何為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.

牛角膜混濁和通透性試驗（BCOP ）是一項體外眼刺激試驗，由Gautheron et al. (1992)研究開(kāi)發(fā)而來(lái)。該試驗使用從屠宰場(chǎng)獲取的新鮮牛角膜評估供試品的潛在眼刺激性。通過(guò)牛眼角膜渾濁度和對熒光素的通透性改變，定量檢測供試品暴露所致的損傷類(lèi)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試驗可用于研究導致?lián)p傷的機制。蛋白變性或基質(zhì)腫脹可導致角膜混濁，而角膜屏障功能和角膜上皮細胞之間細胞膜的連接受損則可表現為角膜通透性改變。

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，也可補充組織學(xué)終點(diǎn)指標，以評估角膜腫脹、脫水或形態(tài)學(xué)上的改變。組織學(xué)評估主要在于評價(jià)觀(guān)察到的損傷類(lèi)型以及角膜的損傷深度。

Assay Model:

Organotypic, bovine corneas (obtained as a by-product from abattoirs)

試驗模型 牛眼角組織（取自屠宰場(chǎng)的副產(chǎn)品）

Endpoints:

1. Opacity (determined by measuring the amount of light transmitted through the cornea).
2. Permeability (determined by measuring the amount of fluorescein dye that penetrates through the cornea).

終點(diǎn)指標

1 濁度值，通過(guò)測量角膜的透光量確定

2 通透性，通過(guò)測量滲透過(guò)角膜的熒光素染料數量確定

Each assay includes a positive and negative control.

每次試驗均設置陽(yáng)性對照和陰性對照。

Sensitivity

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.

靈敏度

BCOP主要用于評價(jià)中重度眼刺激/腐蝕的測試物。不過(guò)，可修改暴露方案，以提高試驗系統的敏感性，進(jìn)而用于輕度眼刺激/腐蝕性制劑成分的評價(jià)。

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.

測試物的兼容性

本試驗可用于水溶性制劑，也可用于不可溶制劑；可測試固體測試物，也可測試液體測試物。由于測試物是局部給藥，因此本試驗系統也適用于乳劑、糊劑、高粘性物質(zhì)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.

備選終點(diǎn)

BCOP有多個(gè)終點(diǎn)指標，可進(jìn)行機制研究。此外，可補充組織學(xué)終點(diǎn)指標，以評價(jià)觀(guān)察到的損傷類(lèi)型和深度?；贛aurer and Jester (2002)的研究工作，損傷的深度和程度可用于預測嚴重程度和角膜損傷的結局。

必要時(shí)，可調整供試品濃度和暴露時(shí)間，使之適應于特定的物理性質(zhì)或客戶(hù)需求。

Validation

• 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和歐洲，BCOP已獲批用于鑒別腐蝕性物質(zhì)和鑒別按UN GHS無(wú)需分類(lèi)的化學(xué)物

OECD指導原則 (TG437)已于2009年被采納，并在2013年接受了修訂

US EPA 接受采用BCOP試驗作為給清潔用品貼簽抗菌聲稱(chēng)的分級策略之一。

HISTOLOGY

組織學(xué)

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.

根據研究目的，可能會(huì )采取多種方式運用組織學(xué)評價(jià)結果。組織學(xué)結果可用于確認濁度值和通透率預測得到的角膜刺激性級別。另外，其還可用于闡釋測試物導致角膜損傷的類(lèi)型和深度。

補充

BCOP試驗過(guò)程

簡(jiǎn)圖如下，具體參見(jiàn)SN/T 4153-2015 化學(xué)品 牛角膜混濁和通透性試驗 和 OECD437

局限性

BCOP的局限性主要表現在沒(méi)有考慮受試物對虹膜和結膜的刺激作用，某些物質(zhì)可能對結膜有損傷，但對于角膜的作用不明顯，如果只采用BCOP可能只反應了化合物的角膜損傷作用而忽視對結膜的可能作用。

題外話(huà)

眼刺激性試驗擱在2009年之前，大多都是在活體家兔身上做【具體過(guò)程可參考[檢驗檢測標準]GBT 21609-2008 化學(xué)品 急性眼剌激性/腐蝕性試驗 規范】。但隨著(zhù)科技進(jìn)步和動(dòng)物福利的呼聲高漲，活體動(dòng)物試驗漸漸開(kāi)始為人詬病，畢竟兔也有兔權的嘛！于是就有科學(xué)家開(kāi)發(fā)了這項離體試驗，用人類(lèi)食用動(dòng)物宰殺后的離體眼球代替活體動(dòng)物。打個(gè)比方，研究員李四要測試一下自家洗發(fā)水對眼睛有沒(méi)有刺激性，本來(lái)要弄只兔子做試驗，碰巧發(fā)現鄰居張三要宰牛，反正這牛要上餐桌了，牛眼也不好吃，棄了挺可惜，拿來(lái)做試驗剛剛好，還能為科學(xué)做點(diǎn)貢獻。這不就變廢為寶，一舉兩得，順便在解剖刀下救下一只了兔子么。

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