Inhibitory effects of 405 nm irradiation on Chlamydia trachomatis growth and characterization of the ensuing inflammatory response in HeLa cells

BMC Microbiology

Research Article

Mike T Ganger¹  Troy A Skwor²  Cassandra J Wasson³  Jessica L Zourelias⁴  Janis T Eells⁵  Justine M Schober⁶  Nathan A Aardsma⁷ 

[1]Biology Department, Gannon University, 16541, Erie, PA, USA

[2]Biology Department, Gannon University, 16541, Erie, PA, USA

[3]Department of Chemical and Biological Sciences, Rockford College, 5050 E. State St, 61108, Rockford, IL, USA

[4]Biology Department, Gannon University, 16541, Erie, PA, USA

[5]Midwestern University, Downers Grove, 60515, IL, USA

[6]Biology Department, Gannon University, 16541, Erie, PA, USA

[7]University of Buffalo, 14260, Buffalo, NY, USA

[8]Department of Biomedical Sciences, University of Wisconsin-Milwaukee, 53201, Milwaukee, WI, USA

[9]Department of Urology, University of Pittsburgh Medical Center Hamot, 16507, Erie, PA, USA

[10]Lake Erie College of Osteopathic Medicine, 16509, Erie, PA, USA

[11]Department of Pathology, University of Illinois at Chicago, 60612, Chicago, IL, USA

关键词: 405 nm;    Chlamydia trachomatis;    IL-6;    CCL2;    Phototherapy;   

DOI  :  10.1186/1471-2180-12-176

 received in 2012-05-04, accepted in 2012-08-13,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundChlamydia trachomatis is an intracellular bacterium that resides in the conjunctival and reproductive tract mucosae and is responsible for an array of acute and chronic diseases. A percentage of these infections persist even after use of antibiotics, suggesting the need for alternative treatments. Previous studies have demonstrated anti-bacterial effects using different wavelengths of visible light at varying energy densities, though only against extracellular bacteria. We investigated the effects of visible light (405 and 670 nm) irradiation via light emitting diode (LEDs) on chlamydial growth in endocervical epithelial cells, HeLa, during active and penicillin-induced persistent infections. Furthermore, we analyzed the effect of this photo treatment on the ensuing secretion of IL-6 and CCL2, two pro-inflammatory cytokines that have previously been identified as immunopathologic components associated with trichiasis in vivo.ResultsC. trachomatis-infected HeLa cells were treated with 405 or 670 nm irradiation at varying energy densities (0 – 20 J/cm2). Bacterial growth was assessed by quantitative real-time PCR analyzing the 16S: GAPDH ratio, while cell-free supernatants were examined for IL-6 and monocyte chemoattractant protein-1 (CCL2) production. Our results demonstrated a significant dose-dependent inhibitory effect on chlamydial growth during both active and persistent infections following 405 nm irradiation. Diminished bacterial load corresponded to lower IL-6 concentrations, but was not related to CCL2 levels. In vitro modeling of a persistent C. trachomatis infection induced by penicillin demonstrated significantly elevated IL-6 levels compared to C. trachomatis infection alone, though 405 nm irradiation had a minimal effect on this production.ConclusionTogether these results identify novel inhibitory effects of 405 nm violet light on the bacterial growth of intracellular bacterium C. trachomatis in vitro, which also coincides with diminished levels of the pro-inflammatory cytokine IL-6.

【 授权许可】

Unknown   
© Wasson et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.