Erfassung der Angiogenese bei Antigen-induzierter Arthritis der Maus mittels Intravitalfluoreszenzmikroskopie

Abstract

The inhibition of angiogenesis might be a therapeutic approach to prevent joint destruction caused by the overgrowing synovial tissue during chronic inflammation. The aim of this study was to investigate angiogenesis in the knee joint of mice with antigen-induced arthritis (AiA) by means of intravital microscopy. Material and Methods: Intravital microscopic assessment was performed in 14 female mice (C57BL6/129SV) on day 8 after AiA induction in two groups (controls, animals with AiA). After preparation of the knee joint under inhalation anesthesia, synovial tissue was investigated by fluorescence microscopy using the plasma marker FITC-dextran (150 kDa). Quantitative assessment of vessel density was performed according to the following categories: “functional capillary density” (FCD, vessels < 10 µm in diameter),“functional vessel density” (FVD, vessels ≥ 10 µm) and FVD of “vessels with angiogenic criteria” (at least one of the following: convoluted vessel, abrupt changes in diameter, unphysiologic branching). After immunostaining of tissue sections with a monoclonal antibody against von Willebrand factor, vessel density (stained endothelium) was quantified as microvessel count/area. Results: There was no significant difference in FCD between the control group (337±9 cm/cm2; mean±SEM) and the AiA group (359±13). However, the density of vessels ≥10 µm in diameter was significantly increased in animals with AiA (135±10 cm/cm2 vs. 61±5 control). Furthermore, the density of blood vessels “with angiogenic criteria” was enhanced in arthritic animals (79±17 cm/cm2 vs. 12±2 control). In addition, there was a significant increase in the “microvessel count” in arthritic animals (297±25 mm-2 vs. 133±16 control). Conclusion: These findings demonstrate that angiogenesis in murine AiA can be assessed quantitatively using intravital microscopy. Further studies will address antiangiogenic strategies in AiA.