The inflammatory response and neuronal injury in Streptococcus suis meningitis
Jana Seele1,2, Simone C Tauber3, Stephanie Bunkowski4
1Department of Neuropathology, University Medical Center Göttingen, Georg-August-University Göttingen, Göttingen, Germany. jana_seele@gmx.de.
Background:
Many of the currently used models of bacterial meningitis have limitations due to direct inoculation of pathogens into the cerebrospinal fluid or brain and a relatively insensitive assessment of long-term sequelae. The present study evaluates the utility of a Streptococcus (S.) suis intranasal infection model for the investigation of experimental therapies in meningitis.
Methods:
We examined the brains of 10 piglets with S. suis meningitis as well as 14 control piglets by histology, immunohistochemistry and in-situ tailing for morphological alterations in the hippocampal dentate gyrus and microglial activation in the neocortex.
Results:
In piglets with meningitis, the density of apoptotic neurons was significantly higher than in control piglets. Moreover, scoring of microglial morphology revealed a significant activation of these cells during meningitis. The slight increase in the density of dividing cells, young neurons and microglia observed in piglets suffering from meningitis was not statistically significant, probably because of the short time frame between onset of clinical signs and organ sampling.
Conclusions:
The morphological changes found during S. suis meningitis are in accordance with abnormalities in other animal models and human autopsy cases. Therefore, the pig should be considered as a model for evaluating effects of experimental therapeutic approaches on neurological function in bacterial meningitis.
Insights
This study shows that intranasal infection of piglets with Streptococcus suis causes bacterial meningitis, leading to increased neuron apoptosis and microglial activation. Pigs are a suitable model for testing meningitis therapies.
Area of Science:
- Neuroscience
- Infectious Diseases
- Veterinary Medicine
Background:
- Current bacterial meningitis models have limitations in pathogen delivery and sequelae assessment.
- Intranasal Streptococcus (S.) suis infection offers a potential alternative model for meningitis research.
Purpose of the Study:
- To evaluate the utility of an intranasal S. suis infection model in piglets for studying experimental meningitis therapies.
- To investigate neuropathological changes in a piglet model of bacterial meningitis.
Main Methods:
- Histology, immunohistochemistry, and in-situ tailing were used to examine piglet brains.
- Morphological alterations in the hippocampal dentate gyrus and microglial activation in the neocortex were assessed.
- 10 piglets with S. suis meningitis and 14 control piglets were studied.
Main Results:
- Piglets with meningitis exhibited significantly higher densities of apoptotic neurons compared to controls.
- Microglial morphology scoring indicated significant activation of these cells during meningitis.
- A non-significant increase in dividing cells, young neurons, and microglia was observed due to the short study timeframe.
Conclusions:
- Neuropathological findings in S. suis meningitis piglets align with observations in other models and human cases.
- The pig is a viable model for evaluating therapeutic strategies for neurological complications in bacterial meningitis.
- The intranasal infection route provides a practical method for inducing meningitis in this model.
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