtain stem cells, there are always some disadvantages via somatic cell nuclear transfer or gene transfection. However reversine, a small molecule, can induce cells dedifferentiation which has unique advantage. But its mechanism is still unclear. ConclusionThe chemical approach for generation of induced pluripotent stem cells by reversine may take the place of other methods.
Objective Collagen type II is a characteristic molecular of chondrocyte. With continuous subculture of chondrocytes, they progressively lose the abil ity to express collagen type II. To observe the effect of collagen type IIon redifferentiation of dedifferentiated rabbit chondrocytes so as to lay a experimental foundation for use of chondrocytes in cartilage tissue engineering. Methods Cartilage was harvested under sterile conditions from tibio-femoral joints of 7-monthold New Zealand white rabbit. The rabbit articular chondrocytes were subcultured in vitro to the 7th generation (named P1-P7).Dedifferentiated rabbit chondrocytes were chosen by RT-PCR, real-time PCR, and 1, 9-dimethylmethylene blue (DMMB) assay. Then dedifferentiated rabbit chondrocytes were treated with various concentrations (0, 0.5%, 1.0%, and 1.5%) of exogenous collagen type II. The redifferentiation of dedifferentiated chondrocytes was measured by RT-PCR and real-time PCR, and the glycosaminoglycan content was determined by DMMB assay. Results The glycosaminoglycan content of P1-P7 chondrocytes were (12.20 ± 0.17), (11.20 ± 0.24), (11.18 ± 0.16), (10.89 ± 0.50), (8.73 ± 0.19), (9.39 ± 0.32), and (8.18 ± 0.20) μg, respectively, showing no significant difference (P gt; 0.05) among P2, P3, and P4, and showing significant differences (P lt; 0.05) among other generations. The mRNA of collagen type I, collagen type II, and aggrecan expressed at P4-P7, showing no significant difference in the mRNA expression of collagen type I (P gt; 0.05) and significant differences in the mRNA expressions of collagen type II and aggrecan (P lt; 0.05) among P4-P7. The glycosaminoglycan content at concentrations of 0, 0.5%, 1.0%, and 1.5% were (8.20 ± 0.16), (14.61 ± 0.33), (13.93 ± 0.25), and (19.59 ± 0.46) μg, showing significant differences among different concentrations (P lt; 0.05). With exogenous collagen type II concentrations increased, the mRNA expressions of collagen type II and aggrecan gene were up-regulated gradually, but collagen type I gene was down-regulated, showing significant differences (P lt; 0.05). Conclusion Collagen type II can promote redifferentiation and activation of dedifferentiated rabbit chondrocytes.
Diabetes is characterised by hyperglycaemia resulted as the relative or absolute insulin deficiency which is closely related to islet beta cell failure. Apoptosis is the core mechanism of beta cell failure according to the studies on human islet. However, apoptosis can’t fully explain the loss of beta cell mass in the process of type 2 diabetes or the protective effect of early intervention. Recently, some other possible mechanisms of beta cell dysfunction have been proposed and dedifferentiation of beta cell draws extensive attention. Evidences of beta cell dedifferentiation in type 2 diabetes patients and animal models outlined and the transcription factors which determine beta cells of identity during this procedure are discussed in this review.