Experimental Study Of ChABC Microspheres For The Treatment Of Injuried Spinal Cord Of Rat

Objective: (1) To prepare the ChABC microspheres, and to investigate it'sgeneral properties, such as the morphous of the microspheres, the particlediameter distributions, the durg loading rate, the drug encapsulation rate, thedurg release properties for.further animal model. (2) To evaluate the effect oflocal delivery of ChABC microspheres on the regeneration and functionalrecovery of total transected spinal cord of adult rat.Methods: (1) Prepare the ChABC microspheres with double emulsionmethods. Investigate the morphous of the microspheres, the particle diameterdistributions of the microspheres by the scanning electron microscope andlaser particle size analyzer; the durg loading rate and encapsulation rate of themicrospheres, and the durg release properties at the salt solutions in vitro withenzymatic hydrolysis kinetics spectrophotometry. (2) Adult SD female rats,weight from 200g to 250g, are randomly divided into 5 groups: 1) normalcontrol group; 2) sham operation group; 3) lesion group: spinal cordtransection group in which the T₁₀ spinal cord is completely transected; 4)ChABC group: spinal cord transection with local delivery of ChABC; 5)Microspheres group: spinal cord transection group with local delivery of ChABC microspheres. 4 weeks post lesion, Immunohistochemistry and imageanalysis of CS56 were performed to assess the degradation of CSPGs andlocal delivery of ChABC. 10 weeks post lesion, TMRDA anterogradeneuronal tracing, behavioral evaluation, cortical somatosensory evokedpotential, Immunohistochemistry and image analysis of CS56, NF200, GFAPand GAP43 were performed to assess the status of neurological regenerationand fuctional recovery.Results: (1) The morphology and the particle size distribution of the ChABCmicrospheres were good: smooth, without accretion and within a narrowparticle size distribution; The average durg loading were 15.55±0.90%, theaverage durg encapsulation rate were 53.88±1.45; The ChABC microsphereshas good redispersibility after freeze drying; The cumulative durg release ratiowere 85.14% within 3 weeks, and with a stable durg release properties and fitfor the Weibull equations: Y=1-exp(exp(-1.617+0.7396*ln(X)))^-1,R2=0.9933. The ChABC released from the microspheres within 3 weeks canmaintain an therapeutic concentration for treatment of spinal cord injury ofadult rats. (2)BBB Locomotor Rating score for rats: 10 weeks post lesion,thereis an statisticly significantly different among lesion,ChABC and ChABCmicrospheres group and between microspheres and lesion group,betweenmicrospheres and ChABC group.(3)CSEP:10 weeks post lesion,the latentperiod of CSEP are delayed in ChABC microspheres group,whereas lesionand ChABC group has no sign of wave recorded.The deference is statisticlysignificant between normal group and microspheres group. (4)TMRDAanterograde corticospinal cord neuronal tracing: fluorescent density of 3 groupare significantly deferent,microspheres group is strong than ChABC group, ChABC group is strong than lesion group.(5)IHC of CS56:10 weeks postlesion, The sum of positive region area of microspheres group is significantsmall than ChABC group and lesion group. (6)IHC of NF200 and GAP43:The sum of positive region area of microspheres group is significantly broadthan lesion group. (7)IHC of GFAP: There is no statisticly difference amongmicrospheres, ChABC and lesion group.Conclusion: (1)ChABC-PLGA microspheres were prepared, which wassuitable for further experiment research of rats.(2)ChABC microspheres canpromote the regeneration and functional recovery and nerve conduction of ratwith transected spinal cord injury and is better than ChABC.(3)ChABCmicrospheres can continuously degradation CSPGs located among region ofspinal trod injury and is better than ChABC.(4)ChABC microspheres canupgrade Immunoreaction of the NF200 and GAP43 among region of spinalcord injury, thus the regeneration and functional recovery after spinal cordinjury are obvious. ChABC microsphere is better than ChABC for thetreatment of spinal cord injury.