Safety and efficacy of dispase and plasmin in pharmacologic vitreolysis.
OBJECTIVE
To evaluate the safety and efficacy of dispase and plasmin when inducing posterior vitreous detachment (PVD) by intravitreous injection in rabbit eyes.


METHODS
Forty-eight young pigmented rabbits were randomized into six groups. Groups 1 and 5 received 0.025 U dispase in test eyes; group 2, 0.1 U dispase; groups 3 and 6, 1 U plasmin; and group 4, 4 U plasmin. All groups received PBS in control eyes. Groups 5 and 6 were euthanatized 15 minutes after surgery for ocular histologic examination. The remaining groups (groups 1-4) received indirect ophthalmoscope and biomicroscopy 15 and 30 minutes; 1, 2, and 8 hours; and 1, 3, and 7 days after surgery. Ultrasonography and electroretinogram were performed 1 hour and 1 and 7 days after surgery. The eyes then were examined by scanning and transmission electron microscopy.


RESULTS
Partial or complete PVDs were observed in the eyes that received dispase and plasmin, confirmed by the results of scanning electron microscopy. Light microscopy showed inflammation in both dispase- and plasmin-treated eyes of groups 5 and 6. However, whereas in plasmin-treated eyes the ERG and cell ultrastructure showed no significant changes, in dispase-treated eyes, the amplitudes of ERG showed a significant reduction from baseline and ultrastructural damage to the retina was detected by transmission electron microscopy. Cell damage, preretinal hemorrhage, and cataract were also observed in these eyes. No changes were observed in the control eyes.


CONCLUSIONS
Intravitreal injection of dispase at 0.025 U or more can induce PVD, but it is not safe. Plasmin (1-4 U) is safer, except for the potential risk of inducing intraocular inflammation.
Department of Ophthalmology, Shanghai First People's Hospital, Shanghai, People's Republic of China.
Fenghua
F
Wang
Zhiliang
Z
Wang
Xiaodong
X
Sun
Fang
F
Wang
Xun
X
Xu
Xi
X
Zhang
D000818:Animals; D002386:Cataract / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D004596:Electroretinography; D010450:Endopeptidases / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology*; D009877:Endophthalmitis / Q000139:chemically induced; D005341:Fibrinolysin / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology*; D005654:Fundus Oculi; D007267:Injections; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D011897:Random Allocation; D012166:Retinal Hemorrhage / Q000139:chemically induced; D014463:Ultrasonography; D014822:Vitreous Body / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000473:pathology
D010450:Endopeptidases; D005341:Fibrinolysin; C023139:dispase