Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky 40202, USA.
J Ocul Pharmacol Ther. 2009 Dec;25(6):483-6. doi: 10.1089/jop.2008.0134.
Lipoxins exert potent anti-inflammatory and pro-resolving actions by reducing polymorphonuclear neutrophil (PMN) infiltration. This study describes the effect of lipoxin A4 and a stable analog on the resolution of ocular inflammation induced by intravitreal injection of lipopolysaccharides (LPS) in rats.
Six- to eight-week-old male Sprague Dawley (SD) rats were injected intravitreally with 2.5 microL physiologically balanced solution (LPS) containing 5 ng LPS, or 5 ng LPS + 50 ng LXA4 or 5 ng LPS + 50 ng 15-epi-LXA4 analog. Rats were anesthetized with intraperitoneal injection of a ketamine and xylazine cocktail. At 24 h, the animals were again anesthetized and the eyes examined for clinical signs of inflammation. The animals were then euthanized by CO2 inhalation and aqueous humor was collected in heparinized saline. Aqueous humor PMNs were counted using an Improved Neubauer Hemocytometer, and the protein concentration was determined by standard procedure. After enucleation, the eyes were dissected to remove the lens and the ocular tissues were frozen in liquid nitrogen and stored at -80 degrees C. Myeloperoxidase assay was done by a standard procedure.
Compared to untreated LPS-injected controls, rats treated with either LXA4 or its stable analog had lower clinical inflammation score, significantly reduced aqueous humor PMN cell counts, aqueous humor protein levels, and the MPO values. The difference between the mean values of aqueous humor protein and MPO in the LXA4 and the analog injected eyes was not statistically significant, but PMN cell counts were significantly different.
The ocular inflammatory response to intravitreally injected LPS in rats is significantly reduced by simultaneous injection of LXA4 or its analog. This finding supports an earlier independent observation of the ocular anti-inflammatory effect of LXA4. Further investigation of lipoxins in the eye might offer a novel therapeutic approach to treating ocular inflammation in man.
脂氧素通过减少多形核中性粒细胞（PMN）浸润发挥强大的抗炎和促解决作用。本研究描述了脂氧素 A4 和稳定类似物对大鼠眼内注射脂多糖（LPS）引起的眼内炎症消退的影响。
6 至 8 周龄雄性 Sprague Dawley（SD）大鼠经玻璃体腔内注射 2.5 微升含有 5ng LPS 的生理平衡溶液（LPS），或 5ng LPS+50ng LXA4 或 5ng LPS+50ng 15-epi-LXA4 类似物。大鼠用腹腔注射氯胺酮和甲苯噻嗪混合物麻醉。24 小时后，再次麻醉动物并检查眼部炎症的临床体征。然后用二氧化碳吸入法处死动物，用肝素化生理盐水收集房水。用改良 Neubauer 血细胞计数器计数房水中的PMN，用标准程序测定蛋白浓度。眼球摘除后，将眼球解剖以去除晶状体，将眼组织在液氮中冷冻并储存在-80°C。通过标准程序进行髓过氧化物酶测定。
与未治疗的 LPS 注射对照相比，用 LXA4 或其稳定类似物治疗的大鼠具有较低的临床炎症评分，显著降低房水中的PMN 细胞计数、房水中的蛋白水平和 MPO 值。LXA4 和类似物注射眼房水中蛋白和 MPO 的平均值之间的差异无统计学意义，但PMN 细胞计数有显著差异。
同时注射 LXA4 或其类似物可显著减轻大鼠玻璃体腔内注射 LPS 引起的眼内炎症反应。这一发现支持了先前关于 LXA4 对眼部抗炎作用的独立观察。进一步研究脂氧素在眼部的作用可能为治疗人类眼部炎症提供一种新的治疗方法。
