| Primary open angle glaucoma(POAG)is the first irreversible blinding eye disease in the world and the second in China,which permanently damages optic nerve and retinal ganglion cells.There is still no medicine or surgical methods to cure it.In recent years,with the appearance of optical coherence tomography angiography,vascular factors have become the focus of POAG research.The lamina cribrosa is the key part of optic nerve ganglion cell injury.In the past,most of the studies were about the structural changes of lamina cribrosa.It was thought that the lamina cribrosa of POAG was thinner and had localized damage,but there was little research on the vascular density of lamina cribrosa.To research the pathogenesis of POAG,this dissertation established a kind of ischemia model of lamina cribrosa in rhesus monkeys,compared the lamina cribrosa vascular density of POAG patients in different periods and established a cell model of glaucoma in vitro.The research methods and results of this dissertation are as follows:1.Morphological study of lamina cribrosa ischemia and glaucomatous optic neuropathy in rhesus monkeys.Moderately mechanically block the branches of the short posterior ciliary artery on the nasal side of rhesus monkeys,the circulation of Zinn-Hallar ring was disturbed and lamina cribrosa ischemia was induced.The changes of intraocular pressure,vascular density of lamina cribrosa and thickness of optic nerve fiber layer were compared pre-and postoperative.The correlation between vascular density of lamina cribrosa and optic nerve fiber layer was analyzed.The eyeballs of rhesus monkeys were removed at the third month postoperative and pathological sections were made for immunohistochemical staining.Results:(1)Compared with the control group pre-and postoperative,the intraocular pressure of the experimental group was in the range of12～20 mm Hg,and there was no statistical significance(P>0.05).(2)There was segmental ischemia in the lamina cribrosa,and the difference between the experimental group and the control group postoperative was statistically significant(P<0.05).There was no significant difference between the control group pre-and postoperative(P > 0.05).(3)There was no significant change in the thickness of RNFL above,below and on the temporal side of the optic disc,and there was no significant difference in the thickness of RNFL on the nasal side between the two groups before and one week postoperative(P > 0.05).The difference was statistically significant at 1 month,2 months and 3 months postoperative(P<0.05).(4)Person’s correlation analysis showed that there was a significant correlation between the lamina cribrosa vascular density and the RNFL thickness of the nasal optic disc preperative,1st month and 3rd month after operation(P<0.05),but there was no significant correlation between them at 1st week and 2nd month postoperative(P>0.05).(5)Immunohistochemical staining showed that the control group was almost completely phosphorylated,while the nerve filaments on the temporal side in the experimental group were moderately phosphorylated,while most of them on the nasal side were dephosphorylated.Compared with the temporal side,the loss of axons on the nasal side was significant.2.Research on the correlation between lamina cribrosa vascular density and optic nerve damage in POAG patients.The sex,age,body mass index,best corrected vision acuity,C/D ratio,intraocular pressure,visual field,macular vascular density,macular optic ganglion cell complex thickness,optic disc vascular density,optic disc RNFL thickness,lamina cribrosa thickness,lamina cribrosa vascular density were compared,and the correlation between lamina cribrosa vascular density and these parameters was analyzed.Results:(1)No significant difference in sex,age,body mass index of each group.The best corrected visual acuity and C/D value were significantly different in each group(P<0.05).(2)The IOP of the control group was within the normal range,and the average IOP of the suspected POAG group was at the upper limit of the normal range of IOP.The average IOP of the POAG group was higher than that of the control group,and it showed a gradual increase trend in the early,middle and late stages.(3)Comparing the visual field index and MD between the control group and the suspected POAG group,the absolute value of visual field index and MD of POAG patients decreased and increased with the progress of the disease.(4)The macular RNFL,GCIPL and GCC thickness among the groups were analyzed by variance,and the differences were statistically significant(P>0.05).(5)The macular vascular density and optic disc vascular density of POAG patients decreased gradually with the progression of the disease,which were positively correlated with the thickness of optic disc RNFL.(6)The vascular density of lamina cribrosa in patients with suspected POAG and early,middle and late POAG was lower than that in normal people(P<0.05),and gradually decreased with the progression of glaucoma.Person’s correlation analysis showed the vascular density of lamina cribrosa was significantly correlated with visual field and p RNFL in the late stage of POAG.3.YAP and TAZ mediate steroid-induced alterations in the trabecular meshwork cytoskeleton in human trabecular meshwork cells.Human trabecular meshwork(HTM)cells were treated with different concentrations of dexamethasone(DEX),and then transfected.Yes-associated protein(YAP)and transcriptional coactivator with PDZbinding motif(TAZ)genes were knocked out and overexpressed,so as to explore their roles in the regulation of dexamethasone-induced glaucoma and determine the regulatory effects of YAP and TAZ on the proliferation and cytoskeleton structure of human trabecular meshwork cells.Results:(1)DEX changed the structure of F-actin in a concentration-dependent manner and promoted the formation of cross-linked actin network(CLAN)in HTM cells.DEX could induce the expression of YAP and TAZ in human trabecular meshwork cells increased,and DEX had a dose-dependent relationship with the transcription and expression level of YAP and TAZ.(2)DEX could induce the expression of β-catenin in cultured HTM cells.Compared with the control group treated with DEX,the expression of β-catenin in DEX-treated cells transfected with YAP and/or TAZ si RNA decreased.(3)The proliferation ability of cells with both YAP and TAZ genes knocked out decreased obviously,suggesting that YAP and TAZ could induce the proliferation of human trabecular meshwork cells.(4)CLAN formation of HTM cells transfected with YAP si RNA and TAZ si RNA is weakened,suggesting that YAP and TAZ regulate CLAN formation of human trabecular meshwork cells;(5)The permeability of single-layer HTM cells treated with DEX was impaired,and the permeability of cells transfected with YAP and TAZ expression plasmids was significantly reduced.YAP and TAZ regulated the aqueous outflow of human trabecular meshwork cells.To sum up,in this dissertation the animal model of ischemic glaucoma was successfully established.The vascular density of the lamina cribrosa in rhesus monkeys decreased,and the axons in the optic nerve in the corresponding area were damaged.There was a significant correlation between the vascular density of the lamina cribrosa and the thickness of RNFL decreased.The vascular density of optic disc,macula and lamina cribrosa in glaucoma patients decreased with the progress of the disease.YAP and TAZ participate in the changes of HTM cytoskeleton.These results improve the understanding of the pathogenesis of POAG and provide ideas for clinical treatment. |
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