ObjectiveTo investigate the relationships between the promoter methylation status of connective tissue growth factor (CTGF) gene and diabetic retinopathy, and its effects on the serum levels of CTGF.

MethodsOne hundred and twenty hospitalized diabetic patients in endocrinology department in addition select 58 normal examined subjects in physical examination center from the Affiliated Zhongshan Hospital of Dalian University were investigated.According to the international clinical classification standards of diabetic retinopathy (2002), the diabetic retinopathy in all cases were identified using the fundus examination or fluorescein angiography.The subjects were divided into the diabetic retinopathy group (DR group, n=57), diabetes without retinopathy group (NDR group, n=63), and normal control group (NC group, n=58).The DNA was extracted from the peripheral white blood cells, the promoter methylation status of CTGF gene was detected using the methylation-specific PCR (MSP), and the serum levels of CTGF in three groups were analyzed using ELISA.

ResultsThe results of statistic analysis of the MSP showed that the CTGF gene promoter methylation rate in DR group was 24.45%, which was lower than that in NDR group (42.86%) and NC group (78.95%) (P < 0.05 and P < 0.01).The serum level of CTGF in DR group was signifcantly higher than that in NDR group and NC group (P < 0.01).

ConclusionsIn term of epigenetics, the promoter hypomethylation status of CTGF gene can lead to the increasing of serum level of CTGF, which may be one of the mechanisms in the occurrence and development of the diabetic retinopathy.