title: Lonicerae Japonicae Flos attenuates diabetic retinopathy by inhibiting retinal angiogenesis.
abstract: BACKGROUND
  Lonicerae Japonicae Flos (Jin-Yin-Hua) is a well-known traditional Chinese medicine used for clearing away heat and toxic material.
  
  
  OBJECTIVE
  This study aims to observe the attenuation of aqueous extract of Lonicerae Japonicae Flos (FL) against streptozotocin (STZ)-induced diabetic retinopathy (DR) and its engaged mechanism.
  
  
  METHODS
  STZ-induced proliferative DR (PDR) for 5 month in C57BL/6 mice was used in this study. Retinal vessels were observed by immunofluorescence staining with cluster of differentiation 31 (CD31) and histopathological evaluation. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum vascular endothelial growth factor (VEGF) content. Cell proliferation was detected by 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide (MTT) assay in choroid-retinal endothelial RF/6A cells. VEGF-induced tube formation in RF/6A cells was observed. The contents of chlorogenic acid (CGA), caffeic acid (CA), and luteolin in FL were detected by high-performance liquid chromatography (HPLC).
  
  
  RESULTS
  Histopathological evaluation demonstrated that retinal vessels were increased in STZ-induced PDR mice, whereas FL decreased such increase. The results of CD31 staining also showed that FL decreased the increased number of retinal vessels in STZ-induced PDR mice. In addition, FL reduced the increased serum VEGF content in STZ-induced PDR mice. FL reduced VEGF-induced RF/6A cell proliferation in the concentration-dependent manner, but had no obvious effect on RF/6A cell viability without VEGF stimulation. VEGF-induced tube formation in RF/6A cells was inhibited by different concentrations of FL. CGA, CA and luteolin all inhibited VEGF-induced tube formation in RF/6A cells, and the lowest effective concentration of CGA and CA was both 0.625μM, but of luteolin was 5μM. Furthermore, the results of HPLC demonstrated that the amount of CGA was the highest in FL.
  
  
  CONCLUSIONS
  FL ameliorates STZ-induced PDR by inhibiting retinal angiogenesis. Phenolic acid CGA is the main compound contributing to the inhibition of FL on retinal angiogenesis.
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; College of Pharmacy, Xinjiang Medical University, Urumqi 830011, China.
authors.forename: Lingyu
authors.initials: L
authors.lastname: Zhou
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Zhang
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Zengyang
authors.initials: Z
authors.lastname: Yu
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Xiyu
authors.initials: X
authors.lastname: Mei
authors.affiliation: College of Pharmacy, Xinjiang Medical University, Urumqi 830011, China.
authors.forename: Palida
authors.initials: P
authors.lastname: Abulizi
authors.affiliation: The Shanghai Key Laboratory for Complex Prescription, The MOE Key Laboratory for Standardization of Chinese Medicines, and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. Electronic address: lichenyue1307@126.com.
authors.forename: Lili
authors.initials: L
authors.lastname: Ji
mesh_terms: D020533:Angiogenesis Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D002109:Caffeic Acids / Q000302:isolation & purification / Q000494:pharmacology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002726:Chlorogenic Acid / Q000302:isolation & purification / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D031239:Lonicera / Q000737:chemistry*; D047311:Luteolin / Q000302:isolation & purification / Q000494:pharmacology*; D008810:Mice, Inbred C57BL; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D015861:Retinal Neovascularization / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D012171:Retinal Vessels / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D015398:Signal Transduction / Q000187:drug effects; D013311:Streptozocin; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
chemical_list: D020533:Angiogenesis Inhibitors; D002109:Caffeic Acids; D010936:Plant Extracts; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D002726:Chlorogenic Acid; D013311:Streptozocin; D047311:Luteolin; C040048:caffeic acid
keywords: Angiogenesis; CGA; Diabetic retinopathy; Lonicerae Japonicae Flos; VEGF