Effect of amiloride to retinal toxicity induced by tissue plasminogen activator.
OBJECTIVE
The effects of amiloride on cellular toxicity caused by tissue plasminogen activator (tPA) in mouse primary retinal cells were investigated.


METHODS
Primary retinal cell cultures were maintained using glial conditioned medium. Commercial tPA and L-arginine were added, and the level of cyclic guanosine monophosphate (cyclic-GMP) in the culture supernatant was assessed using an ELISA assay. We measured the cell viability of cultured retinal cells pretreated with three different concentrations of amiloride (1, 10, and 100 µm) in addition to commercial tPA or L-arginine treatment.


RESULTS
After exposing the cultured mouse retinal cells to tPA plus L-arginine or L-arginine alone, cyclic-GMP concentrations were 61.9 ± 5.1 pmole/mL and 63.1 ± 6.1 pmole/mL, respectively. However, the control group had a significantly lower concentration of cyclic-GMP (37.2 ± 3.4 pmole/mL, p < 0.01). The cyclic GMP-dissolved solution did not cause retinal cell death. In the control group and the group treated with 1 µm amiloride and tPA containing L-arginine, the cell viability was 43.7% and 44.5%, respectively. However, cell viability increased to 70.6% with 10 µm amiloride and 78.4% with 100 µm amiloride (p = 0.015).


CONCLUSIONS
L-arginine increases intracellular cyclic-GMP and may give rise to retinal cells through this mechanism. In addition, amiloride in concentrations greater than 10 µm protects against L-arginine-induced retinal cell death.
Department of Ophthalmology, Kim's Eye Hospital, Konyang University College of Medicine, Seoul, Korea.
Ungsoo Samuel
US
Kim
Hyun-Sub
HS
Oh
Oh Woong
OW
Kwon
In
I
Chung
Sung-Ho
SH
Lee
Joon Haeng
JH
Lee
D000584:Amiloride / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000633:toxicity; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D012160:Retina / Q000166:cytology / Q000187:drug effects*; D010959:Tissue Plasminogen Activator / Q000633:toxicity*
D000584:Amiloride; D001120:Arginine; D010959:Tissue Plasminogen Activator; D006152:Cyclic GMP