The Study Of The Relationship Between DNA Oxidative Damage Product—8-OHdG And The Occurrence Of Diabetic Retinopathy

Objection: Oxidative damage is one of the significant pathogenesis of diabetic retinopathy(DR),which plays an important role in the occurrence and development of diabetic retinopathy.The study and report about DNA oxidative damage's effect on diabetic retinopathy can not be found generally.Our study is aimed to analysis the difference of 8-OHdG in different stages of diabetic retinopathy by measuring the content of 8-hydroxydeoxyguanosine acid(8-OHdG)in the serum and urine of type 2 diabetic patients,which is the recognized biomarker of the oxidative damage in DNA.Then we want to find the sensibility of 8-OHdG in detecting the progress of diabetic retinopathy.Methods:We choosed 67 local patients with type 2 diabetes in the departments of ophtalmology and endocrinology in our hospital.They are divided into three groups according to the dilated-pupil retinal examination,retinal photography and fundus fluorescence angiography(FFA),they were: non-diabetic retinopathy group(DR0,n=22);nonproliferative diabetic retinopathy group(DR1,n=21);proliferative diabetic retinopathy group(DR2,n=24),and selected 17 healthy individuals from the Physical examination center in our hospital(ND).Every object's basic data was noted carefully,including gender,age,blood pressure,weight,height,the duration of diabetes,fasting blood-glucose(FBG)and Glycated hemoglobin(HbA1c).8-OHdG was measured by Enzyme-linked immunosorbent assay techno logy(ELISA).In addition,from the above objects,the diabetic patients without diabetic retinopathy in a duration beyond 10 years was named LD(n=8),the duration less than 10 years was named SD(n=14),the patients with diabetic retinopathy in a duration less than 10 years was named SRD(n=25).Results:1.The levels of 8-OHdG in serum and urine are both different between ND group,DR0 group,DR1 group,and DR2 group,and DR2>DR1>DR0>ND,they both have obvious significance(P<0.01).2.The results of comparision between two groups: 8-OHdG in serum: The difference has no significance between ND and DR0(P>0.05).Tt has significant difference between ND and DR1(P<0.05).There is significant difference between ND and DR2(P<0.01).It has no significance between DR0 and DR1(P=0.05).It has obvious significance between DR0 and DR2(P<0.01).There is no significance between DR1 and DR2(P>0.05).8-OHdG in urine: The difference has no significance between ND and DR0(P>0.05).It has obvious significant difference between ND and DR1(P<0.01).There is significant difference between ND and DR2(P<0.01).It has no significance between DR0 and DR1(P>0.05).It has significance between DR0 and DR2(P<0.05).There is no significance between DR1 and DR2(P>0.05).The 8-OHdG in serum has a significant positive correlation with the level in urine(r=0.745,P<0.01).3.The correlation analysis: Around the patients with type 2 diabetes,the 8-OHdG in serum have a positive variation to HbA1c(r=0.613,P<0.01),the result is similar as its' level in urine(r=0.528,P<0.01).There is no correlation between the 8-OHdG both in serum and urine with the duration of diabetes and FBG in the patients with diabetes.4.The levels of 8-OHdG in serum and urine both have significant difference between LD group,SD group and SDR group(SDR>SD>LD,in serum,P=0.012,in urine,P=0.028).SDR compared with SD and LD,the differences in serum and in urine are both significant(P<0.05).SD compared with SD and LD,the differences in serum and in urine are both significant(P<0.05).Conclusion: 1.With the development of DR,The level of 8-OHdG appears an increasing trend,and it is obviously elevated in PDR.2.Serum is more appropriate for detection,The level of 8-OHdG in serum and urine is obviously related to HbA1 c.3.The antioxidant ability is stronger,the morbidity of DR is lower.