Preliminary discussion on the potential mechanism of follistatin-like protein 1 in the process of proliferative diabetic retinopathy / 中华眼底病杂志

ABSTRACT

Objective:To observe the changes of follistatin-like protein 1 (FSTL1) in serum of patients with proliferative diabetic retinopathy (PDR).Methods:Twenty PDR patients confirmed by clinical examination and 20 normal people were included in the study. Human retinal vascular endothelial cells (HRCEC) were divided into HRCEC blank control group, 3 h hypoxia group, 6 h hypoxia group. Human umbilical vein endothelial cell (HUVEC) were divided into HUVEC blank control group, 3h hypoxia group, 6h hypoxia group. Real-time quantitative PCR (RT-PCR) and ELISA were used to determine the expression of FSTL1, TGF-β, VEGF, connective tissue growth factor (CTGF) mRNA and protein in peripheral blood and cells of all groups from all subjects.Results:The expressions of FSTL1, TGF-β1, CTGF, VEGF mRNA in blood samples of patients with PDR were 1.79±0.58, 0.97±0.21, 1.85±0.69 and 1.38±0.44. The expressions of FSTL1, TGF-β1 protein were 1.19±0.50, 0.71±0.24 ng/ml and 734.03±116.45, 649.36±44.23 ng/L. Compared with normal people, the differences were statistically significant ( tmRNA=0.90, 0.21, 2.85, 1.77; P=0.00, 0.00, 0.04, 0.02. tprotein=1.88, 7.68; P=0.00, 0.02). The cell viability of HRCEC cells in the 3 h hypoxia group and the 6 h hypoxia group were 0.66±0.05 and 0.64±0.04, respectively. Compared with the blank control group, the difference was statistically significant ( F=13.02, P=0.00). The cell viability of HUVEC cells in the 3 h hypoxia group and the 6 h hypoxia group were 0.63±0.06 and 0.68±0.06, respectively. Compared with the blank control group, the difference was statistically significant ( F=26.52, P=0.00). Comparison of FSTL1, TGF-β1, CTGF, and VEGF mRNA expression in HRCEC blank control group and 3 h hypoxia group, the differences were statistically significant ( F=14.75, 44.93, 85.54, 6.23; P=0.01, 0.00, 0.00, 0.03). Compared with the HRCEC blank control and 3 h hypoxia group, the expressions of FSTL1 and TGF-β1 protein were statistically significant ( P<0.05). There was a statistically significant difference in TGF-β1 protein expression in the hypoxic 6 h group ( P=0.03) and no significant difference in FSTL1 protein expression ( P=0.68). Comparison of FSTL1, TGF-β1, CTGF, and VEGF mRNA expression in HUVEC blank control group and 3h hypoxia group, the differences were statistically significant ( F=19.08, 25.12, 22.89, 13.07; P=0.00, 0.00, 0.00, 0.01). Immunofluorescence staining results showed that FSTL1, TGF-β1, CTGF, and VEGF proteins were positively expressed in cells in the 3h hypoxia and 6h hypoxia groups. Conclusion:The expression of FSTL1 gene and protein in serum of PDR patients was significantly higher than that of normal people.