Different behavior of neural stem cells on TCPS and PVA
Date Issued
2010
Date
2010
Author(s)
Wu, Wen-Hsin
Abstract
In this study, we explored the different behavior patterns of embryonic rat cortical neural stem cells on two biomedical polymer substrates¬¬—tissue culture polystyrene (TCPS) and polyvinyl alcohol (PVA). A previous study had found that neural stem cells could not survive on PVA and the material might inhibit their proliferation. By contrast, neural stem cells can continuously proliferate and survive on TCPS. Hence, the purpose of this study was to investigate what were the factors that determined the different behaviors of neural stem cells between TCPS and PVA given that they are both suspended in culture.
Based on the purpose of this study, four hypotheses were generated. First, since the proliferation of neural stem cells was not observed on PVA, it was reasonable to assume that neurospheres could undergo differentiate as proliferation was inhibited. According to our assessment, neural stem cells did not differentiate on PVA before cell death. Second, neurospheres in general would attach to poly-D-lysine (PDL) substrate, where they are transferred to after being pre-cultured on TCPS. However, it was found that neurospheres failed to attach to PDL as they were pre-cultured on PVA before being transferred to PDL. Therefore, a proposed hypothesis was that the surface charge of neurospheres reduced probably. Apparently, the decrease of surface charge of neurospheres was measured by cell electrophoresis. It maybe related to negateively charged sialic acids of NCAM on cell membrane. Third, to confirm the translocation of phosphatidylserine (PS) from the inner to outer membrane, which represented to cell apoptosis, annexin V and TUNEL assays were applied. The results had verified that apoptosis pathway was the way through which cell death was induced when being cultured on PVA. Further results showed that additional anti-apoptotic agents had no significant effect on the number of damaged cells when they were cultured on PVA. Therefore, the mechanism of the apoptotic pathway on neural stem cells remained unexplored. Lastly, we hypothesized that such a cellular apoptosis might the result of PVA slightly releasing to medium. Cell death also occurred when they were cultured in medium pre-treated with PVA substrate. It indicated that neural stem cells were wrapped around by the release of PVA, which caused cell death.
Subjects
neural stem cell
polyvinyl alcohol (PVA)
apoptosis
sialic acid
Type
thesis
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