| Objective:Optic nerve injury is a common ophthalmic disease, it often cause serious decline or lose of vision, and its treatment effect is bad. At Present,drug therapies is the main methods to this disease.But drug therapies has problem of price and side effect,and its treatment effect is not ideal.This years, the incidence of this disease increases gradually,so we have to find a new cheap, effective neural protection medicine without side effects Progestrone (PROG) is a neural steroids, its effect of nerve protection in brain damage and peripheral nervous system has been confirmed.Its effect of anti-inflammation, resistance to apoptosis and ischemia has been payed more and more attention.It has become a hotspot in the nerve protection drugs.The pathology base of visual function decline in optic nerve injury is the progressive damage in the retinal ganglion cells (RGCs).After the optic nerve injury,ischemia and hypoxia caused by artery spasm and axoplasmic transport obstacles caused by the cytoskeleton damage is the the important factor in RGCs apoptosis. Microtubule associated protein-1B(MAP-1B) is a important cytoskeleton protein to maintaining normal form of cell keleton and axons growth. Calcitoningene-related peptide (CGRP) is a biological active peptides,can protect the neurons by expanding the blood vessels and adjust ion concentration.This study employs PROG as the optic nerve protective agent, MAP-1B and CGRP as the detect factor, to study the neuroprotective effects of PROG on RGCs after optic nerve injury in rat by observing MAP-1B and CGRP. In the present study,we try to provide an experimental evidence for new means on optic nerve protection.Methods:sixty SD rats were divided randomly into three groups, normal control group, experimental control group and experimental treatment group.20in each group。The rat's right optic nerve was crushed with a pair of cross-action forceps with pressure of148.Og. After this, progesterone was injected intraperitoneally with8.0mg/kg in experimental treatment group. Balance normal saline was injected intraperitoneally in experimental control group. In1day,3days,7days,14days,28days after injury, the histological changes of the retina ganglion cells were observed in2mm range above the optic disc. The morphological and number changes of the retina were observed by light microscope,and the MAP-1B and CGRP were stained and analyzed with immunohistochemical method. All date were presented as (x±S),differences were calculated by one-way ANOVA within-group, by paired-samples t-test between-group.The statistical analysis was described by SPSS13.0software.p<0.05was considered statistically different and P<0.01was significantly statistically different.Results:1.The observation of microscope in retinaIn the normal control group adult rat retina under HE dyeing has three layers of the nucleus, from the vitreous to the sclera is the RGCs layer, bipolar cell layer, photoreceptor cells layer.RGCs layer of cells are single of arrangement, size is different and outline is irregular.After the optic nerve injury, both groups number of RGCs continuously reduce with the passage of time. And the number of RGCs reduces quickly in14days, after14days the reduce speed became slow.The number of RGCs in the experimental treatment group was higher than that in the experimental control group(P<0.01). The numbers of RGCs in the experimental control and experimental treatment groups were lower than normal control group. Their differences were significant (P<0.01).(Table1, Fig21)2. Immunohistochemical staining of MAP-1B in retina ganglion cellsIn normal control group,MAP-1B mainly present in the photoreceptor inner segment and the cell body in tan-yellow color,also a few express in the photoreceptor outer segment and cytoplasm in pale yellow.After optic nerve injury, MAP-1B express much more than normal in tan-yellow color.After optic nerve injury, both groups express MAP-1B weakly. Both groups began to express MAP-1B in3days. Expression of MAP-1B in the experimental treatment groups was gradually increasing during14days, and decreasing obviously at28days. And expression of MAP-1B in the experimental control groups was gradually increasing during7days, and decreasing obviously at14day.(Table2, Fig22)3. Immunohistochemical staining of CGRP in retinaIn normal control group,CGRP mainly present in the inner plexiform layer and the outer plexiform layer in tan-yellow color, also a few can express in the cytoplasm in pale yellow. CGRP express much more than normal in tan-yellow color.After optic nerve injury, both groups express CGRP gradually increasing during7days, on7day expression were strongest. After7days, both groups express CGRP gradually reduce until28days. After the optic nerve injury3day,7day,14day,28day retinal ganglion cells CGRP expression of the experiment treatment group were higher than that of the experiment control group, there is a difference of statistical.(Table3, Fig23)Conclusion:1.There were retinal ganglion cells damage and apoptosis in early optic nerve injury, and intraperitoneal injection of PROG can reduce retinal ganglion cells damage, and made retinal ganglion cells apoptosis slowly.2.In the early time of optic nerve injury,expression of CGRP in the retina ganglion cells is significantly higher, and intraperitoneal injection of PROG can increase the expression of CGRP in the retina ganglion cells. It shows that CGRP were involved in the optic nerve injury and repair process, mechanism of PROG to protection the optic nerve injury were related to CGRP.3.After the optic nerve injury, expression of MAP-1B in the retina ganglion cells is significantly higher, and intraperitoneal injection PROG can increase the expression of the MAP-1B in retina ganglion cells. It shows that MAP-1B were involved in the optic nerve injury and regeneration process.Mechanism of PROG to protect optic nerve injury, promote the myelin regeneration maybe related to the increase the expression.of cell skeleton protein MAP-1B 4.The results shows that PROG can reduce retinal ganglion cells damage in the early stage of optic nerve injury,and that protect effection maybe by increasing the microtubules related proteins and calcitoningene-related peptide,so as to provides a new approach of treatment in the early stage of optic nerve injury... |
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