bcop basic-background-methods
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© 2009 MB Research Laboratories. All Rights Reserved.
Experience and Innovation
BCOPBovine Cornea Opacity & Permeability Test
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
• Uses excised Bovine Corneas normally discarded as waste
• Measures two endpoints:
1) Changes in light transmission
2) Trans-corneal Fluorescein permeability
BCOP: Bovine Cornea Opacity/Permeability Test Alternative Eye Irritation Model
Normal Opacity
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
BackgroundSince the cornea is of primary interest in assessing ocular irritation, the BCOP provides a useful parallel for possible human exposure.
Bovine corneas have been used since the early 1950s as an alternative ocular model.
Current BCOP evaluations were developed by Pierre Gautheron and Joseph Sina in 1992* as an alternative to the Draize Rabbit Eye Test .
Reviewed by ICCVAM as a regulatory alternative to the Draize Rabbit Eye Test.
Regulatory agencies accept BCOP for the purpose of classification for labeling under the Federal Hazardous Substance Act
* “Bovine Corneal Opacity and Permeability Test: An In Vitro Assay of Ocular Irritancy”, Gautheron P., Dukic, M., Alix, D. and Sina, J. Fundamental and Applied Toxicology 18, 442-449.
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
Assay Procedures
- The bovine eyes are harvested and shipped in cold HBSS.
- The corneas are carefully checked for any damage (opacity, cuts, vascularization, etc.) before being excised and mounted in the special BCOP chambers with Complete Minimal Essential Media in contact with the epithelium and endothelium.
- After a 1 hour incubation a pretest opacity reading is taken using an opacitometer, an instrument which measures light penetration through the cornea
- The corneas are divided into two groups – test article and control.
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
- Cornea is exposed to the test material. The material can be tested at any concentration and over a range of exposure times to differentiate potential mild to severe eye irritants.
Assay Procedures (cont.)
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- The test article is rinsed from the cornea, opacities scored and recorded before an additional incubation.
- Incubation times may be varied to enhance post exposure expression of irritancy.
- A post incubation opacity reading is taken on each cornea and recorded.
- Opacity readings are subtracted from the pretest opacity readings to calculate the Corrected Opacity Score.
Assay Procedures (cont.)
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
Normal
Opacity -Caused by swelling of basal epithelial cells.
BCOP - Opacity
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Different Optical Density Scores are measured by the amount of fluroscein that permeates through the cornea into the posterior chamber filled with Minimal Essential Media (MEM). Intensity of response increases with the amount of fluorescein permeability.
BCOP – Permeability
- A permeability test is performed to measure the passage of fluorescein stain through the cornea. A sample of the media is removed from the posterior end of the chamber and measured spectrophotometrically (490nm) to determine the amount of fluorescein leakage.
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InterpretationIn Vitro Score Classification
0 to 25 Mild Irritant
25.1 to 55 Moderate Irritant
55.1 & above Severe Irritant
Corneas may also be fixed, sectioned, and examined by a board certified pathologist.
Based upon our experience, test articles scoring 0 –4 are not a Draize Irritant, test articles scoring 4 – 10 are borderline, and test articles scoring 10 – 25 are mild to moderate Draize Irritants.
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
EpiOcular - 3D Human Tissue Models – Air/Liquid InterfaceChorioallantoic Membrane Vascular Assay
Tissue Culture Well
Culture Insert
ALI TissueMembrane
Medium
MB Research has pioneered the use and development of alternative and in vitro ocular toxicity models used mainly for cosmetics and consumer product safety evaluations. Since 1990, We have performed over 12,000 alternative ocular irritancy tests, which include approx. 3200 BCOPs to date.
BCOP can be used in combination with other alternatives such as the CAMVA or HET-CAM to further determined ocular irritancy classification.
Alternative Ocular Toxicology Models
© 2009 MB Research Laboratories. All Rights Reserved.Experience and Innovation
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