Ambroxol Treatment Suppresses the Proliferation of Chlamydia pneumoniae in Murine Lungs

Abstract

Ambroxol (Ax) is used as a mucolytics in the treatment of respiratory tract infections. Ax, at a general dose for humans, does not alter Chlamydia pneumoniae growth in mice. Therefore, we aimed to investigate the potential anti-chlamydial effect of Ax at a concentration four timed higher than that used in human medicine. Mice were infected with C. pneumoniae and 5-mg/kg Ax was administered orally. The number of recoverable C. pneumoniae inclusion-forming units (IFUs) in Ax-treated mice was significantly lower than that in untreated mice. mRNA expression levels of several cytokines, including interleukin 12 (IL-12), IL-23, IL-17F, interferon gamma (IFN-γ), and surfactant protein (SP)-A, increased in infected mice treated with Ax. The IFN-γ protein expression levels were also significantly higher in infected and Ax-treated mice. Furthermore, the in vitro results suggested that the ERK 1/2 activity was decreased, which is essential for the C. pneumoniae replication. SP-A and SP-D treatments significantly decreased the number of viable C. pneumoniae IFUs and significantly increased the attachment of C. pneumoniae to macrophage cells. Based on our results, a dose of 5 mg/kg of Ax exhibited an anti-chlamydial effect in mice, probably an immunomodulating effect, and may be used as supporting drug in respiratory infections caused by C. pneumoniae.

Anti-chlamydial effects of azelastine hydrochloride and the impact of the histamine H1 receptor on chlamydial development

“…While NAC increased CP infection, ambroxol did not impact CP growth in mice at clinically relevant concentrations [27]. The 4-fold increased ambroxol concentration (still tolerable in vivo ), however, suppressed CP proliferation in murine lungs, leading the authors to conclude that ambroxol could be used as a supportive drug to treat chlamydial respiratory infections [28]. Whether these pharmaceutical interactions with chlamydial development will ultimately be applied in the clinical setting remains to be seen.…”