Neonatal Chlamydia muridarum respiratory infection causes neuroinflammation within the brainstem during the early postnatal period

J Neuroinflammation. 2024 Jun 15;21(1):158. doi: 10.1186/s12974-024-03150-3.


Respiratory infections are one of the most common causes of illness and morbidity in neonates worldwide. In the acute phase infections are known to cause wide-spread peripheral inflammation. However, the inflammatory consequences to the critical neural control centres for respiration have not been explored. Utilising a well characterised model of neonatal respiratory infection, we investigated acute responses within the medulla oblongata which contains key respiratory regions. Neonatal mice were intranasally inoculated within 24 h of birth, with either Chlamydia muridarum or sham-infected, and tissue collected on postnatal day 15, the peak of peripheral inflammation. A key finding of this study is that, while the periphery appeared to show no sex-specific effects of a neonatal respiratory infection, sex had a significant impact on the inflammatory response of the medulla oblongata. There was a distinct sex-specific response in the medulla coincident with peak of peripheral inflammation, with females demonstrating an upregulation of anti-inflammatory cytokines and males showing very few changes. Microglia also demonstrated sex-specificity with the morphology of females and males differing based upon the nuclei. Astrocytes showed limited changes during the acute response to neonatal infection. These data highlight the strong sex-specific impact of a respiratory infection can have on the medulla in the acute inflammatory phase.

Keywords: Astrocytes; Cytokines; Medulla oblongata; Microglia; Sex-specific.

MeSH terms

  • Animals
  • Animals, Newborn*
  • Brain Stem / pathology
  • Chlamydia Infections* / microbiology
  • Chlamydia Infections* / pathology
  • Chlamydia muridarum*
  • Cytokines / metabolism
  • Female
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neuroinflammatory Diseases / immunology
  • Neuroinflammatory Diseases / microbiology
  • Neuroinflammatory Diseases / pathology
  • Respiratory Tract Infections / microbiology
  • Respiratory Tract Infections / pathology
  • Sex Characteristics


  • Cytokines