Expression Of Chondroitin Sulfate Proteoglycans In Retinae Of Retinal Degeneration Rats And Effects Of CSPGs Degradation On Photoreceptor Apoptosis

Objective:1. To study the expression of chondroitin sulfate proteoglycans(CSPGs) in theretinae of retinal pigment epithelium cell degenerated induced by sodium iodateintraperitoneal injection.2. To investigate the effects of chondroitinase ABC on photoreceptor apoptosisin the retinae of sodium iodate-injected rats.Methods:1. NaIO3(3%,100mg·kg-1) were intraperitoneal injected to rats to establish theretinal degeneration models. HE and Tunel assay were performed to evaluate the RPEdegenerated animal model; the expression of CSPGs in rat retinae were detected byimmunofluorescence; the expression of Versican mRNA was analyzed byretrovirus-polymerase chain reaction(RT-PCR).2.2μl chondroitinase ABC were injected into vitreous cavity of6rats7daysafter sodium iodate-injection. Meanwhile,2μl phosphat buffer liquid (PBS) wereinjected into vitreous cavity of another6rats as PBS control group. The left6iodate-injected rats and another6intact SD rats were left without vitreous injection asthe control groups. The expression of CSPGs were detected by immunofluorescencemethod; the expression of Versican mRNA of CSPGs was analyzed byretrovirus-polymerase chain reaction (RT-PCR) and tunel assay was performed toevaluate the apoptosis of photoreceptor cell3weeks after vitreous cavity injection.Results:1. HE showed the morphological retinal degeneration in rats after NaIO3injection. The apoptosis of photoreceptor appeared severer with development of retinal degeneration in rat retinae after NaIO3injection. The apoptosis rate were(32.33±2.34)%and (41.67±2.58)%14days and28days after NaIO3injection,separately, with statistical difference between the two groups(F=409.81,P＜0.01).CS-56appeared in photoreceptor outer segment debris zone(DZ), the outer nuclearlayer (ONL),the inter nuclear layer (INL)and the ganglion cell layer(GCL)14daysafter NaIO3injection and spread to the outer plexiform layers(OPL)28days afterNaIO3injection. With days increasing after NaIO3injection, CS-56fluorescencebecame stronger apparently in each layer. The expression of Versican mRNA,N-terminal fragment of CSPGs, in model animals were (1.02±0.06）, significantlyhigher than in the control rats(0.23±0.02)(F=487.23,P＜0.01).2.(1)CSPGs appeared slightly positive in choroid, the inter nuclear layer (INL)and the ganglion cell layer (GCL) in retinae of SD rats. CSPGs expressed apparentlystronger in each layers and spread to the outer nuclear layer (ONL) and the outerplexiform layers in retinae of rats4weeks after sodium iodate-injection. CSPGsexpression weakened obviously in each layers of retinae of rats after treatment withChABC enzyme. The expression of mRNA of Versican, N-terminal fragment ofCSPGs, were consistent with CSPGs expression, with (0.18±0.02) in intact SD rats,(0.92±0.03) in sodium iodate-injected rats without treatment,(0.98±0.06) in PBScontrol group and (0.30±0.01) in ChABC enzyme treatment group separately. Therewere statistical difference among each groups (F=562.01,P＜0.01) except between thesodium iodate-injected rats without treatment and PBS control group.(2)Thephotoreceptor apoptosis rate were (7.33±1.03)%in intact SD rats,(40.00±2.37)%insodium iodate-injected rats without treatment,(41.83±2.32)%in PBS control groupand (35.2±1.94)%in ChABC enzyme treatment group separately. There werestatistical difference among each groups (F=392.81,P＜0.01) except between thesodium iodate-injected rats without treatment and PBS control group.Conclusions:1. With days increasing after NaIO3injection, the range of CSPGs keptexpanding and the expression intensity became stronger apparently in rat retinae. 2. ChABC degrade most of the abnormally deposited CSPGs in the retinae ofsodium iodate-injected rats, alleviate the apoptosis of photoreceptor, and improve thewound restoration of retinae.