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Heart 99:570-576 doi:10.1136/heartjnl-2012-303355
  • Basic research
  • Original article

Interleukin 6 augments mechanical strain-induced C-reactive protein synthesis via the stretch-activated channel–nuclear factor κ B signal pathway

  1. Lilong Tang1
  1. 1Division of Cardiology, Union Hospital, Fujian Medical University Fuzhou, Fuzhou, Fujian, China
  2. 2Division of Cardiology and Cardiac Surgery, the First affiliated Hospital to SU, Guangzhou, Guangdong, China
  3. 3Division of Geriatrics, The Affiliated People Hospital to Jiangsu University, HuaiAn, China
  4. 4Division of Cardiology, Xiangtan Central Hospital, Xiangtan, Hunan, China
  5. 5Division of Cardiology, Rimin Hospital of Hunan Province, Changsha, Hunan, China
  1. Correspondence to Dr Lilong Tang, Department of Cardiology, Union Hospital, Fujian Medical University, Fujian Institute of Coronary Artery Disease, Fuzhou, Fujian 350001, China; lilong_tang{at}yahoo.com
  • Received 12 November 2012
  • Revised 12 November 2012
  • Accepted 20 November 2012
  • Published Online First 20 December 2012

Abstract

Objectives C-reactive protein (CRP), an inflammation marker, is a strong independent risk factor for cardiovascular disease. Vessels are able to express CRP; however, the molecular mechanism behind this expression is not clear.

Methods Reverse transcription PCR and ELISA were used to detect messenger RNA and proteins of CRP and nuclear factor κB (NF-κB) activity in vessel rings stretched with different mechanical strains.

Results Interleukin (IL)-6 treatment did not induce CRP expression in vessel rings of white rabbits in the absence of mechanical strain. In contrast, IL-6 augmented CRP expression in vessel rings stretched with mechanical strains of 3 and 5 g (CRP mRNA, IL-6: 11.367±1.68 and 12.78±0.76 vs vehicle: 7.27±0.88 and 8.3±0.91 folds, respectively; CRP, IL-6: 12.79±1.62 and 14.05±2.1 vs vehicle: 7.72±1.04 and 8.16±1.52 folds, respectively; p<0.05 vs 0 g group and vehicle control group; n=5), and this effect was completely blocked by treatment with gadolinium III chloride hexahydrate (GdCl3). Moreover, IL-6 treatment increased NF-κB activity in vessels stretched with a mechanical strain of 3 g, and this effect was blocked by stretch-activated channel inhibitors (streptomycin or GdCl3) and the NF-κB peptide inhibitor SN50, but not by the inactive SN50 analogue SN50M. We also performed similar experiments on human internal mammary arteries and obtained similar results.

Conclusions These results indicate that the inflammatory cytokine IL-6 alone does not induce CRP synthesis in vessels in the absence of mechanical strain; however, IL-6 augments mechanical strain-induced CRP synthesis in vessels via the stretch-activated channel–NF-κB pathway.