Abstract
Nitric oxide (NO) has been demonstrated to play a protective role in cell injury. In this study, we have explored the effect of NO and two NO donors (sodium nitroprusside [SNP] and isosorbide dinitrate [ISDN]) on cellular glutathione (GSH) levels in a rat lung fibroblast cell line (RFL6 cells). SNP and ISDN significantly increased cellular GSH in RFL6 cells (5 x 10(-4) M SNP: 21.9 +/- 3.6 nmol/10(6) cells and 5 x 10(-3) M ISDN: 27.6 +/- 1.7 nmol/10(6) cells versus control: 13.2 +/- 0.4 nmol/10(6) cells; P < 0.05). The stimulatory effect of SNP and ISDN on GSH was first seen at 6 h and peaked at 12 to 24 h. A similar increase in GSH was observed in RFL6 cells exposed to 400 ppm NO for 7.5 h (NO: 20.5 +/- 3.4 nmol/10(6) cells versus control: 11.9 +/- 2.4; P < 0.05). SNP and ISDN also increased cellular GSH in bovine pulmonary artery smooth muscle cells (BPSMC) and bovine pulmonary artery endothelial cells (BPAEC). Buthionine sulfoximine (BSO) (0.01 mM), an inhibitor of the GSH synthetic enzyme gamma-glutamyl cysteine synthetase, blocked the increase in GSH in RFL6 cells seen with both SNP and ISDN. In BPAEC, exposure to NO donors for 24 h stimulated glutamate uptake (SNP: 441 +/- 19 pmol/10 min/10(6) cells and ISDN: 677 +/- 48 pmol/10 min/10(6) min/10(6) cells versus control: 222 +/- 9 pmol/10 min/10(6); P < 0.05). This effect paralleled the increase in GSH. In RFL6 cells, only SNP increased glutamate uptake after 24 h of incubation. In summary, NO and NO donors increase cellular GSH in RFL6 cells, BPAEC, and BPSMC. The mechanism of this effect is unclear but may involve upregulation of the normal GSH synthetic pathways. This observation may explain in part the protective effect of NO seen in some cell culture systems and may contribute to a protective effect against oxidant injury in vivo.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: American Journal of Respiratory Cell and Molecular Biology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.