Rivaroxaban improves vascular response in LPS-induced acute inflammation in experimental models

Abstract

Rivaroxaban (RVX) was suggested to possess anti-inflammatory and vascular tone modulatory effects. The goal of this study was to investigate whether RVX impacts lipopolysaccharide (LPS)-induced acute vascular inflammatory response. Male rats were treated with 5 mg/kg RVX (oral gavage) followed by 10 mg/kg LPS i.p injection. Circulating levels of IL-6, MCP-1, VCAM-1, and ICAM-1 were measured in plasma 6 and 24 hours after LPS injection, while isolated aorta was used for gene expression analysis, immunohistochemistry, and vascular tone evaluation. RVX pre-treatment significantly reduced LPS mediated increase after 6h and 24h for IL-6 (4.4±2.2 and 2.8±1.7 fold), MCP-1 (1.4±1.5 and 1.3±1.4 fold) VCAM-1 (1.8±2.0 and 1.7±2.1 fold). A similar trend was observed in the aorta for iNOS (5.5±3.3 and 3.3±1.9 folds reduction, P<0.01 and P<0.001, respectively), VCAM-1 (1.3±1.2 and 1.4±1.3 fold reduction, P<0.05), and MCP-1 (3.9±2.2 and 1.9±1.6 fold reduction, P<0.01). Moreover, RVX pre-treatment, improved LPS-induced PE contractile dysfunction in aortic rings (Control vs LPS, Emax reduction = 35.4 and 31.19%, P<0.001; Control vs LPS+RVX, Emax reduction = 10.83 and 11.48%, P>0.05, respectively), resulting in 24.5% and 19.7% change in maximal constriction in LPS and LPS+RVX respectively. These data indicate that RVX pre-treatment attenuates LPS-induced acute vascular inflammation and contractile dysfunction.

Fig 1. Role of RVX pre-treatment on LPS-induced proinflammatory and proadhesive mediator release in rat plasma.

IL-6 (A), MCP-1 (1B), VCAM-1 (C) and ICAM-1 (D) plasma levels (pg/mL) from LPS treated rats in the presence or absence of RVX for 6 hours and 24 hours compared to controls. ##P<0.01 and ###P<0.001 (Student’s t-test) vs. control conditions. *P<0.05, ** P<0.01 and ***P<0.001 (Student’s t-test) vs LPS. Values are expressed as the mean±SEM (n = 6).

Fig 2. Role of RVX pre-treatment on LPS induced proinflammatory and proadhesive mediator’s gene expression in rat aorta.

Comparisons of relative IL-6, MCP-1, VCAM-1 and ICAM-1 gene expression levels normalized to GAPDH in the rat aorta obtained from RVX- or non-treated LPS rats and non-treated control rats 6 hours (A) and 24 hours (B) post LPS exposure. *P<0.05, ** P<0.01 and ***P<0.001 indicates values significantly different (Student’s t-test) vs LPS. Values are expressed as the mean±SEM (n = 6).

Fig 3. Role of RVX pre-treatment on LPS induced proinflammatory and proadhesive mediator’s protein expression in rat aorta.

Representative immunohistochemical results for aortic iNOS (A), MCP-1 (B) and VCAM-1 (C) expressions from RVX- or non-treated LPS rats and non-treated control rats as described in the legend. % of IHC positive areas are represented as graphs. ### indicates values significantly different (Student’s t-test) vs. control conditions. *P<0.05, ** P<0.01 and ***P<0.001 indicates values significantly different (Student’s t-test) vs LPS. Values are expressed as the mean±SEM (n = 6).

Fig 4

Role of RVX on the vasoreactivity of aortic rings obtained from A) rats sacrificed 6 hours post LPS and B) rats sacrificed 24 hours post LPS to PE-induced contractions. Comparisons of vascular reactivity to PE in aortic rings from RVX- or non-treated LPS rats and non-treated control rats. *P<0.05, ** P<0.01 and ***P<0.001 indicates statistical significance (Two-Way ANOVA followed Bonferroni correction) vs. control; #P<0.05 and ##P<0.01 indicates values significantly different (Two-Way ANOVA followed Bonferroni correction) vs. LPS. Values are expressed as the ± SEM (n = 6).

Fig 5. Schematic diagram for the protection of RVX against acute inflammation and vascular dysfunction following LPS-induced endotoxin shock.

RVX pretreatment decreased the expression of pro-inflammatory mediators and adhesion molecules and improved aortic hypo responsiveness to PE induced by LPS in the aorta. The figure was prepared with BioRender (biorender.com).