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Dose Dependent Nitric Oxide Production by Poloxamer 188 in Rat Isolated Hearts
Author(s) -
Douglas Hunter F,
Salzman Michele M,
Hackel Benjamin J,
Bartos Jason A,
Yannopolous Demetris,
Riess Matthias L
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1006.3
Subject(s) - poloxamer , nitric oxide , chemistry , nitric oxide synthase , ex vivo , in vivo , pulmonary surfactant , perfusion , in vitro , chromatography , medicine , biochemistry , biology , microbiology and biotechnology , polymer , organic chemistry , copolymer
Background Poloxamer 188 (P188) is a tri‐block copolymer surfactant that has demonstrated post‐ischemic cardioprotective effects ex‐ and in‐vivo. The exact mechanism is unknown; however, preliminary results suggest the protective effects may be mediated by nitric oxide (NO) production. We hypothesized that P188 will result in NO production, and this is abolished by NO synthase (NOS) inhibition. Methods Langendorff‐prepared hearts from 8 week old Brown Norway rats were perfused with Krebs solution at 37°C, saturated with 95% oxygen (O 2 ), 5% carbon dioxide (CO 2 ) at a constant perfusion pressure of 70mmHg and allowed to stabilize. Hearts were then loaded with 10μM of the NO‐sensitive fluorescent dye DAF‐FM diacetate (4‐amino‐5‐methylamino‐2′,7′‐difluorofluorescein diacetate). P188 was administered in increasing concentrations (0mM, 0.1mM, 0.3mM, 1.0mM, and 3.0mM) ± 100μM of the nonspecific NOS inhibitor L‐NAME (Nω‐Nitro‐L‐arginine methyl ester). After 10min of exposure to each concentration of P188, DAF‐fluorescence was measured using a bifurcated fiber optic probe in contact with the left ventricular epicardial wall (495/515nm excitation/emission). Values are ± SEM. Statistics: ANOVA followed by Student Newman Keul; p<0.05 *vs control. Results P188 led to a concentration‐dependent increase in DAF‐fluorescence of *3.6%±0.7 vs 1.0%±0.4, 7.3%±3.3 vs 4.9%±1.4, 10.1%±4.0 vs 2.5%±1.3, and *26.2%±5.1 vs 1.1%±0.4%. This was completely abolished by L‐NAME. Conclusion Our results support the notion that the protective effect of P188 is, at least in part, mediated by NO release. Support or Funding Information This work was supported by the NIH (R01 HL095122) and institutional funds. None of the authors have a conflict of interest.