Cyclosporine A and NAC on the inducible nitric oxide synthase expression and nitric oxide synthesis in rat renal artery cultured cells

Kidney Int. 2005 Dec;68(6):2508-16. doi: 10.1111/j.1523-1755.2005.00726.x.


Background: The immunosuppressor cyclosporine A (CsA) presents the nephrotoxicity as its major side effect that is mostly attributed to a renal vasoconstriction. This may be due to an excessive generation of vasoconstrictors like reactive oxygen species (ROS), or due to a reduction of vasodilators such as the nitric oxide, which in turn, can be caused by increased amounts of ROS. We evaluated the effect of CsA and the antioxidant N-acetylcysteine (NAC) on inducible nitric oxide synthase (iNOS) mRNA expression and nitric oxide synthesis, in rat renal artery vascular smooth muscle cells (rVSMCs) primary culture.

Methods: In cells treated during 72 hours with CsA (10 microg/mL), its vehicle (control) (10 microL/mL), Escherichia coli lipopolysaccharide (LPS) (100 microg/mL), CsA + LPS, NAC (6.13 mmol/L), or CsA + NAC, we determined the nitric oxide synthesis (Griess and chemiluminescence methods), iNOS expression [reverse transcription-polymerase chain reaction (RT-PCR)] and cell viability (acridine orange method).

Results: In rVSMCs, LPS increased nitric oxide and iNOS expression; CsA decreased basal and LPS-induced nitric oxide and iNOS expression; NAC increased nitric oxide and blunted the nitric oxide reduction caused by CsA, with no effect on iNOS. CsA reduced cell viability.

Conclusion: In this study, CsA reduced nitric oxide synthesis in rVSMCs, both through iNOS down-regulation and reduction of cell viability, which could be responsible for the vasoconstrictive effect of the CsA. In the effect of CsA on nitric oxide, probably a role is also played by free radical production, as this effect was blunted by NAC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology*
  • Animals
  • Cell Survival / drug effects
  • Cells, Cultured
  • Cyclosporine / pharmacology*
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation, Enzymologic / drug effects
  • Immunosuppressive Agents / pharmacology*
  • Luminescence
  • Male
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / enzymology
  • Nitric Oxide / biosynthesis
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type II / genetics*
  • RNA, Messenger / analysis
  • Rats
  • Rats, Wistar
  • Renal Artery / cytology
  • Renal Artery / drug effects*
  • Renal Artery / enzymology


  • Immunosuppressive Agents
  • RNA, Messenger
  • Nitric Oxide
  • Cyclosporine
  • Nitric Oxide Synthase Type II
  • Nos2 protein, rat
  • Acetylcysteine