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Objective To investigate the expression and clinical significance of miR-126 and vascular endothelial growth factor (VEGF) in proliferative diabetic retinopathy (PDR).Methods 226 cases of diabetic retinopathy (DR) patients admitted in our hospital were studied,including 110 cases of PDR (group PDR),116 non proliferative diabetic retinopathy (NPDR) (group NPDR).80 patients with diabetes mellitus without retinopathy (NDR) were enrolled in DR group at the same period,another 80 healthy subjects (control group) were selected as control group.The plasma miR-126 level of all subjects was detected by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR).The enzyme linked immunosorbent assay (ELISA) method was used to detect plasma VEGF level.The clinical diagnostic value of miR-126 and VEGF in PDR patients was further analyzed.Results Plasma levels of miR-126 in PDR group,NPDR group and NDR group were lower than those in control group (P ＜ 0.05),PDR group was lower than NPDR group and NDR group (P ＜ 0.05);plasma levels of VEGF in PDR group,NPDR group and NDR group were higher than those in control group (P ＜ 0.05),PDR group was higher than NPDR group and NDR group (P ＜ 0.05).Total cholesterol (TC),triglyceride (TG) and glycated hemoglobin (HbAlc) in PDR group were higher than those in NPDR group and NDR group (P ＜0.05),low density lipoprotein cholesterol (LDL-C) in PDR group,NPDR group and NDR group were higher than those in control group (P ＜ 0.05),and LDL-C in PDR group was higher than that in NPDR group and NDR group (P ＜0.05).High density lipoprotein cholesterol (HDL-C) in PDR group and NDR group was lower than that in control group (P ＜ 0.05),C-reactive protein (CRP) in PDR group,NPDR group and NDR group was higher than that in control group (P ＜ 0.05);plasma miR-126 levels in PDR group were negatively correlated with TC,LDL-C,CRP and HbA1c (P ＜ 0.05),but positively correlated with HDL-C (P ＜ 0.05),and no correlation with TG;the plasma levels of VEGF in PDR patients were positively correlated with TC,TG,LDL-C,CRP and HbAlc (P ＜0.05),but negatively correlated with the expressions of miR126 (r =-0.573,P =0.000);the AUC of miR-126 was 0.861,and when the cut-off value was ＜0.64,the diagnostic sensitivity and specificity were 82.50％,83.64％;the area under curve (AUC) of VEGF was 0.889,and when the cut-off value was ＜ 7.000,the sensitivity and specificity of diagnosis were 82.73％,86.25％;0.847 for the AUC of HbA1c,and the sensitivity and specificity 81.82％,87.50％ respectively.Conclusions Plasma miR-126 is low-expressed and VEGF is high-expressed in PDR patients,there is a negative correlation between the two indexes.They may be involved in the course of PDR through abnormal lipid metabolism and inflammatory reaction and may be a potential biomarker for early diagnosis of PDR.
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BACKGROUND: Soil organic carbon (SOC) sequestration, methane emission, and the net carbon sink represented by rice straw incorporated into soil (RIS) were studied using long-term experimentation with rice straw incorporated into soil (LRIS) and short-term experimentation with different patterns of rice straw incorporated into soil (SPRIS). RESULTS: Soil organic carbon could be improved by RIS combined with soil ploughing. The increased rate of SOC deposition per cultivated layer was 0.10 t C ha(-1) for 2.625 t ha(-1) straw incorporated each season in LRIS and 0.36 t C ha(-1) for 4.5 t straw ha(-1) season(-1) incorporated in SPRIS; the apparent SOC conversion by rice straw (stubble) was reduced as the amount of incorporated straw increased. However, RIS methane emission from paddy fields also significantly exacerbated the CH(4) emission flux observed during the early and late rice growing seasons, which was increased by 75.0% (P < 0.01) and 251.5% (P < 0.01), respectively, compared with combined application of nitrogen, phosphorus and potassium fertiliser (NPK). The apparent methane conversion of straw was almost uniform with a similar rice yield and soil cultivating mode. Among the patterns of RIS, methane emission was significantly reduced under straw covering untilled land, and this property led to the lowest apparent methane conversion. CONCLUSION: RIS with ploughing and tilling resulted in negative carbon sequestration because of increased methane emissions. A combined NPK application with only rice stubble incorporation may be sustainable for a higher rice yield, but this approach has a reduced rate of negative carbon sequestration in the paddy field. Straw covering with no tillage was the best measure to realise high yield and low carbon emission for RIS.
