Isolated rabbit eye

Isolated rabbit eye (IRE) test method EU/US not sufficiently validated... 

Several in vitro methods, including the hen s egg chorioallantoic membrane test (HET-CAM) the bovine cornea opacity and permeability assay (BCOP) and the isolated rabbit eye (IRE) test, have gained regulatory acceptance in Europe for the classification of severe eye irritants. Many companies are using such techniques successfully to reduce in vivo testing during development. ... 

Jester, J.V, Ling, J., HarbeU, J. Measuring depth of injury (DOI) in an isolated rabbit eye irritation test (IRE) using biomarkers of cell death and viability. Toxicol In Vitro 24(2), 597-604 (2010). Epub 2009 Oct 24... 

The Isolated Rabbit Eye (IRE) test has been developed as an in vitro alternative to the in vivo Draize rabbit eye test method for the assessment of eye irritation [68]. In the IRE assay, liquid test substances are spread using a syringe and solids are pulverized and applied as a powder over the corneas of enucleated rabbit eyes. The test [also referred to as the Rabbit Enucleated Eye Test (REET)] makes use of eyes from animals used in the food chain or for other toxicological studies. 

Cooper KJ, Earl LK, Harbell J, Raabe H (2001) Prediction of ocular irritancy of prototype shampoo formulations by the isolated rabbit eye (IRE) test and bovine corneal opacity and permeability (BCOP) assay. Toxicology In Vitro 15 95-103... 

The isolated rabbit eye (IRE) test (Burton et al, 1981) determines the opacification of the cornea and the increase in corneal thickness (comeal swelling) after exposure to irritant substances. Whole eyeballs obtained by immediate dissection from humanely killed laboratory rabbits with healthy eyes are mounted and maintained in a vertical position in a superfusion chamber, with controlled temperature and humidity. This ensures that the eyes remain viable throughout the duration of the test. Pre-warmed saline solution is applied drop by drop directly onto the cornea at regular intervals to keep it moist. 

Figure 9.13 Visual assessment of comeal opacity (a) and uptake of sodium fluorescein dye by the cornea (b) in isolated rabbit eye test (adapted from Safepharm Laboratories, Derbyshire UK, in ).

XP Shi, OA Candia. (1995). Active sodium and chloride transport across the isolated rabbit conjunctiva. Curr Eye Res 14 927-935. 

Our body is used to repair small accidents of mechanical or chemical origin. These accidents of biological origin are due to stinging by nettles or insects on eye and skin. Further, there are mechanical damages that are used to be repaired within a short time - as seen in the ex vivo eye irritation test (EVEIT) - such as the healing of mechanical damage ex vivo within a short period of 3 days observed on the isolated rabbit cornea (Fig. 5.11a and b). 

Cetylpyridinium chloride Inclusion of 0.02% cetylpyridinium chloride with pilocarpine nitrate applied topically to the rabbit eye was found to cause a miotic effect 10 times that obtained in the absence of cetylpyridinium [64]. In another study, cetylpyridinium chloride was shown to enhance penicillin penetration across the isolated rabbit cornea [65] with an intact epithelial layer. The penetration was even more than that shown by the de-epithelialized corneas. 

All the official recommended methods for determining the ocular Irritation potential of a chemical derive from the Draize rabbit eye test (Draize et al., 1944). Despite of its historical impact, to day most scientists as well as the general public are disapproved of the Draize test for ethical and scientific reasons (Sharpe, 1985, Swanston, 1985). A number of in vitro test systems were described, e.g. the isolated eyes (Price and Anders, 1985), the embryonated hen s egg-choriallantoic membrane (HET-CAM) test (Luepke, 1985), the neutral red/kenacid blue method (Borenfreund and Puermer, 1985 Knox et al., 1986 Riddell et al., 1986), or the EYTEXR method (Martin, 1993 Regnier, 1994). 

Cole, D.F. (1984). Sensory and neural mechanisms in contraction of the rabbit isolated spincter pupillae. Exp. Eye Res. 38, 153-163. 

Ocular damaging and irritant agents can be identified and evaluated by the Draize rabbit test [114]. However, more recently this test has been criticized on the basis of ethical considerations and unreliable prognosis of human response. Alternative methods such as the evaluation of toxicity on ocular cell cultures have been recommended and are being indicated as promising prognostic tools [115-120]. Direct confocal microscopic analysis [121], hydration level of isolated corneas [122], and various other tests on isolated corneas or animal eyes have also been proposed for evaluation of ocular toxic effects. 

Perrot S, DutertreCatella H, Martin C et aL (2003) Rezasurin metabolism assay is a new sensitive alternative test in isolated pig cornea. Toxicol Sci 72 122-129 Prinsen MK, Koeter HB (1993) Justification of the enucleated eye test with eyes of slaughterhouse animals as an alternative to the Draize eye irritation test with rabbits. Food Chem Toxicol 31 69-76... 

The presence of substantial amounts of flavins in retina has been known for some time. The detailed function of the light-sensitive flavins in the eye as well as pathophysiological consequences of riboflavin deficiency or overload conditions are not known to date. Batey and coworkers have analyzed the flavin content in retinal tissue from rats and rabbits in some detail (76-78). Retinas from two to three rats were isolated and homogenized. Flavins were extracted by a hot water treatment and analyzed by reversed-phase HPLC (Table 5). The... 

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