Comparison of the neovascular effects of stimulated macrophages and neutrophils in autologous rabbit corneas

Abstract

The ability of peritoneal exudate macrophages and neutrophils to induce neovascularization was tested in autologous rabbit corneas. Macrophages and neutrophils elicited by proteose peptone or glycogen and macrophages activated by C parvum were purified, pelleted, and implanted 1-2 mm from the corneal limbus. Neovascular responses were evaluated by daily slit-lamp observations and terminal whole-mount and histologic examinations of colloidal carbon-perfused vessels. Pellets of elicited macrophages (5 X 10(5) - 6 X 10(6) cells, 92-98% macrophages) or activated macrophages (2 X 10(6) cells, 87-97% macrophages) induced neovascularization by 4 days in 72-82% of cases. In contrast, pellets of neutrophils (1 X 10(5) - 8 X 10(6) cells, 92-98% neutrophils) did not induce neovascularization in any case. Histologic examinations at 4-24 hours revealed diapedesis and substantial infiltration of peripheral blood neutrophils in response to implants of either macrophages or neutrophils. Infiltration was diminished by 48 hours and negligible at later times. The finding that neovascular responses were not evoked by implantation of neutrophils or by the accompanying infiltration of neutrophils indicates that neutrophils do not initiate neovascularization in this model. Under similar test conditions, neovascular responses were initiated by implantation of either elicited or activated macrophages.