Effects of inhibiting NgR on retinal ganglion cells density and synaptophysin expression of diabetic rats / 眼科新进展

ABSTRACT

Objective To investigate the effects of inhibiting NgR on retinal ganglion cells density and synaptophysin expression of diabetic rat.Methods Thirty-two SD male rats were randomly divided into normal control group,diabetic group,siNgR group and scNgR group,8 rats in each group.Normal control group was given no any treatment.Diabetes model was induced by intraperitoneal injection of 50 mg · kg-1 streptozotocin in diabetic group,siNgR group and scNgR group,and the blood giucose more than 16.7 mmol · L-1 at 72 hours was set as the successfully model.The rats of siNgR group were intravitreally administrated with anti-NgR nucleotide and the rats of scNgR group intravitreally administrated with negative nucleotide.Eight weeks later,HE staining was conducted to detect density of retinal ganglion cell (RGC),immunofluorescence was used to evaluate the expression and distribution of synaptophysin (a marker of synaptic number).Relative expression of NgR and synaptophysin in retina were analyzed by Western blot.Results RGC density in normal control group,diabetes group,siNgR group and scNgR group were (624.33 ± 3.51) mm-2,(420.00 ± 2.65) mm-2,(621.67 ± 1.53) mm-2,(416.67 ± 2.52) mm-2,respectively.There was significant difference among four groups (F =5985.37,P ＜ 0.01).Compared with normal control group,RGC density in diabetes group and scNgR group were obviously decreased (all P ＜0.01),but siNgR group had no obviously change (P ＞ 0.05).The synaptophysin mainly expressed in the inner and outer network layer.Compared with normal control group,the positive expression of synaptophysin in diabetes group and scNgR group were decreased,but siNgR group had no obviously change.The relative expression of NgR in normal control group,diabetes group,siNgR group and scNgR group were (11.26 ±0.02) ％,(19.38 ± 0.10) ％,(11.17 ± 0.02) ％,(19.47 ± 0.31) ％,respectively.There was significant difference among four groups (F =2466.09,P ＜ 0.01).Compared with normal control group,the relative expression of NgR in diabetes group and scNgR group were obviously decreased (all P ＜ 0.01),but siNgR group had no obviously change (P ＞0.05).The relative expression of synaptophysin in normal control group,diabetes group,siNgR group and scNgR group were (35.76 ± 0.15) ％,(25.47 ± 0.36) ％,(35.28 ± 0.12) ％,(25.03 ± 0.75) ％,respectively.There was significant difference among four groups (F =583.70,P ＜ 0.01).Compared with the normal control group,the expression of synaptophysin in diabetic group and scNgR group were decreased increased (all P ＜ 0.01),while there was no significant difference in siNgR group (P ＞ 0.05).Conclusion Inhibiting the expression of NgR in the retina of diabetic rats can help to restore the number of synapses and protect the damaged RGC.