| Objective: Diabetic retinopathy (DR), a common severe complication of microvascular diabetes , is one of the leading causes of blindness。Its pathogenesis is not yet very clear. In recent years, the study found that in DR, there are many factors involved in inflammation, so it was suggested that DR is an inflammatory disease. Nuclear factor-κB,also called nuclear factor kappa binding(NF-κB),is thought of as a central switch to control expressions of many target genes.Many stimulated signals can active NF-κB to participate in cellular apoptosis and inflammatory reaction,NF-κB mediates the survival to prevent the death and inflammatory reaction,of cell through the pathway involving Toll-like factor receptor. Toll-like receptors (TLRs) are a family of innate pattern recognition receptors (PRRs) that recognize conserved molecular patterns.The signaling pathways induced by TLRs play an important role in the innate response.More researches on the expression of TLRs in cell and organizes of eye have been]carried out. There is close correlation between the discovery of the TLRs in eye and ocular immune response and inflammation.The medicine which can depress the activation of NF-κB signaling pathway are important therapeutic agents for DR. Oxymatrine is our tradition medicine main ingredients of Sophora alopecurorides, Sophora flavescens and Kwong bean root. Abundant of pharmacology and clinical research find that oxymatrine(OMT) has NF-κB- inhibition ,anti-inflammatory and anti-apoptosis effects. It can significantly reduce serious side effects. Rats were used to establish diabetic models with streptozocin, our experiment observed the expression of TLR4 and NF-κB in rat model of retina; investigated the retina protective effects of OMT and the relationship between its retina protection and inhibition of NF-κB signaling pathway. This study will explore inflammatory factors in the pathogenesis of diabetic retinopathy further.Methods: Thirty health male rats of SD were used to establish diabetic models with streptozocin by intraperitoneal injection and were randomly divided into experimental control group (N = 15) and experimental group (N = 15). Experimental rats by oral gavage of OMT 100mg/kg, once a day until the end of the experiment. Experimental control group was given the same dose of normal saline. Another fifteen normal rats were in blank control group and this group did not take any interventions. At the end of the third month, kill the rats by overdosing intraperitoneal injection of chloral hydrate, then take off the retina tissue. NF-κB and TLR4 expression were measured by immunohistochemistry and RT-PCR. Completing statistical analysis by SPSS13.0 statistical software.Results:1 The results of light microscope observation: in blank control group ,rat retinal tissue neatly arranges on each floor. In retinal tissue of experimental control rats, the number of retinal ganglion cells decreases significantly than the blank control group. There was significant difference(.t=19.615, P < 0.01). Retinal layers arranged irregularly. In retinal tissue of experimental rats, the number of retinal ganglion cells increases significantly than the experimental control group. There was significant difference(t=27.674, P <0.01). Retinal layers arranged irregularly slightly.2 The immunohistochemistry of TLR4 in the blank control group showed weak positive reactions. However, the immunohistochemistry of TLR4 in experimental control group showed strong positive reactions. The expressions were highter than those in blank control group. There was significant difference(t=13.544,P < 0.01). The immunohistochemistry of TLR4 in experimental group showed weaker positive reactions than experimental control group. There was significant difference(t=20.920, P < 0.01).The trends of changes with mRNA expression were similar to immunohistochemistry. The expressions of TLR4mRNA in experimental control group were highter than those in blank control group. There was significant difference (t=15.09,P < 0.01). The expressions of TLR4mRNA in experimental group were lower than those in experimental contro group. There was significant difference(t=31.972,P < 0.01).3 The immunohistochemistry of NF-κB in the blank control group showed weak positive reactions in ganglion cells layer,inner nuclear layer and outer nuclear layer. The immunohistochemistry of NF-κB in experimental control group showed strong positive reactions in ganglion cells layer,inner nuclear layer and outer nuclear layer. The expressions were highter than those of blank control group. There was significant difference(t=14.364, P < 0.01).The immunohistochemistry of NF-κB in experimental group weaker positive reactions than experimental control group. There was significant difference (t=27.107,P < 0.01).The trends of changes with NF-κB mRNA expression were similar to immunohistochemistry. The expressions of NF-κB mRNA in experimental control group were highter than those of blank control group. There was significant difference(t=30.431,P < 0.05). The expressions of NF-κB mRNA in experimental group were lower than those of experimental control group. There was significant difference(t=18.464,P < 0.05).Conclusions: In diabetic rats, retinal was destroyed and arranged disorder. The number of retinal ganglion cells decreases and the retina of diabetic rats occurred morphological changes. Our study show the expression of TLR4 and NF-κB was increased significantly after diabetes. The expression of TLR4 and NF-κB was depressed significantly by OMT and the retina arranges disorder slightly. The number of retinal ganglion cells increases. It also showed OMT can reduce the structural damage of the retina. The depressed expression of NF-κB maybe is the mechanism of retina protective effect for OMT. TLR4 maybe was the mediator in the pathway.
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