eCAM Advance Access originally published online on March 14, 2007
eCAM 2008 5(1):61-69; doi:10.1093/ecam/nel110
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Oral Bromelain Attenuates Inflammation in an Ovalbumin-induced Murine Model of Asthma
1Department of Immunology and 2Department of Pediatrics, University of Connecticut School of Medicine, Farmington, CT, USA
Bromelain, a widely used pineapple extract with cysteine protease activity, has been shown to have immunomodulatory effects in a variety of immune system models. The purpose of the present study was to determine the effects of orally administered bromelain in an ovalbumin (OVA)-induced murine model of acute allergic airway disease (AAD). To establish AAD, female C57BL/6J mice were sensitized with intraperitoneal (i.p.) OVA/alum and then challenged with OVA aerosols for 3 days. Mice were gavaged with either (phosphate buffered saline)PBS or 200 mg/kg bromelain in PBS, twice daily for four consecutive days, beginning 1 day prior to OVA aerosol challenge. Airway reactivity and methacholine sensitivity, bronchoalveolar lavage (BAL) cellular differential, Th2 cytokines IL-5 and IL-13, and lung histology were compared between treatment groups. Oral bromelain-treatment of AAD mice demonstrated therapeutic efficacy as evidenced by decreased methacholine sensitivity (P
0.01), reduction in BAL eosinophils (P
0.02) and IL-13 concentrations (P
0.04) as compared with PBS controls. In addition, oral bromelain significantly reduced BAL CD19+ B cells (P
0.0001) and CD8+ T cells (P
0.0001) in AAD mice when compared with controls. These results suggest that oral treatment with bromelain had a beneficial therapeutic effect in this murine model of asthma and bromelain may also be effective in human conditions.
Keywords: airway inflammation – asthma – CD19+ B Cells – CD8+ T Cells – cysteine protease – eosinophils – IL-13 – immuno-modulation
For reprints and all correspondence: Eric R. Secor Jr, University of Connecticut Health Center, 263 Farmington Ave, MC1319, Farmington, CT 06030, USA. Tel: 860.679.8439; Fax: 860.679.1047; E-mail: esecor{at}uchc.edu
Received July 27, 2006; accepted December 4, 2006