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The impacts of anti-inflammatory phosphodiesterase inhibitors on a murine model of chronic pulmonary inflammation
  • Xiaofang Zheng,
  • Jin-Nong Zhang ,
  • Lu-Qian Zhou
Xiaofang Zheng
Wuhan Union Hospital
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Jin-Nong Zhang
Huazhong University of Science and Technology
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Lu-Qian Zhou
Guangzhou Medical University
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Abstract

Chronic obstructive pulmonary disease (COPD) often tends to respond poorly to glucocorticoid (GC) therapy. Reduced Histone deacetylase-2 (HDAC-2) activity is an important mechanism behind this GC insensitivity. In this study, we investigated the effects of three phosphodiesterase inhibitors (PDEIs), with anti-inflammatory propensity, on cigarette smoke (CS) induced pulmonary inflammation and HDAC-2 activity. Male C57BL/6 mice were exposed to cigarette smoke (CS) over the course of 30 weeks. Administration of the PDEIs commenced from the 29th week and followed a schedule of once daily treatments, 5 days a week, for 2 weeks. Roflumilast (ROF) was administered intragastrically (5 mg·kg-1), while pentoxifylline (PTX) (10 mg·kg-1) and theophylline (THEO) (10 mg·kg-1) were administered intraperitoneally, either alone or in combination with a GC (triamcinolone acetonide or TRI, 5 mg·kg-1, i.m., single injection). Lung morphometry, as well as the activity of HDAC-2, pro-inflammatory cytokines and reactive oxygen species (ROS) were assessed at the end of the 30 week course. CS exposure was associated with a reduction in HDAC-2 activity and the up-regulation of ROS expression. PTX, ROF and THEO administration led to the partial restoration of HDAC-2 activity, however combining TRI to any of these PDEIs did not synergistically augment this effect. The restoration of HDAC-2 activity was favorably associated with the reduction of ROS expression.Inactivation of HDAC-2 due to long-term CS exposure is closely related to exaggerated oxidative stress, and this reduced HDAC-2 activity could partially be restored through the use of PDEIs. This finding provides a potential novel approach for further clinical research.