Experimental Study Of GelMA/PEDOT:PSS Conductive Hydrogel Loaded Neural Stem Cells On Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia and its secondary cerebral ischemia-reperfusion injury(I/R)often lead to neuronal damage and severe disability.Studies have found that neural stem cells(NSCs)transplantation can be beneficial to the functional recovery of the damaged brain tissue,and the possible mechanisms include cell differentiation,cell replacement,immune regulation,neural network reconstruction and release of trophic factors.However,direct NSCs transplantation has a low cell survival rate and low neuron differentiation efficiency,due to the changes in the internal microenvironment of brain tissue after brain injury.Herein,a conductive hydrogel composite based on gelatin methacryloyl(GelMA)and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)was developed as NSC niche for the cure of cerebral I/R.For the first time,the GelMA/PEDOT:PSS100 co-cultured with neural stem cells found that neural stem cells have better differentiation and proliferation,then the mRNA levels after 7 days showed that GelMA/PEDOT:PSS100 can promote the differentiation of neural stem cells into neurons.Further experiments found that GelMA/PEDOT:PSS/NSCs that co-cultured with oxygen-glucose deprivation/reperfusion(OGD/R)neurons can also reduce the apoptosis of neurons.Therefore,we further verified in vivo and found that GelMA/PEDOT:PSS100 hydrogel was easier to metabolize and absorb subcutaneously than GelMA hydrogel.It was found by HE staining that implantation of conductive hydrogel in normal brain tissue did not cause more inflammatory responses in the brain.It was found that GelMA/PEDOT:PSS100 conductive hydrogel-loaded NSCs attenuated reactive hyperplasia of astrocytes(GFAP)and microglia(ibal)in cerebral infarct tissues more than simply transplanted NSCs by immunofluorescence staining in animal model of middle cerebral artery ischemia-reperfusion(MCAO).We also confirmed in vivo imaging system(IVIS)that the survival rate of PKH26-labeled NSCs in GelMA/PEDOT:PSS100 hydrogel was significantly higher than that in GelMA hydrogel 7 days after transplantation.It was found that GelMA/PEDOT:PSS100 hydrogel loaded with NSCs could reduce the loss of neurons after cerebral I/R injury by immunofluorescence staining of neurons(NeuN)in the cerebral infarction area of MCAO rats.Through this experimental study,we co-cultured GeIMA/PEDOT:PSS/NSCs hydrogel complexes with neurons after OGD/R for the first time in vitro,and observed the neuroprotective effect of conductive hydrogel-loaded NSCs on neurons after OGD/R.At the same time,it is also the first time that GelMA/PEDOT:PSS hydrogel loaded NSCs was applied in an animal model of brain I/R injury,and the synergistic effect of GelMA/PEDOT:PSS hydrogel on neuroprotection and anti-inflammatory after NSCs transplantation was found,which is of great significance for expanding the application of conductive hydrogel in CNS diseases.It is shown that GelMA/PEDOT:PSS hydrogel has good application prospects as a niche for NSCs transplantation,and its electrical conductivity provides a basis for future research on the regulation of nerve cell growth and development by electrical stimulation.