[A study of vitreous liquefaction using in vitro models--1. The effect of plasma on vitreous liquefaction].

To study the mechanism of vitreous liquefaction following vitreous hemorrhage, an in vitro study was done. We isolated whole vitreous gel of pig eyes, then weighed, incubated it with sample solution and shook it at room temperature. The ratio of weight loss after shaking to initial weight were calculated as vitreous liquefaction rate (VLR). There was no significant difference in VLR between samples incubated with whole blood (50.7%) and with plasma (48.8%), and it was significantly higher than control incubated with isotonic phosphate buffered physiological saline (PBS)(14.8%) after 24 hours shaking. There were no significant differences between control and samples incubated with blood cells (21.1%) and with hemoglobin (20.5%). The VLR of samples incubated with plasma gradually increased with time whereas controls incubated with PBS showed no changes until 24 hours. The VLR and concentration of plasma were highly correlated. These results indicated that contact of plasma with vitreous gel encourages liquefaction possibly by enzymatic digestive action with proteases.