Mechanism And Impact Of Self-assembling Peptide Material Promote Nerve Cell Growth And Development

Background and PurposeWith the development of modern society,accident injuries,war,earthquakes,cancer surgery cause neurological defects increase yearly.Peripheral nerve defects in all trauma patients in the incidence rate of about 2.8%,China's new nerve defect cases around 600,000 to 900,000 cases per year,need to repair nerve by nerve graft cases about 30 to 45 million cases of improper treatment if permanent disability,resulting in severe economic burden and social burden.Has been derived from neural transplantation to repair peripheral nerve defects ideal surgical method has been widely used in clinical practice,but also to measure a variety of neurological bridging material "gold standard",but often result in sensory nerve area donor,dysfunction,and autologous nerve limited sources,and therefore an urgent need for more clinically effective and safe source of extensive nerve graft material.In recent years,the development of tissue engineering technology for the treatment of peripheral nerve injury opened up a new way of thinking,the technology used in tissue engineering peripheral nerve regeneration and repair,trauma surgery in recent years,a hotspot.Neural tissue engineering to improve the repair of peripheral nerve defects brought new hope.Tissue engineered nerve biggest difference with nerve autograft in that they create a different regenerative microenvironment.To overcome the lack of natural nerve tissue engineering to create an environment conducive to the regeneration of peripheral nerve microenvironment,we have been trying to find a good solution.Cells in vivo microenvironment which is three-dimensional,and their movements are often influenced by local chemical signals or molecules.The traditional use of cultured cells in vitro interactions between cells and the adherent monolayer culture method,the researchers found that the cells in the culture method on a two-dimensional plane,can not simulate the spatial structure of the extracellular matrix(ECM extracellular matrix,),but can not reflect the effect of three-dimensional microenvironment in regulating a variety of signals to the cells.Therefore,the traditional culture methods often lead to changes in the biological characteristics of the cell fraction,and even lead to missing some key cellular phenotype and function.In the development of artificial nerve graft,natural biological materials are designed three-dimensional(3D)or hydrogels and further stent is designed to support neuronal survival,adhesion,proliferation and guide.This paper is available from natural materials silk inspiration,that bionics ideas,design and synthesis of fibroin polypeptide,hydrogels made of three-dimensional scaffold.Study on nerve cell growth and its impact and mechanisms of development.Methods1.SF16 polypeptide molecules are synthesized using automatic peptide synthesizer,SF16 analysis and purification by high performance liquid chromatography and mass spectrometry.SF16 molecules observed circular dichroism and spatial structure by 400 spectrophotometer and atomic force microscopy.Self-assembling peptide hydrogel material ultrastructure is detected by Scanning electron microscopy and atomic force microscopy.SF16 scaffold and PC12 cell were co-cultured together,then cell morphology and proliferation was observed by Inverted phase contrast microscope,and DNA content of each sample was measured by fluorescence spectrophotometer.Total RNA was extracted by fluorescence real-time quantitative PCR.Total proteins were extracted for protein level detection.SF16 scaffold was used to Sciatic nerve defects in animal models,and Evaluation of the effect of nerve repair is by electrical nerve physiology,nerve regeneration histological analysis of myelinated axon regeneration evaluation methodResultsThe Circular dichroism(CD)tests of SF16 polypeptide molecule showed a strong negative peak at 194 nm at a weak negative peak at 223 nm.Chemical structure and spatial structure of SF16 polypeptide formed after dissolved in deionized water,p H value of about 3.4 to produce a milky white translucent appearance.The rigid structure of the nanorods is observed by atomic force microscopy.Our results indicate that these nanorods diameter up to 80 nm,length of 5?m.SF16 peptide hydrogels exhibit sponge-like structure and the interlocking mesh structure by atomic force microscope.Cell Distribution fairly uniform,with the increase in the number of cells of the culture time increases gradually.On the seventh day,it can be observed in the collagen peptide hydrogel to a circular cluster of living cells.SF16 peptides and cultured in collagen hydrogel DNA content of PC12 cells as the culture time increases gradually increased.Highest DNA content were about 3.68 times and 5.19 times the saline group.High specificity is expressed by the PI3 K / AKT / m TOR signal for controlling cell growth and adhesion molecules in SF16 signal peptide hydrogel cultured PC12 cells,such as p70S6K1,4EBP1 and cadherin family(E-cadherin and N-cadherin).Animal experiments showed that the recovery of nerve conduction amplitude SF16 group was significantly higher than saline group.Schwann cell number and density of SF16 group was significantly higher than saline group,and regular extension.SF16 group compared to more regular arrangement of nerve fibers nerve defect with the saline group,the higher density.ConclusionsSF16 was successfully synthesized,can be self-assembled into a sponge-like structure,intertwined network structure of the gel material.SF16 hydrogel material can promote PC12 cell proliferation,adhesion and the regulation of cell signal transduction pathways.SF16 hydrogel scaffold as a simple matrix can promote axon regeneration and recovery of neurological function,and its possible mechanism is SF16 polypeptide may induce PI3 K / AKT / m TOR signaling pathway and further promote cell growth and proliferation.SF16 polypeptide may be a new and effective nerve tissue engineering scaffolds.