| Objectives:Nonarteritic anterior ischemic optic neuropathy(NAION)is the most common acute optic neuropathy in the middle-aged and elderly population.Patients present with sudden monocular painless visual loss and visual field defects.So far,the exact pathogenesis of NAION is not fully understood.It is generally considered to be an ischemic disease caused by insufficient blood supply to the optic nerve head secondary to short circuit of the ciliary artery.It mainly causes the apoptosis of retinal ganglion cells(RGCs)and the infarction of optic nerve,and there is no effective treatment widely accepted by ophthalmic colleagues at home and abroad.The Rho-ROCK signaling pathway is an important signaling system in the central nervous system.It is widely involved in the growth,differentiation,migration and cell development of cells,and can inhibit the regeneration of optic nerve axons.Fasudil,a selective inhibitor of ROCK,blocks Rho kinase,inhibits Rho kinase activation,and ultimately promotes axonal regeneration by binding to the Rho kinase ATP site.In this study,the photodynamic method was used to prepare the NAION experimental animal model,and the appropriate dose of fasudil was given to observe the therapeutic effect of fasudil on the NAION rat model,in order to provide the basis and basis for clinical application.Methods:72 SD rats were divided into blank control,normal saline and fasudil by random number table,with 24 rats in each group.The blank control group was not modeled,and no intervention was given during the whole experiment and observation period.In the saline group and the fasudil group,the model was constructed using the combination of Rose Bengal(RB)and multiwavelength laser photodynamic method.After the successful preparation of rat NAION(rNAION),the fasudil group was given 10 mg/kg fasudil intraperitoneally,and the normal saline group was given the same dose of normal saline intraperitoneal injection until the observation period.12 rats in each group were used for HE staining of retinal paraffin sections on the 3rd,7th,14th and28th day after successful modeling.The morphological changes of each layer of the retina were observed,3 rats at each time point;6 rats in each group were used for toluidine blue staining of the semi-thin sections of the optic nerve on the 7th and 28th days after the successful modeling to observe the damage of the axon of the optic nerve,3 rats in each experimental group;6 rats in each group were used to observe the changes in RGCs density and survival rate on the 14th and 28th days after the successful modeling,and three rats in each experimental group,After binocular sampling,The method of Brn3a antibody labele the RGCs was used for immunofluorescence experiment,Confocal laser microscope observation and photography,The Image J Image analysis software was used to count,record the number of RGCs,and transform the density of RGCs,the ratio of the RGCs density of the right eye and the density of the left eye RGCs by the photodynamic method were recorded as the survival rate of RGCs,and finally statistical analysis was performed.Results:1.Retinal section HE staining observation resultsThe morphological changes of the retinal layers were not observed in the blank control group at each time point.In the saline and fasudil groups,the edema thickening of the retinal nerve fiber layer appeared on the 3rd day after modeling,and there was no significant difference.On the 7th day after modeling,the edema of the nerve fiber layer in both the normal saline group and the fasudil group subsided,and the loss of RGCs occurred in both groups.In the normal saline and fasudil groups,the number of RGCs decreased significantly on the 14th day after the model establishment,and the loss of RGCs in the saline group was higher than that in the fasudil group.2.Results of toluidine blue staining in the semi-thin section of optic nerveThe morphological changes of the optic nerve were not seen in the blank control group at each time point.In the saline group and the fasudil group,partial axonal edema and ulceration occurred on the 7th day after modeling,and there was no significant difference between the saline group and the fasudil group.In the saline group,on the 28th day after modeling,obvious neurofiber bundle disintegration,axon loss,and glial tissue proliferation occurred.On the 28th day after modeling,the degree of axonal loss and gliosis tissue hyperplasia were significantly lower in the fasudil group than in the saline group.3.Changes in RGCs density and survival rateOn the 14th day after modeling,the density of RGCs in the blank control,normal saline and fasudil groups were 2263±110 cells∕mm~2、1503±42cells∕mm~2 and 1827±57cells∕mm~2,respectively.There were significant differences in the density of RGCs between the groups(P<0.05).The survival rates of RGCs in the above three groups were 99.6%±0.4%、67.5%±3.5%and80.0%±5.0%,respectively.The survival rate of RGCs was statistically significant(P<0.05).On the 28th day after modeling,the density of RGCs in the blank control,normal saline and fasudil group were 2239±69cells∕mm~2、1078±102 cells∕mm~2 and 1511±64 cells∕mm~2,respectively.The comparison between groups showed statistical significance of the density of RGCs in each group(P<0.05).The survival rate of RGCs in the above three groups was99.6%±0.6%、47.8%±2.8%and 66.1%±3.0%,respectively.The comparison between groups showed statistical significance between the survival rates of RGCs of the three groups(P<0.05).There was no significant difference in RGCs density and survival rate between day 14 and day 28 after modeling in the blank control group(P>0.05),while there was significant difference between normal saline group and fasudil group(P<0.05).Conclusion:Fasudil inhibits axonal apoptosis and reduces retinal ganglion cell loss in the NAION rat model. |
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