title: Melissa officinalis extract inhibits laser-induced choroidal neovascularization in a rat model.
abstract: OBJECTIVE
  This study investigated the effect of Melissa officinalis extract on laser-induced choroidal neovascularization (CNV) in a rat model. The mechanism by which M. officinalis extract acted was also investigated.
  
  
  METHODS
  Experimental CNV was induced by laser photocoagulation in Brown Norway rats. An active fraction of the Melissa leaf extract was orally administered (50 or 100 mg/kg/day) beginning 3 days before laser photocoagulation and ending 14 days after laser photocoagulation. Optical coherence tomography and fluorescein angiography were performed in vivo to evaluate the thickness and leakage of CNV. Choroidal flat mount and histological analysis were conducted to observe the CNV in vitro. Vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, and MMP-9 expression were measured in retinal and choroidal-scleral lysates 7 days after laser injury. Moreover, the effect of M. officinalis extract on tertiary-butylhydroperoxide (t-BH)-induced VEGF secretion and mRNA levels of VEGF, MMP-2, and MMP-9 were evaluated in human retinal epithelial cells (ARPE-19) as well as in human umbilical vein endothelial cells (HUVECs).
  
  
  RESULTS
  The CNV thickness in M. officinalis-treated rats was significantly lower than in vehicle-treated rats by histological analysis. The CNV thickness was 33.93±7.64 µm in the high-dose group (P<0.001), 44.09±12.01 µm in the low-dose group (P = 0.016), and 51.00±12.37 µm in the control group. The proportion of CNV lesions with clinically significant fluorescein leakage was 9.2% in rats treated with high-dose M. officinalis, which was significantly lower than in control rats (53.4%, P<0.001). The levels of VEGF, MMP-2, and MMP-9 were significantly lower in the high-dose group than in the control group. Meanwhile, M. officinalis extract suppressed t-BH-induced transcription of VEGF and MMP-9 in ARPE-19 cells and HUVECs.
  
  
  CONCLUSIONS
  Systemic administration of M. officinalis extract suppressed laser-induced CNV formation in rats. Inhibition of VEGF and MMP-9 via anti-oxidative activity may underlie this effect.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Eun Kyoung
authors.initials: EK
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Seoul National University Hospital Biomedical Research Institute, Seoul, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea.
authors.forename: Hyun Beom
authors.initials: HB
authors.lastname: Song
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyeong Gon
authors.initials: HG
authors.lastname: Yu
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D002460:Cell Line; D002829:Choroid / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D020256:Choroidal Neovascularization / Q000378:metabolism / Q000517:prevention & control*; D004353:Drug Evaluation, Preclinical; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D031334:Melissa / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D041623:Tomography, Optical Coherence; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D010936:Plant Extracts; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat