Louisiana State University Health Sciences Center, Department of Ophthalmology and The Neuroscience Center of Excellence, 2020 Gravier Street, New Orleans, LA 70112, USA.
Exp Eye Res. 2012 Oct;103:9-16. doi: 10.1016/j.exer.2012.07.008. Epub 2012 Jul 22.
Platelet-activating factor (PAF) is a bioactive lipid mediator with strong inflammatory properties. PAF induces the expression and activation of metalloproteinase-9 (MMP-9) in corneal epithelial cells and myofibroblasts, and delays epithelial wound healing in an organ culture system. Lipoxin A(4) (LXA(4)) is a lipid mediator involved in resolution of inflammation and cornea epithelial wound healing. We developed an in vivo mouse model of injury to the anterior stroma that is sustained by PAF and evaluated the action of LXA(4). In this model mice were treated with vehicle, PAF alone and in combination with PAF receptor antagonist LAU-0901 or LXA(4). Mice were euthanized 1, 2 and 7 days after injury and corneas were processed for histology (H&E staining) and immunofluorescence with antibodies for MMP-9, α-smooth muscle actin (α-SMA), fibronectin (FN) and neutrophil. Interleukin 1-α (IL-1α) and keratinocyte-derived chemokine (KC/CXCL1) were assayed by ELISA. Myeloperoxidase (MPO) activity was performed in corneal homogenates. In this in vivo model PAF inhibited epithelial wound healing that was blocked by the PAF receptor antagonist LAU-0901. Treatment with LXA(4) significantly reduced the injured area compared to PAF at 1 and 2 days of treatment. The strong stromal cell infiltration and MPO activity stimulated by PAF was also decreased with LXA(4) treatment. PAF increased MMP-9 and decreased FN expression compared to vehicle treatment and less α-SMA positive cells migrated to the wounded area. The PAF actions were reverted by LXA(4) treatment. The results demonstrated a powerful action of LXA(4) in protecting corneas with injuries that compromise the stroma by decreasing inflammation and increasing wound healing.
血小板激活因子（PAF）是一种具有强烈炎症特性的生物活性脂质介质。PAF 诱导角膜上皮细胞和成纤维细胞中金属蛋白酶-9（MMP-9）的表达和激活，并在器官培养系统中延迟上皮伤口愈合。脂氧素 A4（LXA4）是一种参与炎症消退和角膜上皮伤口愈合的脂质介质。我们开发了一种体内小鼠模型，该模型中前基质的损伤由 PAF 维持，并评估了 LXA4 的作用。在该模型中，用载体、PAF 单独以及与 PAF 受体拮抗剂 LAU-0901 或 LXA4 联合处理小鼠。在损伤后 1、2 和 7 天处死小鼠，并对角膜进行组织学（H&E 染色）和免疫荧光分析，用 MMP-9、α-平滑肌肌动蛋白（α-SMA）、纤维连接蛋白（FN）和中性粒细胞的抗体进行分析。通过 ELISA 测定白细胞介素 1-α（IL-1α）和角质形成细胞衍生趋化因子（KC/CXCL1）。在角膜匀浆中进行髓过氧化物酶（MPO）活性测定。在该体内模型中，PAF 抑制上皮伤口愈合，这种抑制作用可被 PAF 受体拮抗剂 LAU-0901 阻断。与 PAF 治疗相比，LXA4 治疗在 1 和 2 天治疗时显著减少了受伤区域。LXA4 治疗还降低了 PAF 刺激的基质细胞浸润和 MPO 活性。与载体处理相比，PAF 增加了 MMP-9 的表达并减少了 FN 的表达，并且较少的 α-SMA 阳性细胞迁移到受伤区域。LXA4 治疗逆转了 PAF 的作用。结果表明，LXA4 在通过减少炎症和增加伤口愈合来保护因基质损伤而受损的角膜方面具有强大的作用。
