Macrophage depletion inhibits experimental choroidal neovascularization

Invest Ophthalmol Vis Sci. 2003 Aug;44(8):3578-85. doi: 10.1167/iovs.03-0097.


Objective: To investigate the role of macrophages in the development of laser-induced choroidal neovascularization (CNV) by selective depletion with liposomal clodronate (Cl(2)MDP-LIP).

Methods: Laser photocoagulation was used to induce CNV in wild-type C57BL/6J mice. Animals were treated with intravenous (IV) and/or subconjunctival (SC) Cl(2)MDP-LIP or PBS-LIP at the following time points: 2 days before, immediately after, 2 days before and immediately after, or 2 days after laser injury. CNV responses were compared on the basis of en masse volumetric measurements and fluorescein angiography after laser photocoagulation. Macrophages were identified by immunostaining for F4/80, and vascular endothelial growth factor (VEGF) expression was quantified by ELISA.

Results: Macrophages invaded the site of laser injury within 1 day of photocoagulation and peaked at 3 days. IV Cl(2)MDP-LIP significantly decreased the volume of CNV and angiographic leakage when administered 2 days before and/or immediately after laser injury, but not when administered 2 days after injury. SC Cl(2)MDP-LIP significantly decreased lesion volume when coadministered with IV PBS-LIP but not IV Cl(2)MDP-LIP. IV Cl(2)MDP-LIP was significantly more beneficial when administered 2 days before laser injury than immediately after, but combining SC Cl(2)MDP-LIP with IV treatment eliminated this difference. Reduction in CNV volume correlated with VEGF protein levels and number of infiltrating macrophages.

Conclusions: Generalized macrophage depletion reduced the size and leakage of laser-induced CNV and was associated with decreased macrophage infiltration and VEGF protein. These findings define the role of the macrophage as a critical component in initiating the laser-induced CNV response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Differentiation / metabolism
  • Antimetabolites / administration & dosage
  • Cell Movement / physiology
  • Choroidal Neovascularization / physiopathology*
  • Choroidal Neovascularization / prevention & control
  • Clodronic Acid / administration & dosage
  • Disease Models, Animal
  • Endothelial Growth Factors / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Fluorescein Angiography
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Liposomes
  • Lymphokines / metabolism
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Macrophages / physiology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors


  • Antigens, Differentiation
  • Antimetabolites
  • Endothelial Growth Factors
  • Intercellular Signaling Peptides and Proteins
  • Liposomes
  • Lymphokines
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors
  • monocyte-macrophage differentiation antigen
  • Clodronic Acid