PORCINE MODEL OF PROLIFERATIVE VITREORETINOPATHY WITH PLATELETS

Purpose. To develop an experimental model of proliferative vitreoretin opathy (PVR) in the pig, and determine the efficacy of platelet-derive d growth factor (PDGF) compared with different platelet plasma concent rates in its development. Methods. Animals were divided into four grou ps of 12 pigs each. Groups 1, 2, and 3 underwent four 3-mm-long retino tomies, a partial mechanical vitrectomy, and six transconjunctival ret inal cryoapplications and were injected intravitreally with, respectiv ely, 0.2 ml of platelet rich plasma, 0.2 ml of a solution containing 2 00 ng of porcine PDGF and 0.2 ml of platelet concentrated plasma. Grou p 4 received only an intravitreal injection of 0.2 ml of porcine PDGF. Results. In Group 1, retinal detachments (RDs) developed in six eyes (50%) (two eyes, total RDs; four, extensive RDs). In Group 2, focal RD s developed in six eyes (50%). Tn Group 3, 11 eyes (92%) developed Rds (six eyes, total RDs; three, extensive RDs, two, focal RDs). Group 4, did not develop lesions. Statistically significant differences were f ound between Group 3 and the other groups. Group 2 RDs were associated with the presence of vitreoretinal membranes but there were no signs of PVR. In Groups 1 and 3, signs of anterior PVR, posterior PVR, and r etinal holes with rolled edges were observed. Conclusions. We have dev eloped a model of PVR in the pig, the retina of which more closely res embles that of humans. Platelet plasma more effectively contributed to the development of an experimental model of porcine PVR than 200 ng o f PDGF The efficacy depends on the platelet concentration of the plasm a. These results suggest that other growth factors and plasma componen ts may interact synergistically with PDGF in the pathogenesis of PVR.