Feasibility study of chitosan as intravitreous tamponade material
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Chitosan can inhibit fibroblastic proliferation by suppressing fibroblast cells, and has the similar physiological characteristics as normal vitreous body, so it might have the potential to become vitreous filling material and might possibly inhibit proliferative vitreous retinopathy. To investigate the possibility of chitosan as vitreous filling material, this study was designed to investigate retina, ciliary body, lens and cornea morphology changes, intraocular pressure and intraocular inflammatory factors fluctuating after chitosan intravitreous tamponade.
Fifteen healthy chinchilla rabbits were chosen; three of them were a blank (negative) control group without any surgical procedure. The remaining 12 rabbits received vitrectomy on both eyes; all the right eyes (experimental group) were given 1.2–1.8 ml (average 1.5 ml) of chitosan intravitreously, while sodium hyaluronate were given in the left eyes (control group). All eyes underwent slit-lamp biomicroscope and indirect ophthalmoscope examination and intraocular pressure measurement pre- and post-op. The concentration of IL-6, IL-8 (radioimmunoassay), NO (nitrate reductase method) in aqueous humor and vitreous body were tested at day 15 and day 30 post-op. At day 30 post-op, the cornea, ciliary body, and lens were dissected for light microscopy examination, and the retinal tissues 2PD away from the optic disc on the vertical orientation of posterior pole were dissected for light- and electro-microscope examination.
The conjunctival congestion and slight inflammatory response in the anterior chamber disappeared within 7 days post-op. During the 30-day experiment, cornea, lens and the filling material in vitreous cavity were transparent in all animals. The retina was attached without proliferation. The intraocular pressure in the experimental group post-op fluctuated between 4.55 ± 2.94 and 6.25 ± 2.37 mmHg, which was not significantly different from the situation pre-op (6.18 ± 1.19 mmHg) (P > 0.05). The intraocular pressure in the control group post-op fluctuated between 5.10 ± 2.51 and 5.90 ± 2.49 mmHg, which was not significantly different from the situation pre-op (6.50 ± 0.94 mmHg) (P > 0.05). There was also no significant difference in the intraocular pressure post-op at different time points between the experimental group and control group (all P > 0.05). At day 15 post-op, IL-6 concentration in aqueous humor were 37.31 ± 8.59 ng/ml and 39.52 ± 9.69 ng/ml in experimental group and control group respectively, both higher than those in the blank control group (26.55 ± 9.34 ng/ml) (P < 0.05). IL-8 concentration were 7.00 ± 3.79 ng/ml and 6.32 ± 3.68 ng/ml respectively, no significant difference to the blank control group (4.72 ± 1.71 ng/ml) (P > 0.05): the concentrations of NO were 63.94 ± 26.80μmol/ml and 51.81 ± 13.19μmol/ml respectively, no significant difference to the blank control group (50.36 ± 15.67μmol/ml) (P > 0.05). At day 30 post-op, the concentrations of IL-6, IL-8 and NO in aqueous humor showed no significant difference among all three groups (P > 0.05). In vitreous body at day 30 post-op, the concentrations of IL-8 in experimental group and control group were 10.17 ± 3.63 ng/ml and 10.69 ± 3.52 ng/ml, and those of NO were 50.23 ± 19.69 μmol/mL and 50.60 ± 12.72 μmol/mL respectively, all higher than in the blank control group (30.37 ± 14.63 μmol/ml) (P < 0.05); the concentrations of IL-6 were 24.51 ± 10.71 ng/ml and 26.36 ± 13.00 ng/ml, no significant difference to the blank control group (24.06 ± 5.98 ng/ml) (P > 0.05). At various time points, there was no significant difference in the concentrations of IL-6, IL-8 and NO in aqueous humor and vitreous body in the experimental group and the control group (P > 0.05). There was no morphological change found under light microscopy in cornea, ciliary body and lens. The outer plexiform layer of retina was thinner, but no significant degeneration, necrosis, karyopyknosis or lysis were found under the ultrastructural microscopy.
Chitosan intravitreous tamponade has no significant effect on the histology of the eye, doesn’t cause intraocular pressure to fluctuate, and slightly increases inflammatory factors (IL-6, IL-8, NO) in comparison to the normal levels, but with no significant difference from the effects caused by sodium hyaluronate, which indicated chitosan might not lead to a clinically significant inflammatory response. It suggests that chitosan could be used as intravitreous tamponade material.
KeywordsChitosan Intraocular tamponade Vitrectomy Tissue structure Inflammatory factor
- 3.Lu F, Huang FW, Sheng YH et al (1993) Manufacture and preliminary study about polysaccharides in exoskeleton as an adjunctive drug after glaucoma filtering surgery II.preliminary study for inhibiting fibroblastic proliferation. J Inj Occup Disease Eye Ophthalmic Surg 15(4):254–255Google Scholar
- 4.Chen JX, Hu P, Li XL et al (2002) Chitosan membrane on nonpenetrating filtering in rabbits. Acad J PLA Postgrad Med Sch 6(2):139–141Google Scholar
- 5.Jiang YY, Jiang ZX, Dai L et al (2002) Study on the prevention of posterior capsular opacification by heparin-chitin drug delivery system. Chin Ophthal Res 20(5):404–406Google Scholar
- 6.Meyer K, Palmer JW (1934) The polysaccharide of the vitreous humor. J Biol Chem 107:629–634Google Scholar
- 7.Li Y, Zhou YQ, Hou CL (1997) Experimental study on the effects of chitosan in intraocular surgery. Acad J Sec Mil Med Univ 18(5):455–457Google Scholar
- 8.Hou CL, Lu JZ, Bao JL et al (1993) Biological characteristic Study of Chitin. Chin J Rep Recon Surg 7(2):115–116Google Scholar
- 12.Michel G, ean-Pierre H, Christian de C et al (1986) The effect of liquid silicone on the rabbit retina: histologic and ultrastructural study. Arch Ophthalmol 104:1057–1062Google Scholar
- 15.Hui YN, Shi YN, Yang G et al (2000) Proinflammatory cytokines in vitreous of experimental PVR model induced by macrophages. J Clin Ophthalmol 8(4):307–310Google Scholar
- 16.Li ZJ, Peng GH (2000) Cytokine and intraocular inflammatory. Rec Adv Ophthalmol 20(3):169Google Scholar
- 17.Chin AM, Hou CL, Chen QQ et al (2002) Comparison study of chitosan and hyaluronate sodium in the treatment of elbow adhesion. Orthop J Chin 10(13):1289–1291Google Scholar
- 18.He JY, Lao J, Gu YD et al (2004) An experimental research of the growth rule of activated Schwann cells cultured on chitosan-collagen film. Orthop Biomech Mater Clin Study 1(4):11–14Google Scholar
- 19.Zhang JD, Xing X, Zhen JX et al (2003) The effects of chitosan on cytokine of scars derived from different fibroblasts. Chin J Clin Rehabil 7(20):2792–2793Google Scholar
- 22.Tllum L, Farraj NF, Davis SS (1994) Chitosan as a novel nasal delivery system for peptide drugs. Pharm Res 11(2):1186Google Scholar