Effects Of Purendan On Retinal Nerve Injury And Related Factors In Diabetic Rats

Objective:To investigate the effect of PRD on retinal nerve injury and related factors in diabetes rats.Methods:The rat model of type 2 diabetes mellitus was established by high-fat and high-sugar diet combined with low-dose streptozotocin（STZ）single intravenous injection.The successful rats were randomly divided into two groups:PRD treatment group with 12 rats and diabetes model group with 12rats,and the other 12 healthy rats of the same age were taken as normal control group.After the model was established,the rats in PRD treatment group were given PRD 1.8g·kg^-1·d^-1by gavage for 8 weeks.After drug intervention,the morphological changes of rat retina were observed by HE method,the relative expression levels of PI3K and Akt m RNA in rat retina were detected by RT-q CPR method,the relative expression levels of p-PI3K,p-Akt and Caspase-12 protein in rat retina were detected by immunohistochemistry method,and the apoptosis index of retinal nerve cells was calculated by TUNEL method.Results:1.Microscopic observation showed that all layers of retina in normal control group had complete structure,orderly arrangement,clear boundary,smooth and complete internal limiting membrane,regular distribution of retinal cells and normal morphology.In the diabetic group,the retinal structure of each layer was disordered,the boundary was blurred,the internal limiting membrane was rough and broken,and the retinal ganglion cells were vacuolated and decreased in number.Compared with DM group,the cells in each layer of retina in PRD treatment group are relatively orderly arranged,with relatively complete structure,relatively clear boundary,relatively smooth internal limiting membrane and relatively light vacuolation and reduction of ganglion cells.2.The relative expressions of PI3K and Akt m RNA in the retina of rats in PRD treatment group were（0.96±0.22 and 90.10±17.84）,respectively,which were significantly higher than those in diabetic model group（0.57±0.16 and 48.99±14.22）,and the difference were statistically significant（both P<0.05）.3.The relative expressions of p-PI3K and p-Akt protein in the retina of rats in PRD treatment group were（0.478±0.057 and 0.485±0.091）,respectively,which were significantly higher than those in diabetic model group（0.360±0.041 and 0.330±0.019）,and the difference were statistically significant（both P<0.05）;the relative expression of Caspase-12 protien in the retina of rats in PRD treatment group was0.418±0.057,respectively,which was significantly lower than this in diabetic model group0.554±0.116,and the difference was statistically significant（P<0.05）.4.The apoptosis index of retinal nerve cells in PRD treatment group was（0.03575±0.00538）,which was significantly lower than that in diabetic model group（0.066550±0.00533）,and the difference was statistically significant（P<0.05）.Conclusion:PRD can up-regulate the expression of p-PI3K and p-AKT in retina,down-regulate the expression of Caspase-12,activate PI3K/Akt signaling pathway,inhibit ERS-specific Caspase-12 apoptosis pathway,so as to improve the apoptosis of retinal nerve cells,and play a protective role in diabetic retinal nerve injury.