title: Macrophages promote vasculogenesis of retinal neovascularization in an oxygen-induced retinopathy model in mice.
abstract: To investigate the role of macrophages in oxygen-induced retinal neovascularization (NV) in mice, particularly the involvement of bone marrow-derived cells (BMCs) and the underlying mechanisms, BMCs from green fluorescent protein (GFP) transgenic mice were transplanted into postnatal day (P) 1 mice after irradiation. The mice were exposed to 75 % oxygen from P7 to P12 to initiate oxygen-induced retinopathy (OIR). The macrophages were depleted by injection of clodronate-liposomes (lip) intraperitoneally. The eyes were collected at P12 and P17. Retinal flatmounts and histopathological cross-sections were performed to analyze the severity of retinal NV and BMC recruitment. BMCs immunopositive for CD31 (PECAM-1; endothelial cell marker) and α-SMA (smooth muscle cell marker) antigens were detected using a confocal microscope. Expression of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) mRNA was detected by RT-PCR. The VEGF, SDF-1, CXCR4 and CD45 protein expression was detected by western blot examination. The retinal avascular area in OIR mice at P12 was unaffected after macrophage depletion carried out twice (38.27 ± 1.92 % reduction) using clodronate-lip. The retinal avascular area and the NV area at P17 were reduced after macrophage depletion four times (79.53 ± 1.02 % reduction); these findings were supported by retinal flatmounts and histopathological cross-sections. Macrophage depletion led to significant inhibition of BMC recruitment into the NV tufts at P17, with decreased expression of retinal VEGF, SDF-1, CXCR4 and CD45. The recruited BMCs differentiated primarily into CD31-positive endothelial cells (ECs) and α-SMA-positive smooth muscle cells (SMCs). This study suggested that macrophages promoted the vasculogenesis of retinal NV, particularly the contribution of BMCs in the mouse OIR model, which might be triggered by VEGF and SDF-1 production.
authors: Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, No.15 West Changle Road, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Xiang
authors: X
authors: Gao
authors: Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, No.15 West Changle Road, 710032, Xi'an, Shaanxi, People's Republic of China. wangys003@126.com.
authors: Yu-Sheng
authors: YS
authors: Wang
authors: Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, No.15 West Changle Road, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Xiao-Qin
authors: XQ
authors: Li
authors: Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, No.15 West Changle Road, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Hui-Yuan
authors: HY
authors: Hou
authors: Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, No.15 West Changle Road, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Jing-Bo
authors: JB
authors: Su
authors: State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Li-Bo
authors: LB
authors: Yao
authors: State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, 710032, Xi'an, Shaanxi, People's Republic of China.
authors: Jian
authors: J
authors: Zhang
mesh_terms: D061605:Administration, Intravenous; D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells / Q000473:pathology; D002454:Cell Differentiation; D002465:Cell Movement; D004195:Disease Models, Animal; D008264:Macrophages / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D010100:Oxygen; D012160:Retina / Q000473:pathology; D015861:Retinal Neovascularization / Q000150:complications / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000150:complications / Q000473:pathology*
chemical_list: D010100:Oxygen
keywords: Bone marrow-derived cells; Macrophages; Oxygen-induced retinopathy; Retinal neovascularization; Stromal cell-derived factor-1; Vascular endothelial growth factor