| The composite material PDLLA/β-TCP/PRGD/NGF which was designed to apply in nerve tissue repair could not only be able to provide support space for nerve regeneration, but also slow the release of nerve growth factor (NGF) which can induce differentiation of neural stem cells and the endogenous tissue repair mechanisms. It was suggested that the repair of nerve tissue between the material and autologous transplantation has no significant difference in functional effect and histological observation had showed that the number of new nerve fibers more than form Rules when the materials were used in the experimental neural tube defects of rat sciatic from the nerve electrophysiological results. These results strongly indicated that composites PDLLA/β-TCP/PRGD/NGF has application in neural tube enormous prospects. It is necessary to demonstrate the release of NGF play the leading role in the material material from Molecular biology microscopic point of view.PDLLA/β-TCP/PRGD/NGF which would be used in the nerve repair as an artificial nerve conduit material had two main functions:one was to provide a nerve repair of scaffold space, another was to provide a local micro-environment which can induce nerve regeneration and contain the continuous release of NGF and other substances. PC 12 cells derived from the brown rat adrenal pheochromocytoma which could generate a kind of sympathetic-like cells with continuous stimulation of the NGF. This feature was widely used in neurobiology research topic, and signaling mechanism that PC 12 cell differentiation could be induced by NGF was widely known. The formation of micro-environment in vivo could be approximately simulated by preparation of material extracts in vitro, and that the differentiation pathway which was involved in PC12 cell differentiation by micro-environment of extracts would play a great role in the materil stimulability and tmicroscopic mechanism of tissue regeneration. In the early stage of NGF induction of PC 12 cells, the protein ERK1/2 which played a key role in the differentiation, and the phosphorylation levels of the protein which could be detected by using ELISA and westernblot experiments were significantly increased. Previous studies showed that PC 12 cells were treated with the materials PDLLA/β-TCP/PRGD/NGF extract can differentiate and generate axons. The two experimental methods was used to detect the change of ERK1/2 phosphorylation levels by real-time during the extracts inducing PC 12 cells, at the same time the experimental control group PDLLA/β-TCP/PRGD extracts and negative control group without any treatment that PC 12 cells would be set. The results showed that the ERK1/2 phosphorylation could be increased during the extracts inducing PC 12 cells in the first 20min, and PDLLA/β-TCP/PRGD/NGF extraction contained NGF that was released from the materil in vitro played a great role in ERK1/2 phosphorylation significantly increased, also the other components which was released during the material degradation had a synergistic effect. This result showed that the role of these exogenous factors might occur as the leading factor in inducing.β-tubulin is the main ingredient of PC 12 cell axons, the typeⅢβ-tubulin expression could be increased by extracts sustained inducing, and this further demonstrated that the NGF of extract could induce the PC 12 cells differentiation. |
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