The anti-thrombotic effect of hydrogen sulfide is partly mediated by an upregulation of nitric oxide synthases

Abstract

Introduction: Hydrogen sulfide (H2S) known as a gasotransmitter is increasingly recognized for its anti-adhesive, anti-inflammatory and vasoactive properties. Due to these properties, we analysed anti-thrombotic effects of H2S and the participation of the nitric oxide synthase (NOS)-pathway.

Materials and methods: In individual venules of the ear of hairless SKH1-hr mice, thrombus formation was induced using a phototoxic light/dye-injury model and intravital fluorescence microscopy. Animals were treated intravenously with the H2S donor Na2S or NaCl as control. In a second setting, the NOS inhibitor L-NAME was applied intraperitoneally as a bolus 12h prior to Na2S treatment and thrombus induction. Blood and ear tissue were sampled after microscopy for assessment of plasma concentrations of soluble (s)P-selectin, sE-selectin, sVCAM-1 and sICAM-1 and expression of endothelial (e)NOS and inducible (i)NOS, respectively.

Results: When mice were treated with Na2S, venular thrombus formation was significantly delayed versus that in animals of the NaCl-treated control group. While plasma levels of pro-thrombotic adhesion molecules were not affected by Na2S, immunohistochemistry of the vessel walls showed a significant up-regulation of eNOS and iNOS expression within the Na2S-treated group. The delay of thrombus formation in the Na2S-group was partly but significantly reverted by application of L-NAME.

Conclusions: The anti-thrombotic efficacy of H2S involves the NOS-pathway and may be of preventive and therapeutic value for clinical disorders with increased risk of thrombotic events.

Keywords: 3-MST; 3-mercaptopyruvate sulfurtransferase; ADP; CBS; CO; CSE; FeCl(3); GP(IIb/IIIa); GP(Ib); H(2)S; ICAM-1; Intravital fluorescence microscopy; L-NAME; NG-nitro-L-arginin-methylester; NO; NO-synthase; NOS; Na(2)S; NaCl; NaHS; Nitric oxide; SKH1-hr mouse; Thrombosis; VCAM-1; adenosine diphosphate; carbon monoxide; cystathionine-β-synthase; cystathionine-γ-lyase; eNOS; endothelial nitric oxide synthase; ferric (III) chloride; glycoprotein IIb/IIIa; glycoprotein Ib; hydrogen sulfide; iNOS; inducible nitric oxide synthase; intercellular adhesion molecule-1; nitric oxide; nitric oxide synthase; s; sodium chloride; sodium hydrogen sulfide; sodium sulfide; soluble; vascular cell adhesion molecule-1.