Using computerized vitreous fluorophotometry (VFP, Fluorotron(TM)), we examined the effect of cryotherapy on the blood retinal barrier (BRB) and the effect of subtenon injection of methylprednisolone acetate (Depomedrol(R)). In experiment 1, the right eyes of the 13 pigmented rabbits were treated with heavy cryotherapy after baseline VFP readings. The freezes were applied at 6 places in each quadrant around the equator are in two rows, a total of 24 places circumferentially. The left eyes were reserved as controls. In 6 rabbits (cryo with steroid group), Depomedrol(R) 10 mg of Depomedrol was injected into subtenon space after cryotherapy. The other 7 rabbits were treated with cryotherapy only (cryo only group). The VFP readings were taken 1, 3, 5, and 7 days, 2, 3, 5, and 7 weeks after cryotherapy. Cryotherapy increased the breakdown of BRB significantly. The peak VFP readings were obtained 5 days after cryotherapy in the cryo only group and 7 days after cryotherapy in the cryo with steroid group. In the cryo only group, the severity of the breakdown of BRB was higher than in the cryo with steroid group, and the increased VFP readings could not be normalized until 7 weeks after cryotherapy. In experiment 2, both eyes of the 8 pigmented rabbits were treated with medium cryotherapy after baseline VFP readings. The freezes were applied at 3 places in the superior temporal quadrant and at 3 places in the superior nasal quadrant, a total of 6 places. Depomedrol(R) 10 mg was injected into subtenon space after cryotherapy in the right eyes only. The VFP readings were taken 1, 3, 5, 7, 10, and 14 days after cryotherapy. In this experiment, cryotherapy did not increase the breakdown of BRB. But in the right eye, the severity of the breakdown of BRB was significantly lower than in the left eye 7 and 10 days after cryotherapy. These results suggest that Depomedrol(R) can decrease the severity of the breakdown of BRB after cryotherapy, and may be useful in the prevention of proliferative vitreoretinopathy (PVR).
Animals ; Anti-Inflammatory Agents/*pharmacology ; Blood-Retinal Barrier/*drug effects ; Capillary Permeability ; *Cryosurgery/adverse effects ; Fascia ; Fluorophotometry ; Injections ; Methylprednisolone/*analogs & derivatives/pharmacology ; Orbit ; Rabbits ; Retina/*drug effects/surgery ; Vitreoretinopathy, Proliferative/prevention & control

OBJECTIVE: To demonstrate the mechanism of positive effects of the sequential air-fluid exchange on the use of complicated vitroretinal microsurgery. METHODS: Seventy-one patients who underwent vitreoretinal microsurgery were performed 2 or 3 times sequential air-fluid exchange. The regenerated fliud in vitreous cavity at various periods was collected to act on cultured human retinal pigment epithelial (RPE) cells,and then the secretion of bFGF and the expressions of bcl-2 and ki-67 by RPE cells were observed. RESULTS: The expressions of bcl-2 and ki-67 were up-regulated and the secretion of bFGF significantly increased after RPE cells was acted with the regenerated fluid in the vitreous cavity. CONCLUSION The sequential air-fluid exchange can mechanically reduce intraocular growth factors after the vitreoretinal microsurgery, indirectly restrain the proliferation of RPE cell, and improve the successful rate of vitreoretinal microsurgery.
Cell Division ; Cells, Cultured ; Fibroblast Growth Factor 2 ; metabolism ; Humans ; Ki-67 Antigen ; biosynthesis ; genetics ; Microsurgery ; Pigment Epithelium of Eye ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; Regeneration ; Retina ; surgery ; Retinal Detachment ; prevention & control ; Secondary Prevention ; Vitrectomy ; Vitreoretinopathy, Proliferative ; surgery