Effects Of Purendan On The Expression Of S100A8 And S100A9 In Retina Of Diabetic Rats

Objective:To investigate the effect of PRD on the expression of S100A8 and S100A9 in retinal tissue of diabetic rats.Methods:Using high fat and sugar diet fed rats,low doses of chain urea with cephalosporins was produced by intraperitoneal injection of（STZ Streptozotocin）in type 2 diabetic rats model.The rats were randomly divided into diabetes model group and PRD treatment group with 12 rats in each group,and 12 rats of the same week age were taken as the control group.After modeling,the rats in the treatment group were intragastric administration of Purendan decoction at a dose of(1.8g·kg^-1·d^-1)for 8 w,and the other two groups were intragastric administration of equal volume of distilled water.Real-time fluorescence quantitative method（RT-q PCR）and immunohistochemical（IHC）staining were used to observe the relative expression levels of S100A8 and S100A9m RNA and protein in retinal tissue,and HE staining was used to observe the morphological structure of rat retina.Results:1.In the normal group,the retinal cells were densely arranged,with clear structure,smooth inner boundary membrane,regular arrangement of each layer,and clear boundary between the inner and outer nuclear layers;In model group,retinal cells were not densely arranged,the inner boundary membrane was not smooth and rough,ganglion cells were sparse and swollen,all retinal layers were poorly arranged and disordered,and the thickness was thinner than that in normal group,and more new capillaries could be seen in the outer plexus layer.The structure of inner core layer and outer core layer is disordered and the boundary is blurred.Compared with model group,PRD group had dense cell arrangement,smooth inner boundary membrane,thicker retina,regular arrangement of retinal layers,and clear boundary between inner and outer nuclear layers.2.S100A8 and S100A9 were expressed in the retinas of rats in the normal,model and PRD-treated groups.Positive expression appeared as brownish-yellow granular material on sections,mainly in the cytoplasm and cell membrane of the ganglion cell layer of the rat retina;in addition,small amounts of expression were also present in the inner and outer plexiform layers and the inner and outer nuclear layers of the retina.The mean optical density values of S100A8 in the normal group were0.153 7±0.00 3,0.225 9±0.002 7 in the model group and 0.162 9±0.00 3 in the PRD group,the mean optical density values of S100A9 in the normal group were 0.148 0±0.011 2,0.238 7±0.003 9 in the model group and 0.1647±0.00 2 in the PRD group.The mean optical density values of S100A8 and S100A9 in the retinas of rats in the model group were 0.148 0±0.011 2 and0.238 7±0.003 9 in the model group;the mean optical density values in the PRD group were 0.164 7±0.00 2.The mean optical density values of S100A8and S100A9 in the retinas of rats in the model group were significantly higher than those in the normal group at P<0.05;the mean optical density values of S100A9 in the PRD group were significantly higher than those in the treatment group at P<0.05.The protein expression levels of S100A8 and S100A9 in the retinas of the model group were higher than those of the normal group and were strongly positive,and the positive expression was significantly weakened after PRD treatment.3.Compared with normal group,the relative expression level of S100A8m RNA in retina of rats in model group was significantly increased（P<0.05）,indicating statistical significance;Compared with model group,the m RNA expression level of S100A8 in PRD group was significantly decreased,（P<0.05）,and the relative expression level of S100A9 m RNA showed the same trend as that of S100A8.Conclusion:PRD may reduce the microinflammatory damage of DR By decreasing the expression of S100A8 and S100A9 in the retina of diabetic rats.