| About 5% of all the patients suffering from craniocerebral trauma manifests an injury of the visual system, appropriately half of them would maintain permanent visual damage. It is very difficult to cure this problem, because visual nerves are the extension of protein and they are lacking in the abilities to repair and regenerate themselves after being damaged. For a long time, there have been arguments about the treatments of optic nerve injury. Conservative measures, drug treatments (steroid) and operations are all selective methods. But analysis of many clinicians shows that there are no significant difference in visual improvement between the patients treated with steroid alone, and those treated with surgical decompression alone or with no special treatment. Even in some surgical groups, no significant difference is found among clinicians operated upon at different times after they are visually injured. Furthermore, some problems such as doses ,timing and side-effects of some medicine, timing and adaption of operations have not been understood clearly. Therefore, seeking for effective measures to promote restoration and regeneration of optic nerve injury has become a hot topic in modern neurobiological field. Neural stem cells (NSCs), a kind of cells, are characterized by non-differentiation, multiplying and self-renewing abilities, which make themselves proliferate and differentiate into major kinds of central nerve system(CNS) cells (neurons and astrocytes and oligodendrocytes) and restoring traumatic tissues. NSCs are found in embryos and partial cerebral of grown mammal animals. Now there have been successful cases in curing some nerve system diseases and trauma by means of transplantation. There are few reports in the world about the employment of transplantation of NSCs in curing traumaticvisual nerve system. There is no literature about it in our country. In this experiment, 16-18d rat embryonic NSCs from ventricular zone / sub-ventricular zone (VZ/SVZ) were incubated and proliferated in vitro, then identified and implanted into the injuryed optic nerve of rats. NSCs were implanted at different times and after that the optic nerve was detected at different times to see the recovering effects of the ultrastructure and the visual transmitting abilities of the traumatic nerve. In this way, the effects of transplantation on the traumatic optic nerve are probed into.Methods The cells from VZ/SVZ of 16-18d rat embryo were dismissed with a polish-paster pipe, then cultured and proliferated in serum-free medium. Immunocytochemistry method was employed to test the positive expression of Nestine. Forceps-holder way was employed to make the model of traumatic rat optic nerve. The animals under experiment were divided into three groups: Group I -untreated, functioning as the negative group for comparison; Group II- treated with SOOAu bFGF (basic fibroblast growth factor), containing three subgroups: subgroup IIA (being injected with bFGF immediately after injury), subgroup IIB (being injected with bFGF after injury for 1wk) and subgroup IIC (being injected with bFGF after injury for 4wk); Group III- the treated group with NSCs, being injected with NSCs(lxl06 )in some parts, containing three subgroups as well: subgroup IIIA (being injected with NSCs immediately after injury), subgroup IIIB (being injected with NSCs after injury for Iwk) and subgroup IIIC (being injected with NSCs after injury for 4wk). Here Group I served as negative control and Group II as positive control. The optic nerve specimens were made after Iwk and 4wk respectively after operation and injecting. Then the specimens were sliced and observed with electronic microscope, at the same time the F-VEP (flash-visual evoked potential) was induced.Results (10 The cells cultured in vitro grew in a good state, identified to be positive by immunocytochemistry Nestine. (2) The ultrastructure changes of optic nerves: The normal optic nerve structure was clearly seen, the axons were in orderly arrangement and the myelin sheathe were clearly firm and... |
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