Davis Michael W, Stephenson Jeana, Noga Edward J
National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center, 2030 Southeast Marine Science Drive, Newport, Oregon 97365, USA.
J Aquat Anim Health. 2008 Jun;20(2):86-95. doi: 10.1577/H07-023.1.
Fluorescein has been used for rapid and sensitive detection of fish skin and corneal ulceration. Effective use of the fluorescein test requires knowledge of conditions that might cause misleading interpretations or otherwise interfere with test reliability. Examination of fish health and the clinical workup often require tricaine as one of the most commonly used anesthetics. However, tricaine may interfere with correct interpretation of the fluorescein test and might also cause significant fish injury. The effects of tricaine exposure sequence on the fidelity of the fluorescein test was studied in Pacific halibut Hippoglossus stenolepis, walleye pollock Theragra chalcogramma, and northern rock soles Lepidopsetta polyxystra by examining the fluorescence of experimentally induced epidermal wounding. Tricaine can quench fluorescence that is emitted by fluorescein retained in skin ulcers, causing a false-negative reaction. Thus, for the fluorescein test to work properly, it is important to avoid the exposure of fluorescein-treated and rinsed ulcers to tricaine. The effects of exposure to buffered versus unbuffered tricaine on epidermal and corneal integrity were studied in Nile tilapia Oreochromis niloticus and channel catfish Ictalurus punctatus subjected to the fluorescein test and histological examination. Fluorescein could detect not only ulcers but also areas with only a partial loss of epithelium (i.e., erosion). The use of unbuffered tricaine to anesthetize these fish caused serious epidermal and corneal damage. If fish are euthanized with unbuffered tricaine for clinical workup, this severe epidermal or corneal damage could be misinterpreted as an antemortem lesion, leading to misdiagnosis. Even in water with alkalinity exceeding 50 mg/L as CaCO3, it would seem prudent to always buffer tricaine with sodium bicarbonate to prevent a pH change that might lead to iatrogenic effects from unbuffered tricaine. Thus, current general recommendations suggesting that tricaine does not need to be buffered in waters with alkalinity greater than 50 mg/L might need to be modified.
荧光素已被用于快速、灵敏地检测鱼的皮肤和角膜溃疡。有效使用荧光素试验需要了解可能导致误导性解读或干扰试验可靠性的情况。检查鱼的健康状况和进行临床检查时，通常需要使用tricaine作为最常用的麻醉剂之一。然而，tricaine可能会干扰荧光素试验的正确解读，还可能对鱼造成严重伤害。通过检测实验诱导的表皮伤口的荧光，研究了tricaine暴露顺序对太平洋大比目鱼（Hippoglossus stenolepis）、狭鳕鱼（Theragra chalcogramma）和多斑新平鲉（Lepidopsetta polyxystra）荧光素试验准确性的影响。tricaine会淬灭皮肤溃疡中保留的荧光素发出的荧光，导致假阴性反应。因此，为使荧光素试验正常进行，避免用荧光素处理并冲洗后的溃疡接触tricaine非常重要。在接受荧光素试验和组织学检查的尼罗罗非鱼（Oreochromis niloticus）和斑点叉尾鮰（Ictalurus punctatus）中，研究了暴露于缓冲和未缓冲的tricaine对表皮和角膜完整性的影响。荧光素不仅可以检测溃疡，还可以检测仅上皮部分缺失的区域（即糜烂）。使用未缓冲的tricaine麻醉这些鱼会导致严重的表皮和角膜损伤。如果用未缓冲的tricaine对鱼实施安乐死以进行临床检查，这种严重的表皮或角膜损伤可能会被误诊为生前病变，从而导致误诊。即使在碱度超过50 mg/L（以碳酸钙计）的水中，似乎也应始终用碳酸氢钠缓冲tricaine，以防止pH值变化可能导致未缓冲的tricaine产生医源性影响。因此，目前普遍建议在碱度大于50 mg/L的水中不需要缓冲tricaine，这一建议可能需要修改。
