Heme oxygenase-1-Dependent anti-inflammatory effects of atorvastatin in zymosan-injected subcutaneous air pouch in mice

PLoS One. 2019 May 9;14(5):e0216405. doi: 10.1371/journal.pone.0216405. eCollection 2019.


Statins exert pleiotropic and beneficial anti-inflammatory and antioxidant effects. We have previously reported that macrophages treated with statins increased the expression of heme oxygenase-1 (HO-1), an inducible anti-inflammatory and cytoprotective stress protein, responsible for the degradation of heme. In the present study, we investigated the effects of atorvastatin on inflammation in mice and analyzed its mechanism of action in vivo. Air pouches were established in 8 week-old female C57BL/6J mice. Atorvastatin (5 mg/kg, i.p.) and/or tin protoporphyrin IX (SnPPIX), a heme oxygenase inhibitor (12 mg/kg, i.p.), were administered for 10 days. Zymosan, a cell wall component of Saccharomyces cerevisiae, was injected in the air pouch to trigger inflammation. Cell number and levels of inflammatory markers were determined in exudates collected from the pouch 24 hours post zymosan injection by flow cytometry, ELISA and quantitative PCR. Analysis of the mice treated with atorvastatin alone displayed increased expression of HO-1, arginase-1, C-type lectin domain containing 7A, and mannose receptor C-type 1 in the cells of the exudate of the air pouch. Flow cytometry analysis revealed an increase in monocyte/macrophage cells expressing HO-1 and in leukocytes expressing MRC-1 in response to atorvastatin. Mice treated with atorvastatin showed a significant reduction in cell influx in response to zymosan, and in the expression of proinflammatory cytokines and chemokines such as interleukin-1α, monocyte chemoattractant protein-1 and prostaglandin E2. Co-treatment of mice with atorvastatin and tin protoporphyrin IX (SnPPIX), an inhibitor of heme oxygenase, reversed the inhibitory effect of statin on cell influx and proinflammatory markers, suggesting a protective role of HO-1. Flow cytometry analysis of air pouch cell contents revealed prevalence of neutrophils and to a lesser extent of monocytes/macrophages with no significant effect of atorvastatin treatment on the modification of their relative proportion. These findings identify HO-1 as a target for the therapeutic actions of atorvastatin and highlight its potential role as an in vivo anti-inflammatory agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Atorvastatin / pharmacology*
  • Cell Movement / drug effects
  • Female
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Heme Oxygenase-1 / biosynthesis*
  • Inflammation / chemically induced
  • Inflammation / drug therapy
  • Inflammation / epidemiology
  • Inflammation / pathology
  • Macrophages / enzymology
  • Macrophages / pathology
  • Membrane Proteins / biosynthesis*
  • Metalloporphyrins / pharmacology
  • Mice
  • Monocytes / enzymology
  • Monocytes / pathology
  • Neutrophils / enzymology
  • Neutrophils / pathology
  • Protoporphyrins / pharmacology
  • Zymosan / toxicity*


  • Anti-Inflammatory Agents
  • Membrane Proteins
  • Metalloporphyrins
  • Protoporphyrins
  • Zymosan
  • Atorvastatin
  • tin protoporphyrin IX
  • Heme Oxygenase-1
  • Hmox1 protein, mouse

Grant support

This study has been funded with supports from the National Council for Scientific Research in Lebanon (to AH and EH, 02-05-16), the Medical Practice Plan (MPP to AH), the Faculty of Medicine of the American University of Beirut (to AH), the Ecole Doctorale Des Sciences et Technologie of the Lebanese University (to E.H.), INSERM (To RM), the Université Paris-Est Créteil (to RM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.