Dyslipidemia plays an important role in the pathogenesis of diabetic retinopathy (DR).Apreliminary study found that low-density lipoprotein cholesterol, apolipoprotein (Apo)Band ApoB/ Apo A1 ratio were positively correlated with DR, while high-density lipoprotein cholesterol, Apo A1 was negatively correlated with DR and proliferative DR. Reducing the blood fats to be helpful to DR control. However, the mechanism of hyperlipidemia in the pathogenesis of DR, the reason of dyslipidemia in diabetic patients and the interaction between hyperglycemia and hyperlipidemia in DR are not clear yet. Moreover, there is no predictive indicators related to blood lipid for DR. Understanding the relationship between dyslipidemia and DR can provide definite evidence for fat-reducing therapy for DR control.
Objective To investigate if insulin can affect the expression of vascular endothelial growth factor (VEGF) in the retina of streptozotocin-induced diabetic rats. Methods A total of 60 male SpragueDawley rats were randomly divided into sodium citrate buffer control group (CIT-CON, n=30) and STZ-induced diabetic group (STZ-DM, n=30). At the 16th week, 24 rats from CIT-CON group at random were randomly divided to group A (sodium citrate buffer control group, n=12) and group B (sodium citrate buffer plus insulin group, n=12). The remaining 6 rats from as CIT-CON group served as negative control. At the same time, 24 rats from STZDM group at random were randomly divided to group C (STZinduced diabetic group, n=12) and group D (STZ-induced diabetic plus insulin group, n=12). The remaining 6 rats from STZ-DM group also served as negative control. 4 IU of insulin was injected subcutaneously to rats of group B and D. Immunohistochemistry, Western blot and Real-time polymerase chain reaction (RT-PCR) were used to measure the expression level of VEGF protein and mRNA respectively. RESULTS Insulin significantly increased the VEGF mRNA (7.71plusmn;0.25 vs 5.36plusmn;0.37, t test Plt;0.05) and protein expression (0.4925plusmn;0.0122 vs 0.4272plusmn;0.0110, t test Plt;0.05) in the retina of CITCON rats. However, in retina of STZDM rats, insulin had no effect on VEGF mRNA (8.92plusmn;0.27 vs 9.05plusmn;0.28, t test, Pgt;0.05) and protein expression (0.5152plusmn;0.0109 vs 0.5099plusmn;0.0100, t test Pgt;0.05). Conclusions Insulin had no effect on VEGF expression in the retina of STZ-DM rats.
The pathogenesis of diabetic retinopathy (DR) is more complex. For the upstream of traditional pathogenesis, to looking for unifying mechanism theory which proposed in foundation of common promoters and the latest view of DR may be the result of chronic inflammation. Both of them provide the basic and clinical theraby of DR with new direction. Therefore, there are many related issues still needs to intensive study. （Chin J Ocul Fundus Dis，2008，24：237-239）
Objective To determine the association of -429T/C and G1704T polymorphisms in the receptor for advanced glycation end products gene with proliferative diabetic retinopathy (PDR). Methods Case-control study. From the Beijing Desheng Diabetic Eye Study cohort of 1467 patients with type 2 diabetes mellitus (T2DM),atotal of 97 patients with PDR and 105 diabetic patients without retinopathy (DWR, duration of diabetes 15 years) were included for this study. Questionnaires were collected and general ophthalmologic examinations were performed. Biochemical analysis was conducted. DNA was extracted from peripheral venous blood. The -429T/C and G1704T single nucleotide polymorphisms were detected by the means of PCR-restrication fragment length polymorphisms. Results The frequency distribution of -429T/C in DWR group was 81.0% in TT, 16.1% in TC, 2.9% in CC. The frequency distribution of -429T/C in PDR group was 77.3% in TT, 20.6% in TC, 2.1% in CC. There was no significant statistical difference between the two groups (χ2=0.40, P > 0.05). Frequency of the -429T/C minor alleleCin the DWR and PDR group were 11.0% and 12.4%, respectively, with no significant statistical difference between the two groups (χ2=0.20，P > 0.05). The frequency distribution of G1704T in DWR group was 66.7% in GG, 29.5% in GT, 3.8% in TT. The frequency distribution of G1704T in PDR group was 78.4% in GG, 21.6% in GT. There was no significant statistical difference between the two groups (χ2=3.44, P > 0.05). Frequency of the G1704T minor alleleTin the DWR and PDR group were 18.6% and 10.8%, respectively, in which significant difference was found within the two groups (χ2=4.79, OR=1.88，95%CI: 1.06 - 3.33, P > 0.05). Conclusions G1704T polymorphism is associated with PDR presence and 1704G allele may increase the risk of PDR.
Objective To observe the expression of N-cadherin in streptozotocin (STZ)-induced diabetic Sprague-Dawley (SD) ratsprime;retinae. Methods Celiac injection with 65 mg/kg STZ was performed on 20 rats to set up the diabetic model, and celiac injection with the same volume citrate buffer was performed on other 20 SD rats as the control. Vascular permeability was detected by Evans blue method. The expression of N-cadherin in both normal and STZ-induced diabetic ratsprime;retinae and trypsinase-digested retinal microvessels were detected by immunohistochemistry method and Western blotting analysis. Results Retinal vascular permeability increased 68%, 91% and 125% 4, 8, and 12 weeks, respectively, after diabetic models was induced (Plt;0.005). In the control group, the expression of N-cadherin was detected in the outer and inner plexiform layer, inner nuclear layer，ganglion cell layer,internal limiting membrane and between retinal endothelial cells and pericytes. However, the expression of N-cadherin significantly decreased in STZ-induced diabetic rats retinae at the 12th week. The results of Western blotting analysis showed that the expression of N-cadherin obviously decreased as the diabetic retinopathy developed. Conclusion The decrease of expression of Ncadherin in the retinae of STZ-induced diabetic rats suggests that N-cadherin may participate in the development of diabetic retinopathy at the early stage. (Chin J Ocul Fundus Dis,2007,23:269-272)
ObjectiveTo investigate the expression and mechanism of miR-1470 in plasma of diabetic retinopathy (DR) patients.MethodsThirty patients with DR (DR group), 30 patients with diabetes (DM group) and 30 normal healthy subjects (normal group) were enrolled in the study. Three groups of subjects were taken 5 ml of venous blood, and total plasma RNA was extracted and purified. The differentially expressed miRNAs in the plasma of DR patients were screened by gene chip, and the results of gene chip detection were verified by reverse transcription polymerase chain reaction (RT-PCR). Bioinformatics was used to predict potential target genes for miRNA regulation, and miR-1470 and its target gene epidermal growth factor receptor (EGFR) were screened. Human retinal microvascular endothelial cells (hREC) were divided into normal group (sugar concentration 5.5 mmol/L) and high glucose group (sugar concentration 25.0 mmol/L). hREC was transfected into miR-1470 mimics to establish a miR-1470 high expression cell model, which was divided into blank control group, high expression group and negative control group. The expression of miR-1470 was detected by RT-PCR. The expression of EGFR protein was detected by Western blot. The measurement data of the two groups were compared using the independent sample t test. The comparison of the measurement data between the two groups was analyzed by ANOVA. The comparison between the measurement data of the groups was compared by multiple comparisons.ResultsThe results of RT-PCR were consistent with those of the gene chip. The expression of miR-1470 in the plasma of the DR group, the DM group and the normal group was statistically significant (F=63.486, P=0.049). Compared with the DM group and the normal group, the expression of miR-1470 in the DR group was significantly decreased, and the difference was statistically significant (q=111.2, 73.9; P＜0.05). The expression of miR-1470 in hREC in the high glucose group was significantly lower than that in the normal group (t=42.082, P=0.015). The expression of EGFR protein in hREC of high glucose group was significantly higher than that of normal group (t=−39.939, P=0.016). The expression of miR-1470 (F=637.069, P=0.000) and EGFR (F=122.908, P=0.000) protein expression in hREC of blank control group, negative control group and high expression group were statistically significant . Compared with the blank control group and the negative control group, the expression of miR-1470 in hREC of high expression group was significantly increased (q=329.7, 328.8; P＜0.05), and the expression of EGFR protein was significantly decreased (q=242.5, 234.6; P＜0.05). There was no significant difference in the expression of miR-1470 and EGFR protein in hREC between the negative control group and the blank control group (q=1.5, 7.9; P＞0.05).ConclusionThe expression of miR-1470 in the plasma of patients with DR is significantly down-regulated, and the increase of EGFR expression may be related to it.