| The most common complication of extracapsular cataract extraction (ECCE) with or without posterior chamber intraocular lens (IOL) is posterior capsule opacification (PCO). This condition is usually secondary to the migration, proliferation, and metaplasia of the residual epithelial cells, so the prevention and treatment of PCO is alike to that of cancers. Pharmacological inhibition of PCO by antimitotics is a promising concept. 5-FU specifically acted on mitotic cells by inhibiting the enzyme thymidylate synthetase. Hence , the tissues of the posterior chambers of the eye, such as corneal endothelial cells and iris pigment and retina, should not be affected by the action of 5-FU. As most of the LECs have been in S-phase of DNA synthesis, so it is beneficial to increase the contact time between the drugs and LECs intraoperatively or at the early time postoperatively. This experiment intended to determine whether an intraoperative single dose of different concentrations of 5-FU was a phamacological means of preventing or reducing the development of posterior capsule opacification (PCO). Method40 New Zealand rabbits weighing 2.0 to 2.5kg were used. The animals were randomly divided into 4 groups. ECCE was performed in the left eyes, and the drugs were administered intraoperatively. Three different concentrations of 5-FU (0.05mg/ml, 0.1mg/ml, 0.2mg/ml) were given by hydrodissection. The fouth group served as a control group. The changes of the incision, cornea, anterior chamber were observed at 1, 3, 7, 14 day postoperatively. The development of PCO was assessed by slitlamp biomicroscopy at 2 weeks and 1, 2, 3 months, and photographed by slitlamp camera. The PCO was graded on ascale of 0-3 : 0=clear, no visible proliferative tissue on the peripheral or central posteriorcapsule; l=mild, proliferative tissue in the peripheral area only; 2=moderate, sparseproliferative tissue on the peripheral and central capsules; 3=dense, diffuse, and thickopacification on the entire capsule. After 3 months , the rabbits were humanly killed and theeyes were enucleated. The globes were placed in buffered formalin 10% and sectioned in thecoronal plane just anterior to the equator. The anterior segment of each eye was stained withhematoxylin-eosin (H&E). Histological analysis was then performed using the lightmicroscope.Results1 . The conjunctival reaction to operationAll eyes had conjunctival hyperemia during the first 3 days postoperatively, which disappeared at one week. On the 7th day, the number of eyes that had hyperemia had no significant difference(P<0.05). 2. The corneal reaction to the surgeryThe corneal area around the incision was relatively edematous in all eyes during the first week. The most common complication postoperatively was mild to moderate corneal edema that disappeared spontaneously at 1 week. On day 1 and 7, the number of eyes that still had corneal edema had no significant difference(P>0.05). 3 . The anterior chamber reaction to the surgeryThe degree of aqueous flare was(++) in most of the eyes on day 1 postoperatively, which lessened gradually from the 4th day. On day 7, the number of eyes with aqueous flare in each group had no significant difference(P>0.05).4. The changes of intraocular pressureThere was no significant difference between the control group and the 5-Fu groups (F=0.08 P>0.05), The intraocular pressure before and after operative had significant difference (F=85.17 P<0.01), the pressure on postoperative day 1 was significantly higher than that of the second and the third day (P<0.05). The IOP before-operation versus the 2nd and the third day after-operation had no great difference (P>0.05) .5. Clinical Assessment5.1 The number of eyes developing PCO at different time postoperativelyTwo weeks postoperatively, 2 eyes in the control group developed PCO (the score was graded as 1), while the posterior capsule of all the eyes in the 5-Fu group still keep clear (the PCO score was graded as 0); By 1 month, 3 eyes in t...
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