| In recent years, most ophthalmologists have realized that the abnormal vitreoretinal junction is the pathologic foundation of numerous vitreoretinal diseases. So the reasonable cleavage of the vitreoretinal adhesion is very helpful in the treatment of these diseases. Pars plana vitrectomy is the most efficient method, but to those who have firmly vitreoretinal adhesion, it can not remove the cortex completely and often cause some complications. So various pharmacologic adjuncts have been used to induce posterior vitreous detachment, these adjuncts can help even replace the vitrectomy. In addition, artificial induction of PVD in the present-day later vitrectomy surgery can greatly shorten the time. At the same time reducing the mechanical operation of traction caused by iatrogenic retinal breaks, the incidence. In particular, young patients can greatly reduce the possibility of iatrogenic retinal breaks, and even further can replace surgery. Proliferative vitreoretinopathy (PVR) is a traumatic eye after vitrectomy common complications, such as can be induced by preoperative artificial PVD can greatly reduce the complications. For these many reasons, the drug-PVD importance to the Experimental Study.Clinically, an inert perfluoropropane gas (C3F8) as retinal surgery and intraocular stuffing into the vitreous cavity. C3F8 gas with non-toxic, chemically stable characteristics of the glass to absorb the body tissue of oxygen, nitrogen, carbon dioxide and other gases and the expansion may be the formation of 2-5 times the original size of the larger air mass. Alternative to animal experiments have been vitrectomy the vitreous cavity of a larger, and hence is known as gas vitrectomy. At the same time, C3F8 retinal function of very small, is already widely used in clinical.This study in rabbits injected with C3F8 gas in different size observed in the vitreous cavity of C3F8 on the role of vitreous liquefaction and PVD induced at the same time observed in the vitreous cavity C3F8 security.Materials and Methods1. Animal model building: 24 cleaning New Zeal rabbits were randomized into A,B,C and D 4 groups, 6 in in each group respectively. Right eyes as the experimental groups, left eyes as control group. Given degermation air 0.1ml into group A, The other experimental groups were given perfluoropropane 0.1ml(group B), 0.2ml(group C), 0.3ml(group D) after adopt punctute of anterior chamber to draw part aqueous fluid. balanced salt solution (BSS) were injected into left eyes as control.2. The information of perfluoropropane vitreous cavity injection induced posterior vitreous detachment: using B scan to observe vitreous body; 8w sacrificed rabbits , at the same time the globes were processed for scaning electron microscopy(SEM) to determine the state of posterior vitreous cortex and internal limiting membrane.3. The degree of perfluoropropane vitreous cavity injection induced posterior vitreous detachment: removal eye protomcrition , then the retina of globes were divided an area of 1mm~2 into the posterior pole parts, the supra ambitus and inferior ambitus. The same time the globes were processed for scaning electron microscopy(SEM) to determine the state of posterior vitreous cortex and internal limiting membrane.4. The evaluate the toxicity of perfluoropropane: Examined electroretinogram every day in the first week then every weeks; The globes were enucleated and examind with transmission electronic microscope(TEM) and light microscope to observe the state and the ultramicro-structure of the retina. Results1. Animal model were found. Experimental groups have different degree fliud vitreous except A group. It is clear that uneven cloudiness muddy can been seen in gas absorption prcess. Cloudiness disappeared after gas absorption in B group.2. Observed from B scan, experimental group have different degree fluid vitreous except A group. Some eyes in group C and group D showed separation of the vitreous cortex from retina. It showed complete PVD in D group after operation for 8w.3. Scaning electron microscopy(SEM) showed, control group, A group and B group without PVD happened, C group and D group had definite PVD.4. The differences among the different parts in the same dose group had statistic singnficance (the posterior parts was strongest place). Meanwhile the differences among the different dose of perfluoropropane in the same parts had statistic significance(0.3ml was strongest).5. Compared ERG before operation, both A,B wave amplitude and A,B wave implicit time were normal. Only D group had A,B wave amplitude breakdown meanwhile A,B wave implicit time delayed.6. Light microscope had displayed that the structures of retina were integrated and there were not exicted any abnormal changes in groups. transmission electronic microscope(TEM) had displayed that the structure of the internal limiting membrane integrated in both experimental group and control group.Conclusions1. Intravitreal injection of perfluoropropane can induce PVD. Tiny air bubble cancause fluid vitreous in a short time without PVD appear.2. The differences among the different parts in the same dose group had statisticsingnficance (the posterior parts was strongest place). Meanwhile the differences among the different dose of perfluoropropane in the same parts had statistic significance(0.3ml was strongest). 3. Intravitreal injection of perfluoropropane in rabbits foundmental without the toxicity between 0.1ml to 0.3ml.4. 0.2ml perfluoropropane was the reasonable and safe dose in this experiment. |
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