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Effect of amiloride to retinal toxicity induced by tissue plasminogen activator
Ungsoo Samuel Kim1, Hyun-Sub Oh, Oh Woong Kwon
1Department of Ophthalmology, Kim's Eye Hospital, Konyang University College of Medicine, Seoul, Korea.
Purpose:
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.
Insights
Amiloride protects retinal cells from toxicity. Higher concentrations of amiloride (greater than 10 µm) significantly increased cell viability, suggesting a protective role against L-arginine-induced cell death.
Area of Science:
- Ophthalmology
- Neuroscience
- Pharmacology
Background:
- Tissue plasminogen activator (tPA) can induce cellular toxicity in retinal cells.
- L-arginine has been implicated in cellular signaling pathways, including the increase of cyclic guanosine monophosphate (cyclic-GMP).
- Understanding protective mechanisms against retinal cell death is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the effects of amiloride on tissue plasminogen activator (tPA)-induced cellular toxicity in mouse primary retinal cells.
- To determine if amiloride can mitigate L-arginine-induced retinal cell death.
- To assess the role of cyclic-GMP in these cellular processes.
Main Methods:
- Primary mouse retinal cells were cultured and treated with tPA and/or L-arginine.
- Cyclic-GMP levels were measured using an ELISA assay.
- Cell viability was assessed after pretreatment with varying concentrations of amiloride (1, 10, and 100 µm).
Main Results:
- L-arginine treatment, with or without tPA, significantly increased cyclic-GMP levels compared to controls.
- Amiloride at concentrations of 10 µm and 100 µm significantly increased retinal cell viability.
- Cell viability increased from 43.7% in controls to 70.6% and 78.4% with 10 µm and 100 µm amiloride, respectively.
Conclusions:
- L-arginine increases intracellular cyclic-GMP, potentially contributing to retinal cell function or toxicity.
- Amiloride, particularly at concentrations above 10 µm, demonstrates a protective effect against L-arginine-induced retinal cell death.
- These findings suggest amiloride as a potential therapeutic agent for retinal conditions involving L-arginine-mediated toxicity.
