| Objective:To evaluate the changes of choroidal thickness in diabetic patients with different stages of diabetic retinopathy (DR) and diabetic macular edema (DME) based on enhanced depth imaging technique, primary culture of retinal muller cell in vitro, and the correlation between diabetic retinopathy of different stages and PPARy polymorphism and its relevant factors.Methods:A total of120cases of normal volunteers aged25to85years old was collected and divided into thress groups according to age. Enhanced depth imaging optical coherence tomography examination was performed to measure choroidal thickness. Correlation between choroidal thickness and age was analysed.92patients with type2diabetes were included and divided into3groups:Group A (DR-/DME-):36patients (36eyes) without diabetic retinopathy or diabetic macular edema; Group B (NPDR+/DME-):47patients (47eyes) with non-proliferative diabetic retinopathy and no diabetic macular edema; Group C (PDR+/DME-):9patients (9eyes) with proliferative diabetic retinopathy and no diabetic macular edema. Choroidal thickness between group A, B, C and the normal population was compared using one-way ANOVA and LSD-t test. Another33patients with non-proliferative diabetic retinopathy and diabetic macular edema were included. Biochemical tests including fasting blood glucose (FBG),2h-postprandial plasma glucose (2h-PG), glycosylated hemoglobin (HbAlc), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL) were collected. The choroidal thickness in DME group and that of diabetic retinopathy in different stages were compared using one-way ANOVA analysis. The correlation between choroidal thickness and duration of diabetes, fasting blood glucose, HbAlc, LDL, TG, TC, HDL, SBP and DBP was analysed using Pearson correlation analysis. In addition,120eyes of120cases with diabetic retinopathy were collected and PPARy pro12Ala genotype was detected with direct sequencing. The genotype and allele frequency in diabetic retinopathy of different stages were compared. Correlation between allele frequency and genotype of PPARy polymorphism and different diabetic retinopathy was evaluated. Association of genotype of PPARy with TG, LDL, HDL, HbAlc, UAER was analysed. Primary culture of retinal muller cell of SD rat in vitro was done to provide a basis for further researchResult:Average SFCT in normal population was (271.32±35.63) μm. Mean SFCT in men was (286.32±35.98) μm, and (254.33±29.61) μm in women. Choroid was thicker in men than in women, and the differenc was significant (P<0.05). The SFCT decreases gradually according to age with negative correlation (r=-0.781, P<0.001). SFCT in group C ranged171to289μm, mean (232.98±34.13) μm, compared with normal controls, the difference was statistically significant (P<0.05). SFCT in group D ranged156to278μm, mean (229.64±33.66)μm, compared with normal controls of45to65years old, the difference was statistically significant (P<0.01). There was a significant difference of SFCT between group D and group B (P<0.01). Of all the variables, HbAlc, LDL and UAER showed a significantly high EXP(B) of5.512(P<0.001);2.821(P=0.017); and1.582(P=0.009), respectively. There was no statistically correlation between average SFCT and duration of diabetes, fasting blood glucose, HbAlc, TG, TC, HDL, Creatinine, SBP and DBP (r=-0.253,0.219,0.095,0.310,0.185,0.224,0.237,0.421,0.281, P>0.05), while a statistically correlation between SFCT and LDL and UAER was observed in our study (r=-0.601,-0.673, P<0.01). Short repeatedly digestion by trypsin, muller cells identified by glutamine synthetase as specific labeled antibodies showed same morphology with positive reaction of glutamine synthetase. Distribution of PPARy gene G allele frequency was5.8%, C/C was dominant genotype in DR, the proportion was87%and89.2%respectively, and the difference was not statistically significant. UAER levels were significantly lower in the G/G or G/C genotype compared with C/C in diabetic retinopathy, with a statistically significant difference, and the difference TG, LDL, HDL, HbAlc was not statistically significant.Conclusion:the average SFCT in normal people was (271.32±35.63)μm. SFCT was thicker in men. Choroid was thinest in the nasal to fovea. The SFCT decreases gradually according to age with negative correlation. The SFCT decreased with severity of diabetic retinopathy. The SFCT in PDR without DME was thinner than that of normal people or patients without diabetic retinopathy. Compared with patients with NPDR, SFCT in patients with DME was thinner significantly. HbAlc and LDL levels in patients with DME were negatively correlated with choroidal thickness. Repeated trypsin digestion is a reliable method of primary muller cell culture in vitro, which can obtain purified muller cell. No clear correlation between the distribution of genotypes and allele frequencies of pro12Ala and diabetic retinopathy of different stages. But PPARy gene G allele may reduce URER levels in patients with diabetic retinopathy and may have a protective effect on renal function. |
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