Br J Ophthalmol: first published as 10.1136/bjo.68.9.656 on 1 September 1984. Downloaded from
British Journal of Ophthalmology, 1984, 68, 656-659
Topical indomethacin effect on neovascularisation of the cornea and on prostaglandin E2 levels
J. FRUCHT AND H. ZAUBERMAN From the Department of Ophthalmology, Hadassah University Hospital, Jerusalem, Israel
SUMMARY The effect of indomethacin 1% drops against a placebo (NaCl 09% solution) was tested in rabbits' corneas injured by a standardized chemical burn. The corneas treated with indomethacin 1% had less neovascularisation and a much smaller increase in the PGE2 levels as compared with the control fellow eyes treated with a placebo. It appears that indomethacin 1% drops have a clear effect on the inflammatory response of the cornea and deserve a clinical trial in selected patients suffering from corneal inflammatory changes.
Prostaglandins are widely distributed in mammalian burns resulting from this injury were seen to be tissues.' Although the intimate mechanism of their of similar size and depth when examined with an synthesis and release are not well known, many tissues operating microscope. The effect of aqueous suspen-
can be non-specifically stimulated to produce more sion of 1% indomethacin drops (provided by Merck copyright. prostaglandins than they contain.' Release of Sharp and Dohme) on the injured corneas was investi- prostaglandins is associated with ocular inflamma- gated in terms of its influence on corneal neovascular- tion,' but their exact role in inflammation has not isation (11 rabbits) and also its effect on the levels of been identified. The demonstration of prostaglandins PGE, released (9 rabbits). This study was performed in the tissues of chronic ocular inflammation is of in a single-masked format: one eye was given a 1% interest.' A high content of leucocyte phospholipase indomethacin, 1 drop 3 times a day, while the fellow provides the inflamed tissue with a possible source of eye was given NaCl 0 9%, 1 drop 3 times a day. The prostaglandin E, (PGE2), and it is not difficult to drops were given by a laboratory technician, and the imagine clinical situations in which this mechanism examiners were not informed about the medication http://bjo.bmj.com/ could be a continuous source of the hormone. given to each eye. In the present study we stimulated an inflammatory The eyes were evaluated in terms of corneal neo- reaction in the cornea of rabbits by means of a vascularisation as follows: the ingrowth from the standardised chemical burn, and used this model to limbus was measured with the help of a caliper 7 days, investigate the effect of indomethacin 1%, a topical 17 days, and 27 days after the alkali burn. Photo- antiprostaglandin agent, on the corneal neovascular graphic records of the neovascular reaction were
response to the injury and also on the levels of PGE, taken during these measurements. For the purpose of on September 24, 2021 by guest. Protected in the tissue. this study the vascularisation was graded from 1 to 4 as follows: grade 1, engorged limbal vessels; grade 2, Materials and methods less than 1-0 mm ingrowth of vessels into the cornea; grade 3, 1-25-3 mm; grade 4, more than 3-25 mm Twenty albino rabbits were used for this study. The (Fig. 1). experiments were done under the effect of topical Statistical evaluation was done using the SPSS anaesthesia with oxybuprocaine (Novesine) 0 25% in software package. Krushkall-Wallis one-way analysis each eye. A standard epithelial and stromal lesion of variance was applied for the neovascularisation was performed with 10% sodium hydroxide. For this progress in the treated and untreated groups during purpose a filter paper 6 mm in diameter was soaked the follow-up period, and the Mann-Whitney U-test with the solution of 10% sodium hydroxide and placed served for the analysis of neovascularisation in the on the central cornea for 10 seconds. The corneal treated and the untreated eyes at any given time. Correspondence to Dr J. Frucht, Hadassah Univcrsity Hospital, PO The PGE, levels in the injured corneas were studied Box 12()(), i1-91 120 Jcrusalem. Isracl. as follows: in four rabbits the injured corneas were 656 Br J Ophthalmol: first published as 10.1136/bjo.68.9.656 on 1 September 1984. Downloaded from
Topical indomethacin effecton neovascularisation ofthe cornea and on prostaglandin E2 levels 657
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Fig. 1 Grading ofcornealneovascularisation in corneas ofrabbits. A=grade l; B=grade2; C=grade3; D=grade 4. http://bjo.bmj.com/ removed after two days and in five rabbits six days after the corneal injury. The corneal tissue was +41 *Y* ooo homogenised with the help of polytrone P 10-00 on c 1*0 ml of 50 mM TRIS HCL buffer, containing 0 ethylenediamine tetra-acetic acid (EDTA) 02 M at +31 -0 000 0 7*0. The -0 pH homogenate was extracted twice with on September 24, 2021 by guest. Protected two volumes of ether, and both the aqueous phase tn and the incubation media were assayed for PGE2 u +21 o0 00 0 concentration using a radioimmunoassay.3 The stat- C)0 istical evaluation of the PGE2 levels was done by the method of Wilcoxon matched-pairs signed ranks test. 0 +11 000 Histological preparation of 12 comeas (six rabbits) were done 30 days after the corneal injury. The tissue 4, was stained with haematoxylin and eosin and 0 0 7 17 27 examined under a light microscope. Days after burn injury Results Fig. 2 Neovascularisation in corneas treated with an aqueous suspension ofindomethacin 1% or with a placebo. 0 Corneal neovascularisation in control eyes. [: Corneal Neovascularisation in corneas treated with an aqueous neovascularisation in indomethacin 1% treated suspension of indomethacin 1% or with a placebo. eyes. 0 Corneas treated with NaCl 0-9%. 0 Corneas treated with Fig. 2 shows that the degree ofcorneal neovascularisa- indomethacin I %. Br J Ophthalmol: first published as 10.1136/bjo.68.9.656 on 1 September 1984. Downloaded from
658 J. Frucht MD and H. Zauberman MD
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Fig. 3A Light microscopicpreparation ofone rabbit with Fig. 3B Moresevere cornealscarring with infiltration of injured corneas. There is a mildcornealscarring and white blood cells. This cornea was treated with aplacebo. infiltration ofwhite blood cells. This cornea was treatedfor (HE, x38). 30 days with indomethacin 1%. tion in both groups increased gradually during the the treated and the untreated corneas two and six http://bjo.bmj.com/ follow-up period. However, the rate of neovascular- days after the injury. The PGE2 levels in both groups isation was more advanced in the eyes that received two days after the injury were by far more elevated NaCl 09% (p<0.001) than in the eyes treated with (p<0.01 in both groups) than the corresponding 1% indomethacin (p<005). Furthermore at any groups after six days. However, at any given time given time after the injury the eye receiving the there were larger PGE2 levels in the untreated group placebo had a more advanced degree of neovascular- of corneas than in the treated one (p<0009 two days, isation. The statistical difference in the degree of p
Topical indomethacin effecton neovascularisation ofthe cornea and onprostaglandin E2 levels 659 indicate that it can be worthwhile to try topical '3 100 indomethacin in patients with chronic corneal in- In flammation to test its possible anti-inflammatory potential. C' E We are grateful to Merk Sharp and Dohme Co. for providing the indomethacin aqueous solution 1% drops. We are also grateful to D. Rachmilewits and F. Karmeli, from the Department of Gastro- enterology, for measuring the PGE2 levels, and to T. Chachek, from -,, 50 the Internal Medicine Department, for the use of polytrone. w w References -j 1 Sears ML, Neufeld AH and Jampol LM. Prostaglandins. Invest w Ophthalmol Visual Sci 1973; 12: 161-4. 0 2 Eakins KE, Whitelocke RAF, Bennet A, Martene AC. Prosta- a. glandin-like activity in ocular inflammation. Br Med J 1972; iii: OL 452-3. 6 3 Bauminger S, Zor U, Linder HR. Radioimmunological assay of 2 prostaglandin synthetase activity. Prostaglandins 1973; 4: 313- DAYS AFTER CORNEAL INJURY 24. 4 Fromer CH, Klintworth GK. An evaluation of the role of leuko- Fig. 4 PGE2 levels in a group ofinjured corneas treated cytes in the pathogenesis of experimentally induced corneal with aqueous suspension ofindomethacin 1% or with a vascularization. I. Comparison ofexperimental modelsofcorneal placebo. PGE2 levels in control eyes. Ez PGE2 levels in vascularization. Am J Pathol 1975; 79: 537-54. indomethacin 1% treated eyes. 5 FromerCH, KlintworthGK. II. Studies ofthe effectof leukocytic elimination on corneal vascularization. Am J Pathol 1975; 81: 531-41. results in less neovascularisation of the injured 6 Fromer CH, Klintworth GK. III. Studies related to the vasopro- cornea, a lower degree of comeal infiltration with liferative capability of polymorphonuclear leukocytes and a of lymphocytes. Am J Pathol 1976; 82: 157-67. copyright. inflammatory cells, and also lower concentration 7 BenEzra D. Neovasculogenic ability of prostaglandins growth PGE2 levels as compared with placebo treated injured factors and synthetic chemoattractants. Am J Ophthalmol 1978; comeas. 86:455-61. In previous studies topical indomethacin reduced 8 Vane J. Inhibition of prostaglandins synthesis as a mechanism of the of action for aspirin-like drugs. Nature New Biol 1971; 231: 232-5. deleterious effect of thermal injury and also 9 Bhattacherjee P, Eakins KE. Inhibition of the prostaglandin prolonged use of contact lenses.'0 11 However, when synthetase systems in ocular tissues by indomethacin. Br J the drug was injected below Tenon's space it had no Pharmacol 1974; 50: 227-30. effect on corneal neovascularisation.'2 We have no 10 Deutch TA, Hughes WF. Suppressive effects ofindomethacin on thermally induced neovascularization of rabbit corneas. Am J clear for the except that a http://bjo.bmj.com/ explanation discrepancy Ophthalmol 1979; 87: 536-40. different route of indomethacin administration was 11 Duffin RM, Weissman BA, Glasser DB, Pettit TH. Flurbiprofen used. in the treatment ofcorneal neovascularization induced by contact Indomethacin 1% drops have been used effectively lenses. Am J Ophthalmol 1982; 93: 607-14. in clinical to reduce the inflammatory 12 Crabb CV. Endocrine influences of ulceration and regeneration ophthalmology in the alkali-burned corneas. Arch Ophthalmol 1977; 95: 1866- response of the iris produced by cataract surgery'3 70. and has also been reported to have some effect on the 13 Katz IM. Indomethacin. Ophthalmology 1981; 88: 455-8. 14 Kraff MC, Sanders RS, Jampol LM, Payman GA, Liebman HL. prevention of cystoid macular oedema after this on September 24, 2021 by guest. Protected operation. 14 15 To the best of our knowledge this drug Prophylaxis of pseudophakic cystoid macular edema with topical indomethacin. Ophthalmology 1982; 89: 885-90. has not yet been tested in terms ofits clinical effects in 15 Jampol LM. Pharmacologic therapy of aphakic cystoid macular chronic corneal inflammation in man. This study may edema. Ophthalnology 1982; 89: 891-7.