Porcine model of proliferative vitreoretinopathy with platelets

To develop an experimental model of proliferative vitreoretinopathy (PVR) in the pig, and determine the efficacy of platelet-derived growth factor (PDGF) compared with different platelet plasma concentrates in its development.

Animals were divided into four groups of 12 pigs each. Group 1, 2, and 3 underwent four 3-mm-long retinotomies, a partial mechanical vitrectomy, and six transconjunctival retinal cryoapplications and were injected intravitreally with, respectively, 0.2 ml of platelet rich plasma, 0.2 ml of a solution containing 200 ng of porcine PDGF, and 0.2 ml of platelet concentrated plasma. Group 4 received only an intravitreal injection of 0.2 ml of porcine PDGF.

In Group 1, retinal detachments (RDs) developed in six eyes (50%) (two eyes, total RDs; four, extensive RDs). In Group 2, focal RDs developed in six eyes (50%). In 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 found 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 retinal holes with rolled edges were observed.

We have developed a model of PVR in the pig, the retina of which more closely resembles that of humans. Platelet plasma more effectively contributed to the development of an experimental model of porcine PVR than 200 ng of PDGF. The efficacy depends on the platelet concentration of the plasma. These results suggest that other growth factors and plasma components may interact synergistically with PDGF in the pathogenesis of PVR.