The Effect On Posterior Scleral Reinforcement Of Experimental Rabbits With Periorbitally Injecting Chitosan Glycerophosphate Disodium

Objective:To discuss the effect on posterior scleral reinforcement of experimental rabbits with periorbitally injecting chitosan glycerophosphate disodium.Method:1 selected 20 rabbits, male and female in half, weight 2-2.5kg, were randomly selected five rabbits : the blank control group;the remaining rabbits were ( The left eye of treatment group rabbits were surgical eye.)Extraocular disinfection with 2% lidocaine retrobulbar anesthesia, 2% tetracaine surface anesthesia; injection needle were curved extraocular injection needle with consistent with the curvature of the eye. Open eyelid device opened eyelid . Conjunctival were dished with non-tooth forceps above the eye from the temporal limbus 3mm.We cut 1mm small incision with scalpel,peeled fascia exposed porcelain white sclera surface, blunt needle was entangled with syringe, needled along incision. Along fascia space , closing to the sclera, needled to the backward 3mm- 4mm,injected chitosan glycerophosphate disodium1.2mm-1.5mm, suture conjunctival,fascia and superficial sclera,then massaged eyeball,made drug evenly distributed periorbital.After the surgery, gentamicin injection and dexamethasone injection washed conjunctival sac, smeared erythromycin eye ointment, wrap the surgical eye.2 After surgery,we observed normal activities, regular diet of rabbits in the first 4h, 24h, 48h, 72h .Observe all experimental animals, movement times, difficulty breathing and eye irritation. Measuring experimental animals 0h, 24h, 48h, 72h before eating, calculate weight change per day.3 After surgery 2w,4w,6w,8w measure IOP, FFA, CT, A/B -ultrasonography. Rabbits were killed by injecting air embolism in ear vein, injected gentian violet 0.2ml cavity under the fascia of surgical eye, massaged eyeball,made gentian violet liquid and chitosan glycerophosphate disodium mixed fully.After frozen rabbit head 12h, along rabbits orbital made coronal section and sagittal Section with self-made small saw blade,the rest rabbits were removed eyeball,washed clean, Mixed scleral tissue was cut, the naked eye observed firstly,then fixed with 10%formalin respectively, used paraffin-embedded,slice,HE staining,light microscope observed.Results:1 C / GP biocompatibility: periorbital injection of C / GP eye caused mild inflammatory response. Weight changes of groups comparation were no significant difference (P> 0.05).2 intraocular pressure measurement results: After 2 weeks, 4 weeks, 8 weeks, compared between 2 weeks group and the control group, there is no statistical difference in the left eye IOP (P> 0.05).With the control group,intraocular pressure of 4 weeks, 8 weeks increased,and the two groups were statistical difference (P <0.05).Compared with 2 weeks, intraocular pressure of 8-week group increased, were statistically significant difference (P <0.05). Compared with 4 weeks, intraocular pressure of 8-week group increased, existed statistically significant difference (P <0.05).Comperaion of 2,4,8 weeks , the right eye of the three groups were not statistically significant compared intraocular pressure (P >0.05).3 axial length measurements: Compared with the control group , axial length of operation groups were no significant difference (P> 0.05). Compared with axial length of the left eye of rabbits in 2,4,8 weeks were no significant difference (P> 0.05), compared with axial length of the right eye of rabbits in 2,4,8 weeks were no significant difference (P> 0.05), left and right eye of rabbits in 2,4,8 weeks were no significant difference between axial (P> 0.05).4 orbital CT examination results: Compared with left eye of control group ,sclera of left eye over the posterior pole partial temporal of rabbits in 2 weeks were significant thickening, formed a annular"new sclera", the new sclera was uniform density, was roughly the same density with the sclera, lowered than the orbital bone density.C/GP integrated with the sclera, and cleared space around the eyes, optic nerve cleared and structured.5 B-ultrasonography test results: After surgical 2 weeks showed :back of the eye above the posterior temporal of left eye in surgical control group had irregular hypoechoic area , After surgical 4 weeks the hypoechoic area had changed into a crescent-shaped hyperechoic area. After surgical 8 weeks the hyperechoic area had weaked, posterior echo had becomed uniform, no abnormal echo in the vitreous body, echo s of retina tructured , optic nerve echo structured, orbital no abnormal echo.6 Frozen section results of the eyeball: After surgical 8 weeks , frozen section of the eyeball shown: Crystal violet staining tissue uniformly attached on the posterior scleral,and integrated with the sclera, and had a clear boundaries with the surrounding tissue space.7 Histopathological observation results: After surgical 2 weeks shown:scleral surface of the uneven thickness of collagen fibers arranged, inflammatory cells had increased , Neovascularization had regenerated. After surgical 4 weeks shown: Scleral surface of granulation tissue had regenerated, neovascularization had regenerated, scleral collagen fibers had thicken and ranged regularly.Granulation tissue had regenerated, Scleral had thicken. 8 Observation results of fundus fluorescein angiography:In the control group and test group had no significant change in fundus fluorescein angiography .Conclusion:1 periorbitally injecting of C / GP did not cause that the rabbits reflect systemic poisoning,however,could cause mild inflammatory response.The inflammatory response of chitosan glycerophosphate disodium in eyeball,it had a good biocompatibility,it could become a scleral reinforcement of a new material.2 At different time points after surgical measured the results of intraocular pressure and axial length ,statistical analysis, with the observation period change, intraocular pressure of experimental group rabbits were increased more than control group, axial length of rabbits were no changed. The change of axial length, to some extent, could reflect the mechanical changes in the eye wall.periorbitally injecting chitosan glycerophosphate disodium had changed sclera of the hardness and elasticity,but it had little effects on the axial length .3 Through the eyeballs of frozen after surgical coronal and Sagittal plane observation, B-ultrasonography and CT of orbital,we fund that the mixture of chitosan glycerophosphate disodium periorbitally injected,it could evenly distributed in the ball after the sclera, closely attached with the sclera, supported the posterior.4 By fundus fluorescein angiography and histopathological observation of scleral,we had fund that periorbitally injecting chitosan glycerophosphate disodium had no effect on the retina, choroid, vitreous body; after chitosan glycerophosphate disodium had integated with the sclera, inflammatory response occurred, neovascularization had regenerated and granulation tissue regenerated, collagen fibers had thicken and ranged regularly, sclera reformed.