ABSTRACT
Recent studies demonstrated that the molecules secreted from astrocytes play important roles in the cell fate determination of neural stem cells (NSCs). However, the exact molecules involved and its possible mechanisms in the process remain largely unknown. In this study, astrocyte-conditioned medium (ACM) obtained from astrocytes unstimulated or stimulated by lipopolysaccharide was prepared to treat NSCs. The results showed that both the proliferation and differentiation of NSCs treated with stimulated ACMs were significantly increased compared with those treated with unstimulated ACM. Interleukin-6 (IL-6) antibody neutralization of the ACMs decreased NSC proliferation and astrogliogenesis, while NSC neurogenesis was increased. In contrast, recombinant IL-6 cytokine increased NSC proliferation and astrogliogenesis, but decreased neurogenesis. Furthermore, the expression of phosphorylated signal transducer and activator of transcription 3 (p-stat3) protein as well as serial of basic helix-loop-helix transcription factors (bHLH) mRNA in NSCs exposed to stimulated ACMs significantly increased, respectively. The expression levels of p-stat3 protein and bHLH mRNA of NSCs were significantly altered after adding anti-IL-6 antibody or recombinant IL-6, respectively. The data suggest that IL-6 secreted from activated astrocytes participates in ACM-induced proliferation and differentiation of NSCs via the phosphorylation of stat3 signals and the expression of bHLH transcription factors.
Subject(s)
Astrocytes/cytology , Cell Communication/physiology , Neural Stem Cells/cytology , Animals , Astrocytes/metabolism , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Brain-Derived Neurotrophic Factor/metabolism , Cell Differentiation/physiology , Cell Growth Processes/physiology , Cells, Cultured , Culture Media, Conditioned , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Mice , Neural Stem Cells/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction , Tumor Necrosis Factor-alpha/metabolismABSTRACT
OBJECTIVE: The study was to evaluate the microscopic changes on skin and soft tissue after repeated expansion for clinical work. METHODS: Six little pigs were divideded as: conventional expansion group, repeated expansion group, and blank control group. Histologic, ultrastructure and bFGF of the skin were observed and measured in each group after samples had been made. RESULTS: The skin and soft tissue after repeated expansion were healthy on the whole. Compared with the conventional expansion group, there was more microscopic change in the repeated expansion group. Collagen fibers were injured evidently. Cells were injured slightly and proliferated much more, and moreover, they were more activated. The content of bFGF was more higher. CONCLUSIONS: The skin and soft tissue after repeated expansion are healthy on the whole by more growth and more repair though repeated expansion may result in more injuries. So repeated expansion is safe and feasible.
