| Objective: Spinal cord ischemia-reperfusion injury(SCII)is a kind of secondary injury of thoracoabdominal aortic aneurysm and aortic dissection operation.Paraplegia or paraparesis caused by temporary or permanent spinal cord ischemia during operation is one of the most serious and unpredictable complications.According to statistics,the incidence of spinal cord ischemia and paraplegia after repair of thoracic and abdominal aortic aneurysm(TEVAR)is between 2.5% and 8%.The prevention and treatment of ischemic spinal cord injury is one of the most urgent problems in macrovascular surgery.Exosomes play an irreplaceable role in intercellular communication.They can regulate the biological activity of receptor cells by carrying proteins,nucleic acids and lipids.Astrocytes release neurotrophic factors and other signal molecules through a variety of ways to interact with other cells in the central nervous system,which plays an important role in maintaining the stability of the central nervous system.In this study,rat astrocytes were cultured in vitro,treated with ischemia preconditioning and extracted their exosome,then intrathecally injected into the rat spinal cord ischemia-reperfusion injury model,to observe the protective effect of the astrocytes exosome of ischemia-preconditioned on the spinal cord ischemia-reperfusion injury,so as to provide a new means for improving the protective effect of spinal cordMethods: The rat spinal cord astrocytes were cultured in vitro and given ischemic pretreatment.The supernatant was collected and the exosomes of the astrocytes were extracted by ultracentrifugation.The size and morphology of the exosomes were observed by transmission electron microscopy,and the exosomes were detected by wsstern blot.A rat model of spinal cord ischemia-reperfusion injury was established.The thoracic aorta was clamped at the beginning of left subclavian artery for 14 minutes.Healthy male SD rats were randomly divided into 4 groups,15 rats in each group: sham group,control group,exo group,IPC exo group.Sham group only opened the chest without spinal cord ischemia.PBS(10ul)was injected into the sheath one day before the operation in the other groups,and cultured under normal conditions The secretory body(10ul,2mg / ml)and the astrocyte exocrine body(10ul,2mg / ml)were pretreated by ischemia.The expression of Bax,Bcl-2 and cleared caspase-3 in the spinal cord was detected 6 hours after the operation.The motor function of hind limbs was evaluated before the operation,1 day,2 days and 7 days after reperfusion.The L4-6 spinal cord was taken from the rats after the last behavioral evaluation,and the pathological injury of spinal cord was evaluated by he and Nissl stainingResults: After the culture and passage of rat spinal astrocytes,many long and branched processes can be seen in the cell body.The cell morphology is regular and the size is uniform under the light microscope.Under transmission electron microscopy,the exosomes were found to be vesicles with diameters of 50-150 nm,which were round or oval.The surface marker proteins CD9 and CD81 were detected by Western blot.Compared with sham group,the proximal and distal arterial pressures of other groups decreased significantly(P < 0.05);compared with control group,the motor function scores of exo group and IPC exo group decreased(P < 0.05),and IPC exo group had the lowest motor function scores.Nissl staining showed that the number of neurons in exo group and IPC exo group was significantly higher than that in control group(P < 0.05).The expression level of Bcl-2 in exo group and IPC exo group was significantly higher than that in control group(P < 0.05),the expression level of Bax and cleaved caspase-3 in IPC exo group was significantly lower than that in exo group(P < 0.05).Conclusions: In this experiment,a convenient and economic model of spinal cord ischemia-reperfusion injury was established to simulate the spinal cord ischemia during the operation.It was confirmed that the spinal cord astrocyte exosomes had a protective effect on the spinal cord ischemia-reperfusion injury,and the astrocyte exosomes which were pretreated by ischemia could enhance the protective effect,and the mechanism may be related to the inhibition of neuronal apoptosis and inflammatory response after spinal cord ischemia,which provides a new way to improve the protective effect of spinal cord... |
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