| Spinal cord injury is a devastating condition,which can cause irreversible sensory-motor deficits and sphincter dysfunction below the injured segment.Those injuries not only affect the physical and psychological well-being of those patients,but also bring huge socioeconomic burden to their families and society.With the development of modern industry and transportation and the coming of the aging society,the cases of spinal cord injury have increased year by year.Although modern medicine and surgical techniques have made great progress,it is still believed that spinal cord injury is still an unhealed injury.Neuroprotection and nerve regeneration are two important aspects in the treatment of spinal cord injury.Neuroprotection is a way to reduce secondary injury after primary spinal cord injury by regulating the secondary pathophysiological changes.Neuro-regeneration refers to transplantation or stimulating its own cells to repair injured spinal cord.Stem cell transplantation therapy holds the potential to promote repair and functional plasticity following spinal cord injury,but the death and apoptosis of transplanted stem cells in the early stage of transplantation affect it’s therapeutic effect.How to improve it’s therapeutic effect is one of the problems.Free radicals are one of the crucial factors that affect the survival of transplanted cells.Therefore,reducing the level of free radicals may promote the survival of transplanted stem cells and improve the effect of stem cell transplantation for spinal cord injury.One of the best validated secondary injury mechanisms in acute spinal cord injury concerns the post-traumatic generation of free radicals and their oxidative damage.Free radicals induce a series of cascade reactions,so the injury expands.Early antioxidant therapy can effectively prevent the spread of the damage and regulate the inflammation.Superoxide dismutase(SOD)is a natural free radical scavenger in human body.So it was expected to be used in the treatment of SCI.However,because of the biological barrier,it is not allowed to enter into cells,which affects its clinical application.Recently,a 21-residue peptide carrier,PEP-1,was developed as a tool for delivering biologically active molecules into cells.This peptide carrier allows the delivery of a variety of peptides and proteins into cells in a biologically active form.A recent report demonstrated that the PEP-1-SOD1 fusion protein can be delivered both efficiently and in a biologically active form into injured spinal cords in vivo.Systemically injected PEP-1-SOD1 can decrease the levels of free radicals,and thereby can improve functional recovery after SCI.Objective To investigate the effects of PEP-1-SOD1 on adipose-derived stem cells(ADSCs)transplantation in the therapy of spinal cord injury(SCI).To discuss the antioxidant effects of PEP-1-sodl on early spinal cord injury and transplanted adipose derived stem cells.Methods ADSCs were isolated from the adipose tissues of rats,cultured in vitro,fluorescence-activated cell sorting(FACS)analysis was done to access the phenotype of ADSCs.of ADSCs were performed to identify the Multidirectional differentiation potential of ADSCs were ADSCs were identified by Osteogenic,adipogenic and chondrogenic differentiation induction in vitro,than it was infected with adenovirus carrying GFP gene and its biological characteristic was accessed.Rats were randomly divided into four groups sham group saline group,ADSCs groupPEP-1-SOD 1-ADSCs group.The saline group underwent sterile saline injection;The ADSCs group transplanted ADSCs after SCI.The PEP-1-SOD1-ADSCs group treated with PEP-1-sodl combined ADSCs transplantion.After 1,3 and 7 days,the SOD activity in spinal cord was assessed by pyrogallol autoxidation assay;MDA content was determined using thiobarbituric acid colorimetric method and apoptosis were detected by TUNNEL staining.At 1,2,3 and 4 weeks after operation,the BBB exercise were scored,NeuN expression was assessed by immunohistochemistry and GFP positive cells were determined by fluorescence microscopy.Results 1.ADSCs obtained by the Adherent culture had strong proliferation ability The FACS analysis showed that ADSCs exhibited some parallel characteristics of typical MSCs and null expression of hemopoietic stem cell marker.ADSCs had osteogenic,adipogenic and chondrogenic differentiation potential.2.Adv-GFP infected ADSCs showed bright circular,the proliferation ability was not impaired.3.1,3and 7days post surgery,the SOD activities of PEP-1-sod 1-ADSCs group was stronger than ADSCs group(P<0.05),the MDA levels of PEP-1-sod 1-ADSCs group was less than ADSCs group(P<0.05).1 days post surgery,the SOD activities of Saline group and ADSCs group was of no statistic differences.3and 7days post surgery,the SOD activities of Saline group was less than ADSCs group.4.7 days post surgery,there was less apoptotic cells in PEP-1-sodl-ADSCs group than ADSCs group(p<0.05),apoptotic cell numbers in ADSCs group was less than saline group(p<0.05).5.The BBB scores of SCI group were not significantly different 1 week after surgery,2,3,4weeks after surgery the BBB scores were descendingly ordered as PEP-1-sodl-ADSCs group<ADSCs group<saline group(P<0.05).6.4weeks after surgery Groups comparison of NeuN positive cells were for PEP-1-sodl-ADSCs group>ADSCs group>saline group(P<0.05),the GFP positive cells of PEP-1-sodl-ADSCs group was higher than that of ADSCs group(P<0.05).Conclusions 1.high purified ADSCs can be obtained by adherent method.The obtained cells showed MSCs surface markes and had multi-directional differentiation capbilities.Adv-GFP infected ADSCs showed bright circular,its proliferation ability was not impaired.2.compared with purely ADSCs transplantation,PEP-1-SOD1 further increased the activity of local SOD,decreased the content of MDA.3.PEP-1-SOD1 reduced the early Apoptosis of local and transplanted cells.4.PEP-1-SOD1 improved the effects of ADSCs transplantation to repair SCI.5.It demonstrated synergistic effect of PEP-1-sod1 combined adipose stem cell transplantation in the treatment of spinal cord injury;it might relate to the antioxidant and anti-apoptosis effect of PEP-1-sod1. |
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