| OBJECTIVE: Most studies have combined tissue engineering materials with stem cells or factors to improve the microenvironment of animal spinal cord injury models in order to increase the duration of action,improve the recovery effect and prognosis.1.Make PD-SHH-Fibrin scaffold and explore its slow-release effect and characteristics.2.Construct the SD rat spinal cord injury model,transplant PD-SHH-Fibrin scaffold,observe the positive rate of related spinal cord growth protein,and evaluate the repair effect.METHODS:1.Using vacuum freeze dryer to make Fibrin scaffold.After the preparation is completed,it is placed in a dopamine hydrochloride solution with a PH = 8.5 for 24 hours for cross-linking,and then the cross-linked scaffold is placed in SHH solution to adsorb and cross-link for 24 hours.After 24 h,the ELISA kit was used to measure its sustained release performance.2.60 8-week-old female SD rats were taken to establish spinal cord injury model and randomly divided into 4 groups: no materials were implanted in group A,Fibrin scaffolds were implanted in the injury group B,and Fibrin-PD scaffolds were implanted in the injury group C PD-SHH-Fibrin scaffold was implanted in the injured part of group D,and the BBB score was performed within 12 weeks after operation;12 weeks after surgery,the tissues of the injured spinal cord were taken for histological observation(hematoxylin-eosin and immunohistochemistry)and Weston blot detection.3.40 8-week-old female SD rats were taken to establish spinal cord injury model and randomly divided into 4 groups for treatment: no material was implanted in group A,Fibrin scaffold was implanted in the injury group B,and Fibrin-PD scaffold was implanted in the injury group C PD-SHH-Fibrin scaffold was implanted in the injury of group D.Six weeks after surgery,a second operation was performed.Fluoro-gold was injected 1 cm below the transverse section.After 4 weeks,the entire length of the spinal cord was removed,and the number of positive cells labeled with Fluoro-goldwas observed under a microscope using continuous frozen sections.4.Forty 8-week-old female SD rats were taken.Before the injury model was established,each rat was electrophysiologically observed to observe the electrophysiological conditions of the lower extremities,including Somatosensory evoked potential and Motor evoked potential.Subsequently,the rat spinal cord injury model was established and randomly divided into four groups: no material was implanted in group A,Fibrin scaffold was implanted in group B,PD-Fibrin scaffold was implanted in group C,and PD-SHH-Fibrin scaffold was implanted in group D.At8 weeks after surgery,through the detection of SEP and MEP,the recovery of rat lower limb movement and sensation was observed.RESULTS:1.Within 16 days of observing the scaffold,SHH release was slow in the early 5 days,and the scaffold did not show sudden release of factors on the first day.It showed rapid release in the next 7 days and was completely released in the last 4 days.On the last day,the scaffold disintegrated and showed a faster SHH release rate.2.From 2 weeks after operation,the lower limb motor function of each group began to recover.The BBB score of group D after 5-12 weeks was higher than that of the other3 groups(P <0.05).The lower limb motor function of group D recovered best;3.Hematoxylin-eosin staining showed that new nerve fiber tissues were seen in groups C and D,and the amount and density of new nerve fiber tissues in group C were lower than those in group D;4.Immunohistochemical staining showed that a large number of linearly arranged new nerve fibers were observed in the cross section of group D.The positive rates of myelin basic protein(MBP),growth-related protein(GAP43)and neurofilament protein(NF200)were higher than those of the other 3 groups.The positive rate of glial fibrillary acidic protein(GFAP)is lower than that of the other three groups;5.Western blot analysis showed that MBP,GAP43 and NF200 in group D were higher than those in the other 3 groups(P <0.05),and GFAP expression was lower than those in the other 3 groups(P <0.05);6.The results of Fluoro-gold retrograde tracing showed that more positive nerve fiberspassed through the injury area of the PD-SHH-Fibrin group,and the amount of Fluoro-gold was significantly better than the other three groups.7.The latency and amplitude of somatosensory evoked potentials and motor evoked potentials in the electrophysiological PD-SHH-Fibrin scaffold group were significantly better than those in the other three groups.CONCLUSION: The PD-SHH-Fibrin scaffold shows good biocompatibility and has a sustained and stable slow-release effect.The scaffold obviously promotes the repair of spinal cord injury in rats.PD-SHH-Fibrin scaffold can significantly promote the repair of spinal cord injury in rats. |
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