| The purpose of drug treatment for glaucoma is to reduce intraocular pressure by reducing the production of aqueous humor and promoting the outflow of aqueous humor, in order to inhibit the progression of the disease. The drawback of traditional ophthalmic administration is that the drug administered has short duration of action and requires frequent usage. In order to explore more effective treatment of glaucoma, this experiment used different materials to induce glaucoma in a rabbit model through clinical and histological observation to find out the most efficient method, by applying Peurarin-containing contact lenses on subject rabbit and ophthalmic administration of puerarin-containing eye drop and pilocarpine-containing eye drop to assess the clinical efficacy of those three methods via observing clinical signs of the ocular surface of rabbits and histological changes of the anterior chamber.(1) The model building of rabbit glaucoma:Firstly,12 healthy rabbits free of ocular disease were selected and randomly divided into four groups (n=5):M20 group, M450 group, MCH group and C940 group. Methylcellulose M20, methyl cellulose M450, methylcellulose MCH and Carbopol C940 compound were applied respectively in those four groups for building the glaucoma model. Intraocular pressure were measured 2h,4h,8h,12h,24h,48h,96h,192h, 384h after the operation and cornea turbidity and neovascularization was graded on day 3, day 6, day 12 and day 18. On day 18, all subjects were euthanized and the eye balls removed for histopathological examination. Test results are as follows:The Intraocular pressure of all four groups were significantly higher than pre-operative levels. There were varying degrees of complications i.e. corneal edema, corneal opacity and corneoscleral congestion. The complications of group M20 and M450 were relatively mild with short-term persistence and the intraocular pressure of M20 and M450 group dropped to normal levels 4h and 8h after operation; MCH and C940 group had more severe complications which persisted for a longer period of time, which indicates significant differences compared with M20 and M450 group (P<0.01). Neovascularization occurred on the corneal surface; C940 group had more severe complications than group MHC, bean-sized blisters were found on the corneal surface on day 3, neovascularization extended to the central area of the cornea and formed pannus.Microscopic examination of rabbit anterior chamber section (HE staining):In M450 group and M20 group, there was mild stenosis of Schlemm tubules in the anterior chamber angle; irregular shape of trabecular meshwork and narrowed inter-trabecular space; In MCH Group, there was blockage in the lumens of Schlemm tubules in the anterior chamber angle, trabecular fibrosis and adhesions to the iris, the disappearance of endothelial cells and the meshwork structure; the atrophy of iris including the fibrosis of its stroma; In C940 group, the occlusion of the Schlemm tubules of the anterior chamber angle, severe trabecular fibrosis, the disappearance of endothelial cellular and meshwork structure; the thickening of iris and fibrosis of iridal stroma which result in the adhesion to the trabecula were observed.From the result above, MHC-based glaucoma model has more stable intraocular pressure, longer duration of maintenance, and the pathological changes of anterior chamber angle were in accordance with the characteristics of glaucoma. It is more suitable for applications in studying the pathophysiological changes of chronic glaucoma, compared with Carbopol C940.(2) The therapeutic experiment of puerarin-containing contact lenses treatment for rabbit glaucoma model:20 healthy rabbits free of ocular disease were selected, and were injected with 2% 0.2 mL methylcellulose-HV into anterior chamber of right eyes to induce glaucoma model. And then randomly divided into four groups (n= 5), the control group wore drug-free contact lenses for 12hr per day, PCL group wore puerarin containing contact lenses for 12hr per day; Pue group and Pilo group were ophthalmically administered with Puerarin and pilocarpine eye drops respectively, twice per day at 6hr intervals. Intraocular pressure, the degrees of corneal opacity and the condition of neovascularization on day 0, day 7, day 14, day 21, day 28 and day 35 was observed, recorded and graded. All rabbits were euthanized on day 35, and their eyeballs were removed for histopathological observation. Test results are as followsThe intraocular pressure of the control group continued to rise. Intraocular pressure in the control group significantly higher than Pue group (P<0.05), and extremely significantly higher than PCL group and Pilo group (P<0.01) in the first 21d. On day 28 to day 35, the intraocular pressure of control group was significantly higher than other three treatment groups (.P<0.01). After treatment, the intraocular pressure of PCL group, Pue group and Pilo group dropped to normal range on day 7, day 14 and day 21 respectively and no significant difference was present between the 3 treatment groups. In the control group, the corneal opacity gradually increased from 7d to 35d with neovascularization extending to the central area of the cornea. In PCL group, 7 days after treatment, neovascularization ceased and began to resolve, on day 14, corneal opacity began to recede gradually, corneal opacity score and corneal neovascularization score were significantly lower than the preoperative level on 35d (P<0.01); PCL group and Pilo group had minor differences in pathological changes of the ocular surface, no significant difference when compared with Pue group.Microscopic examination of rabbit anterior chamber section (HE staining):the blockage of Schelmm tubules, trabecular meshwork fibrosis with extensive adhesion to iris, and the disappearance of meshwork structure, the shedding of endothelial cells and thickening and fibrosis of iris were found in control group. In PCL group, there was stenosis of schelmm tubules with the infiltration of leukocytes in the lumen, the widening of the inter-trabecular space infiltrated with leukocytes. In Pue group, there was stenosis of schelmm tubules with the infiltration of leukocytes in the lumen, the narrowing and fibrosis of trabecular meshwork and rupture of some of trabeculae. In Pilo group, the stenosis of schelmm tubules, parital fibrosis of trabecular meshwork, the expansion of the lumen and infiltration of leukocytes was observed.On the basis of results above, puerarin-containing contact lenses can effectively reduce the intraocular pressure of rabbits, inhibit the inflammation process and neovascularization; there was an significant improvement on the treatment effect of releasing intraocular pressure but no significant difference on the treatment of its complications when compared with puerarin eye drop. |
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