Abstract
Amiodarone (AM) is a potent antidysrhythmic agent that can cause potentially life-threatening pulmonary fibrosis, and N-desethylamiodarone (DEA), an AM metabolite, may contribute to AM toxicity. Apoptotic cell death in nontransformed human peripheral lung epithelial 1A (HPL1A) cells was assessed by annexin V-fluorescein isothiocyanate (ann-V) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), and necrotic cell death was assessed by propidium iodide (PI) staining. The percentage of cells that were PI-positive increased more than six times with 20 μM AM and approximately doubled with 3.5 μM DEA, relative to control. The percentage of cells that were ann-V-positive decreased by more than 80% after 24-h exposure to 10 μM AM but more than doubled after 24-h incubation with 3.5 μM DEA. Incubation for 24 h with 5.0 μM DEA increased the percentage of cells that were TUNEL-positive more than six times. Incubation with AM (2.5 μM) or DEA (1–2 μM) for 24 h did not significantly alter angiotensinogen mRNA levels. Furthermore, angiotensin II (100 pM–1 μM) alone or in combination with AM or DEA did not alter cytotoxicity, and pretreatment with the angiotensin-converting enzyme inhibitor and antioxidant captopril (3–6 μM) did not protect against AM or DEA cytotoxicity. In conclusion, AM activates primarily necrotic pathways, whereas DEA activates both necrotic and apoptotic pathways, and the renin-angiotensin system does not seem to be involved in AM or DEA cytotoxicity in HPL1A cells.
Footnotes
This work was supported by the Canadian Institutes of Health Research [Grant MOP-13257].
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.110.173120.
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ABBREVIATIONS:
- AM
- amiodarone
- AIPT
- AM-induced pulmonary toxicity
- DEA
- desethylamiodarone
- RAS
- renin-angiotensin system
- Ang II
- angiotensin II
- ann-V
- annexin-V-fluorescein isothiocyanate
- AGTR
- angiotensin receptor
- PI
- propidium iodide
- HPL1A
- human peripheral lung epithelial cells
- PCR
- polymerase chain reaction
- TUNEL
- terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling
- PBS
- phosphate-buffered saline
- HPLC
- high-performance liquid chromatography
- ANOVA
- analysis of variance.
- Received July 19, 2010.
- Accepted November 11, 2010.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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