什么是BCOP?
The BCOP (Bovine Corneal Opacity and Permeability) assay is an in vitro eye irritation test method developed by Gautheron et al. (1992), which uses living bovine corneal tissue, obtained as a by-product from abattoirs, to evaluate the potential ocular irritancy of a test article. Types of injury caused by exposure to the test article are quantitatively measured by changes in opacity and permeability to fluorescein.
牛角膜混浊和通透性试验（BCOP ）是一项体外眼刺激试验，由Gautheron et al. (1992)研究开发而来。该试验使用从屠宰场获取的新鲜牛角膜评估供试品的潜在眼刺激性。通过牛眼角膜浑浊度和对荧光素的通透性改变，定量检测供试品暴露所致的损伤类型。
The BCOP assay allows for the investigation of the mechanism of the damage caused. Corneal opacity can be caused by protein denaturation or the induction of stromal swelling, while corneal permeability reflects a loss in corneal barrier function and cell-to-cell membrane junctions of the corneal epithelium.
BCOP试验可用于研究导致损伤的机制。蛋白变性或基质肿胀可导致角膜混浊，而角膜屏障功能和角膜上皮细胞之间细胞膜的连接受损则可表现为角膜通透性改变。
An additional histological endpoint can be added to assess the corneal swelling, hydration, or morphological alterations in the cornea. This assessment evaluates the type of observed lesions and the depth of injury into the corneas.
此外，也可补充组织学终点指标，以评估角膜肿胀、脱水或形态学上的改变。组织学评估主要在于评价观察到的损伤类型以及角膜的损伤深度。
Assay Model:
Organotypic, bovine corneas (obtained as a by-product from abattoirs)
试验模型：牛眼角组织（取自屠宰场的副产品）
Endpoints:
Opacity (determined by measuring the amount of light transmitted through the cornea).
Permeability (determined by measuring the amount of fluorescein dye that penetrates through the cornea).
终点指标：
1 浊度值，通过测量角膜的透光量确定
2 通透性，通过测量渗透过角膜的荧光素染料数量确定
Each assay includes a positive and negative control.
每次试验均设置阳性对照和阴性对照。
BCOP is primarily used to evaluate test materials in the moderate to extreme irritancy/corrosive range. However, exposure protocol modifications can be made to increase the sensitivity of the assay system to resolve among milder ingredients and formulations.
灵敏度
BCOP主要用于评价中重度眼刺激/腐蚀的测试物。不过，可修改暴露方案，以提高试验系统的敏感性，进而用于轻度眼刺激/腐蚀性制剂成分的评价。
Test Material Compatibility
The assay is compatible with both water soluble and insoluble formulations. Both solid and liquid test materials can be tested. Since test materials are topically applied, the test system is suitable for creams, pastes, highly viscous materials, and powders.
测试物的兼容性
本试验可用于水溶性制剂，也可用于不可溶制剂；可测试固体测试物，也可测试液体测试物。由于测试物是局部给药，因此本试验系统也适用于乳剂、糊剂、高粘性物质和粉末。
Alternate Endpoints
BCOP’s multiple endpoints allow the investigations of mechanism of action. An additional histological endpoint can be added to assess the types of observed lesions and the depth and degree of injury. Based upon the work of Maurer and Jester (2002), the depth and degree of injury may be used to predict the severity and outcome of the corneal injury.
Test article concentrations and exposure times may be adjusted as necessary to accommodate specific physical characteristics or client needs.
备选终点
BCOP有多个终点指标，可进行机制研究。此外，可补充组织学终点指标，以评价观察到的损伤类型和深度。基于Maurer and Jester (2002)的研究工作，损伤的深度和程度可用于预测严重程度和角膜损伤的结局。
必要时，可调整供试品浓度和暴露时间，使之适应于特定的物理性质或客户需求。
In the US and in Europe, the BCOP assay has been approved for identification of corrosive substances and those chemicals not requiring classification according to UN GHS.
OECD Test Guideline was adopted (TG437) in 2009 and revised in 2013.
The US EPA accepts the BCOP assay as part of a tiered strategy for the labeling of cleaning products with anti-microbial claims.
有效性
在US和欧洲，BCOP已获批用于鉴别腐蚀性物质和鉴别按UN GHS无需分类的化学物
OECD指导原则 (TG437)已于2009年被采纳，并在2013年接受了修订
US EPA 接受采用BCOP试验作为给清洁用品贴签抗菌声称的分级策略之一。
组织学
The results of a histological evaluation may be used in several ways depending on the study goals. It may be used to confirm the level of corneal irritation predicted by the opacity and permeability values. In other cases, it is helpful to understand the types of lesions and the depth of injury that a material might induce in the cornea.
根据研究目的，可能会采取多种方式运用组织学评价结果。组织学结果可用于确认浊度值和通透率预测得到的角膜刺激性级别。另外，其还可用于阐释测试物导致角膜损伤的类型和深度。
具体参见SN/T 4153-2015 化学品 牛角膜混浊和通透性试验 和 OECD437
局限性
BCOP方法的局限性主要表现在没有考虑受试物对虹膜和结膜的刺激作用，某些物质可能对结膜有损伤，但对于角膜的作用不明显，如果只采用BCOP方法可能只反应了化合物的角膜损伤作用而忽视对结膜的可能作用。
