Effect On The Chitosan Drug Deliver System Implanting Into Suprachoroidal Space On Perforating Ocular Injury In Rabbits

Vitreous opacification and detachment of retina are always serious in perforating injury eyes. In recent 20 years, part of patients have got effective treatment and reserve part of acuity of vision by vitrectomy with this operation being applied. The achievement ratio of vitrectomy is related to the degree of injury of vitreous body, vascular coat of eyeball uvea and retina. The refined debride and suturation and the application of adrenal cortex hormone can reduce the degree of injury of vitreous body, vascular coat of eyeball uvea and retina after perforating injury of eyeball. And the applied method of adrenal cortex hormone is a topic worth being discussed.The therapeutic effects of drug on ocular perforating injury are not satisfied in most of suffers. Large dose of drugs are often used with much side effect and with other question, such as rebound, in system administration. On the other hand, the later therapy effect, bother drop, hurt the global tissue and toxicity of retinal limit the application of topical administration in common using. According to this situation, mending the way of administration will keep the virtue of original administrations and get the better effects with the tradition drugs.The perichoroidal space is a potential lacuna with abundant blood vessels between sclerotic coat and choroids. Drugs can be absorbed fast in this location which posses stronger endurance than retinal. We design and produce chitosan drugdeliver system (with triamcinolone acetonide in it) and implant it into epichoroidal space on perforating ocular injury in rabbits to observed its therapeutic effect by comparising the pathological change of vitreous body, vascular coat of eyeball uvea and retina.Chitosan is product of chitin which is being taken off part ethanoyLThe preparative method of chitosan is simple . We can gain it from shrimp or mitten crab carapace by pickling and decalcification after emundation and deproteinization by using 10% lye, and then de-ethanoyl by strong alkali continuely.lt has been more than 100 years after chitosan being found .It is more and more important because it has galactic latent application value and extensive developing perspective in the domain of biotechnology, medicine biomedicine engineering. In the domain of medicine, chitosan is a sort of neotype of biomaterial. It has satisfactory histocompatibility and harmful biology degradation body. It can regulate immunologic function and promote tissue repairment, inhibit fibrocyte growth, prevent organization adherence adjust cholesteryl metabolism, and possess the function of hematischesis and bacteriostatic action.Triamcinolone acetonide (TA), which applied generally by intravitreous injection to treat proliferative vitreoretinopathy is a prolonged action corticoid. Triamcinolone acetonide has below pharmacological action: 1. anti-inflammatory effect, 2. anti-fibrosis and anti-scarification, 3. immunosuppressive action. Triamcinolone acetonide is used in ophthalmologic domain because of its notable anti-inflammatory, anti-fibrosis, anti-scarification,and immunosuppressive action. Local application in eyes rarely has harmful effects on hematopoietic system, central nervous system and digestive system.Objective To compare the therapeutic effects of suprachoroidcavity drug administration with those of other topical administrations on treating ocular perforating injury. To evaluate the effect of suprachoroidcavity drug administration.Methods: 1. All the24 normal pigment rabbits were divided into two groupsrandomly: A,B, After all eyes suffered perforating injury, chitosan drug deliver system with lmg triamcinolone acetonide was implanted into suprachoroid in A group and lmg was injected into conjunctiva in B group. The effect was measured by the grade of retinal detachment -> vitreous body opacitas> FFA and histopathology.The method of the ranking of the retinal detachment: grade 0: ocular fundus is normal, no vitreous opacification, grade 1: ocular fundus is normal, proliferative strap can be seen in the vitreous body; grade 2: strap can be drag to medullary ray, or local retinal detachment can be seen, grade 3: retinal detachment completely or funnel-shaped detachment o We add up grade 2 and grade 3 to the incidence rate of retinal detachment. The method of the ranking of the vitreous opacification: grade 0: there is no vitreous opacification in ocular fundus, grade 1: vitreous opacification is light ,and ocular fundus can be seen, grade 2: vitreous opacification is midrange ,and ocular fundus can be seen permeate vitreous opacification, strap can be drag to medullary ray, or local retinal detachment can be seen grade 3: vitreous opacification is severe, and ocular fundus can not be seen completely. We add up grade 2 and grade 3 to the incidence rate of proliferative vitreousResults: The effect of suprachoroidcavity drug administration is superior to those of other administrations on treating ocular perforating injury. 1. Operative incision in every rabbit heal well, group A has none perichoroidal space hemorrhoea and complication of detachment of retina, group B has conjunctival ulcer and necrosis in one case at Injection site. 2. The ranking of retinal detachment demonstrate group A is no more severe than group B. In group A the ranking of the retinal detachment, 8 eyes in grade 0, 12 eyes in grade 1, 2 eyes in grade 2, 2 eyes in grade 3. In group B the ranking of the retinal detachment, 0 eyes in rade 0, 8 eyes in grade 1,12 eyes in grade 2,4eyes in grade 3.3. The ranking of vitreous opacification demonstrates group A is no more severe than group B. In group A the ranking of vitreous opacification, 7 eyes in grade 0,10 eyes in grade 1, 4 eyes in grade 2, 3 eyes in grade 3. In group B the ranking of vitreous opacification, 1 eyes in grade 0, 7 eyesin grade 1, 9 eyes in grade 2, 7 eyes in grade 3. 4. patho-organization section demonstrate group A is no more severe than group B.5. FFA examine group A has no blocked fluorescence, the fundus of eye is clear, The district of administration fluorescent light is normal. In group B, vitreous opacification is more heavy, blocked fluorescence can be seen .In vicinity of wound, fluorescein leak out of blood vessel .The therapeutic effects of chitosan drug deliver system implanting into epichoroidal space on Perforating Ocular Injury in Rabbits is superior to the administration of subconjunctival injection.Conclusion: The suprachoroidcavity drug administration is safe and effective and provides a new choice on treating ocular perforating injury.