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1220 INVESTIGATIVE OPHTHALMOLOGY b VISUAL SCIENCE / October 1984 Key words: polymorphonuclear neutrophil, corneal epithelium, ulceration, wound healing, collagenolysis, electron microscopy From the Cornea Unit, Eye Research Institute of Retina Foundation* and the Department of Ophthalmology,! Harvard Medical School, Boston, Massachusetts. Supported in part by NIH grants EY-05718 (MDW), EY-03967 (KRK), EY-03306 (IKG), and the Heed Ophthalmic Foundation (MDW). Submitted for publication: April 9, 1984. Reprint requests: Dr. M. D. Wagoner, Eye Research Institute of Retina Foundation, 20 Staniford St., Boston, MA 02114. References 1. Cavanagh HD, Pihlaja D, Thoft RA, and Dohlman CH: The pathogenesis and treatment of persistent epithelial defects. Trans Am Acad Ophthalmol Otolaryngol 81:754, 1976. 2. Kenyon KR: Decision-making in the therapy of external eye disease: Noninfected corneal ulcers. Ophthalmology 89:44, 1982. 3. Sendele DD, Kenyon KR, Wolf G, and Hanninen LA: Epithelial abrasion precipitates stromal ulceration in the vitamin Adeficient rat cornea. Invest Ophthalmol Vis Sci 23:64, 1982. 4. Rivkin I, Rosenblatt J, and Becker EL: The role of cyclic AMP in the chemotactic responsiveness and spontaneous motility of rabbit peritoneal neutrophils. The inhibition of neutrophil movement and the elevation of cyclic AMP levels by catecholamines, prostaglandins, theophylline and cholera toxin. J Immunol 115:1126, 1975. Vol. 25 5. Gipson IK and Anderson RA: Effect of lectins on migration of the corneal epithelium. Invest Ophthalmol Vis Sci 19:341, 1980. 6. Snedecor GW and Cochran WG: Statistical Methods, seventh edition. Iowa State University Press. Ames, Iowa, 1980, pp. 144-145. 7. Pfister RR: The healing of corneal epithelial abrasions in the rabbit: A scanning electron microscopic study. Invest Ophthalmol 14:468, 1975. 8. Berman M: Collagenase and corneal ulceration. In Collagenase in Normal and Pathological Connective Tissues, Woolley DE and Evansorf JM, editors. Chichester, England, John Wiley & Sons, 1980, pp. 141-174. 9. Kenyon KR, Berman M, Rose J, and Gage J: Prevention of stromal ulceration in the alkali-burned rabbit cornea by gluedon contact lens. Evidence for therole of polymorphonuclear leukocytes in collagen degradation. Invest Ophthalmol Vis Sci 18:570, 1979. 10. Pfister RR, Nicolaro ML, and Paterson CA: Sodium citrate reduces the incidence of corneal ulcerations and perforations in extreme alkali-burned eyes—acetylcysteine and ascorbate have no favorable effect. Invest Ophthalmol Vis Sci 21:486, 1981. 11. Gipson IK, Riddle CV, Kiorpes TC, and Spurr SJ: Lectin binding to cell surfaces: Comparisons between normal and migrating corneal epithelium. Dev Biol 96:337, 1983. 12. Fujikawa LS, Foster CS, Harrist TJ, Lanigan JM, and Colvin RB: Fibronectin in healing rabbit corneal wounds. Lab Invest 45:120, 1981. An Improved Method for Restroining Robbits for Exominotion of the Eye Dovid M. Maurice and Tej Singh Rabbits are strapped to a specially shaped platform with their legs dangling over the sides. This system of restraint allows freer access to the eyes for examination than other methods and prevents the animal from injuring itself by kicking. The animals appear to be quite relaxed and show no signs of harm on release. Invest Ophthalmol Vis Sci 25:1220-1221, 1984 When the rabbit's eye has to be observed in the slit lamp or a minor diagnostic procedure such as applanation tonometry must be performed, it is necessary to immobilize the animal and to prevent evasive movements of the head as far as possible. The animal may be put under general anesthesia or be tranquilized heavily, but this can upset the normal metabolism, particularly if the observations or measurements have to be frequent or prolonged. Mechanical restraint is generally preferred for those procedures that are painless but can alarm the animal. The same is true for entering an ear vein with a needle and for minor ocular interventions under local anesthesia. Two forms of restraint are common. The first is to confine the rabbit in a box with its head protruding from a closure around the neck. This has several disadvantages. First, the box blocks slit-lamp observation of much of the eye; second, if the animal is frightened it will struggle and may injure itself; third, it can jerk its head away when a needfe is inserted into an ear vein, which requires reentry into a punctured and bleeding vessel. A more satisfactory procedure is to secure the animal firmly in a bag or some other cloth wrap. This prevents it harming itself and allows better access to the eye for observation. However, it is not easy to wrap the rabbit successfully, and this can be time-consuming, particularly if the animal is recalcitrant. Moreover, it still can jerk its head away on feeling a needle prick. We therefore have developed a system of restraint that goes a long way to avoid these disadvantages. Materials and Methods. The basis of the system is to make the rabbit lie on a narrow platform with its legs straddling it. When its paws have no purchase on a surface, it can only kick into the air, and its Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933345/ on 05/12/2017 Reporrs No. 10 principal escape mechanism is circumvented. A 6mm-thick aluminum plate was cut to the dimensions shown in Figure 1. This was supported about 20 cm above a baseplate on a pillar, which was located towards the rear (Fig. 2) so that the center column of a slit lamp could be accommodated under the head. The animal is held down by a Velcro strap in the small of the back and another around the shoulders. The head-rest of a slit lamp was removed and replaced with a platform arranged to bring the eyes to the level of the optics. The wide part of the platform supports the belly of the animal. Two side pieces are attached to prevent the animal from listing to one side if it is under general anesthesia; these are not necessary when it is conscious, since it.maintains its balance, but they do not interfere. If further restraint is needed, the neck can be tied down by a cloth ribbon or a narrow Velcro strip, or a wider strip around the ears can be used to fix the head. Animals generally can be mounted on the platform single-handedly, but this can be difficult if it is resistant. The process is eased by the use of a loading hopper. A narrow three-sided box, raised on a stand, was constructed to accommodate the front extension of the platform. The rabbit is placed in the top of the box and is pulled out by the skin of the lower back and its near legs pushed down to straddle the narrow part of the platform. The rear strap is then fixed firmly over the rabbit's back with the other hand. The platform and the rabbit are then slid out together until the front legs clear the box when the second strap is placed in the same way. Results and Discussion. There is as much freedom to examine the animal's eyes in the slit lamp with this method of restraint as is permitted by its anatomy. It has been adopted in the laboratory for several months and has been found advantageous by its users. The mounting procedure can be carried out successfully on the first attempt by an untrained person. The rabbit can be secured for observation within 15 sec of lifting it from the cage. The neck does not D 12.5cm Fig. 2. Rabbit fixed in restrainer. need to be tied for the purpose of examination in the slit lamp. Although the animals rarely move their heads when left alone, they become disturbed when they are rotated about a vertical axis in order to examine both eyes in turn. If this is to be frequent, or if total stillness is critical, as in some forms of fluorophotometry, it is convenient to use chlorpromazine as a tranquilizer. Although the posture of the animal is unnatural, there is no reason to suppose that it is physically uncomfortable. The rabbits do not struggle or squirm, although they can do so if deliberately frightened. On the contrary, they generally appear to be quite relaxed; some animals tense their leg muscles before they become accustomed to the position, but this does not result in their becoming dislodged. Some rabbits have been restrained for up to 1 hr. Upon release, they immediately hopped around in a normal manner, so evidently there is no undue pressure on the vessels or nerves of the legs. We have not had much occasion to use the system for venepuncture, but if the head is secured, the risk of jerking away from the syringe seems to be reduced. The engorgement of the veins can be assisted by tilting the platform foward so that the animal's head is below its body. Key words: animal restraint, eye examination -rvpiiiaT l2-5cm 1221 11cm Fig. 1. Dimensions of platform base. 14.5c From the Division of Ophthalmology, Stanford University School of Medicine, Stanford, California. Supported by NEI grant EY00431. Submitted for publication: February 27, 1984. Reprint requests: David M. Maurice, Division of Ophthalmology, S030. Stanford University Medical Center, Stanford, CA 94305. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933345/ on 05/12/2017