| Objective:(1) To investigate the repair mechanism of optic nerve injury and to know the action of Macrophage cells in order to provide theoretical basis for new treatments of optic nerve injury when the lens being injured, by founding a new kind of animal model of optic nerve injury in rabbit.(2) To observe the transplantation and existence of Schwann cells in body through the MRI and applying SPIO and investigate its characteristics, in order to widen the application scope of MRI.Methods:Thirty-two healthy male Chinese white rabbits and Thirty-two healthy female Chinese white rabbits were used in this study, weight2-2.5kg. These Chinese white rabbits’eyes were divided into2groups:the study group (optic nerve injury and lens injury) added up to64right eyes, and the control group (only optic nerve injury) added up to64left eyes. The study group and the control group were randomly divided into8sub-groups with8eyes in each by the time of1,2,4,7,10,14,2l,28days after injury and were injected with SPIO(0.2mmol/kg) through their ear vein0,1,3,6,9,13,20,27days after injury. These eyes were used for flash-visual evoked potential(F-VEP) examine before injury and1,2,4,7,10,14,21,28days after injury and used for optic nerve MRI and retinal histopathology and Immunohistochemistry examine1,2,4,7,10,14,21,28days after injury.Results:(1)F-VEP:In study group:During the first10days after injury the latency of P100became longer (P<0.05) and then became shorter after that (P<0.05), and the amplitude became lower during the first7days after injury (P<0.05) and rebound after that (P<0.05). In control group:During the first14days after injury the latency of P100became longer (P<0.05) and had a trend of shortening after that (P<0.05), and the amplitude became lower during the first14days (P<0.05) and had a trend of rebound after that, but the rebound was not significant (P>0.05). The changes of amplitude on28days after injury were significant between the study and control groups (P<0.05).(2)Optic nerve MRI:The optic nerve showed middling signal and the orbital structure was ordered before injury.1day after injury, the lens structure was disordered in the right eye,and high signal could be seen on optic nerve2.0-4.5mm posterior to the globe in both eyes, and the structure in orbit was disordered;10days after injury, many low signal could be seen on the around of the optic nerve in the right eye, but high signal could be seen on the around of the optic nerve in the left eye yet, and optic nerve the disordered structure in orbit tended to be stable;28days after injury, the injured segment of optic nerve in left eye still showed little high signal and the signal of optic nerve on the globe side of the injury part was uneven.(3)Retinal histopathology:In study group,4days after injury, the activation Macrophage cells became fewer, large amount of RGCs without nucleus could be seen, and10days after injury, the number of activation Macrophage cells reach peak then drop off;28days after injury, the activation Macrophage cells vanished. In control group, during28days after injury, the activation Macrophage cells was not been seen yet. In study group,4days after injury, the reborn RGCs could been seen in the retinal tissue, and after that the number increased slowly. In control group, the reborn RGCs could not been seen in the retinal tissue in each sub-groupsConclusions:(1) The activation Macrophage cells can promote the existence and rebirth of RGCs and plays an important role during the repair after optic nerve injury, so the promotion of Macrophage cells soakage may be a promising way to save optic fibers in the future.(2) Optic nerve MRI can show the injured part of optic nerve accurately and can reflect the degree of the repair by showing the transplantation and existence of Macrophage cells in tissue with SPIO. |
PDF Full Text Request