Pharmacologic vitreolysis with plasmin and hyaluronidase in diabetic rats.
OBJECTIVE
To evaluate the feasibility of inducing posterior vitreous detachment (PVD) with pharmacologic vitreolysis in diabetic rats.


METHODS
Forty diabetic rats were randomly divided into four groups and treated with different drugs by intravitreous injection respectively as follows: Group A: hyaluronidase (5 U); Group B: plasmin (0.25 U); Group C: hyaluronidase (5 U) plus plasmin (0.25 U); and Group D: balanced salt solution (2 microL). Ten normal rats in Group E were used as controls and were treated with hyaluronidase (5 U) plus plasmin (0.25 U). Clinical observation, visual electrophysiology tests (electroretinogram), transmission electron microscopy, and scanning electron microscopy were performed on the rats 1 week after the injection.


RESULTS
Scanning electron microscopy results showed that PVD did not occur at all with hyaluronidase alone (Group A, 0 of 10) and balanced salt solution alone (Group D, 0 of 10). Partial PVD was found in all eyes treated with plasmin alone (Group B, 10 of 10), whereas complete PVD was present in most but not all eyes treated with both hyaluronidase and plasmin (Group C, 8 of 10). All nondiabetic eyes treated with hyaluronidase and plasmin had total PVD (Group E, 10 of 10). No significant difference in electroretinogram was observed in each group before and after the injection (P < 0.05).


CONCLUSIONS
Hyaluronidase (5 U) alone is ineffective, whereas plasmin (0.25 U) alone induces partial PVD, a very dangerous state for the diabetic eye. Combination of hyaluronidase and plasmin can induce complete PVD in 12-week old diabetic rats. However, it is more difficult to induce PVD in diabetic rats than in healthy rats. No obvious toxic reaction was observed in each group.
Zhi-Liang
Wang
W
Department of Ophthalmology, Shanghai 9th People's Hospital, Medical School of Jiao Tong University, Shanghai, China.
Wo-Dong
Shi
S
Min
Luo
L
Xiao-Ping
Bi
B
Jin
Ji
J
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D003921:Diabetes Mellitus, Experimental / Q000150:complications; D003930:Diabetic Retinopathy / Q000150:complications*; D004359:Drug Therapy, Combination; D004596:Electroretinography; D005341:Fibrinolysin / Q000494:pharmacology*; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology*; D007267:Injections; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000502:physiology; D014822:Vitreous Body / Q000187:drug effects* / Q000648:ultrastructure; D020255:Vitreous Detachment / Q000139:chemically induced*
D005343:Fibrinolytic Agents; D006821:Hyaluronoglucosaminidase; D005341:Fibrinolysin