The Journal of infectious diseases
October 1, 2026 · via Europe PMC
An Intracisternal Rabbit Model Reveals Treponema pallidum Egress Across an Intact Blood-Brain Barrier.
Fan SH, Xie L, Zhong Y, +9 more, Lin LR.
AI summary — for doctors, generated from the abstract only
T. pallidum crossed from the central nervous system to the periphery in rabbits without breaking the blood-brain barrier.
What was studied
Intracisternal rabbit model comparing live T. pallidum, heat-inactivated organisms, and controls, tracking serology, tissue DNA, and albumin quotient over 63 days.
Key findings
- Live intracisternal infection produced serologic responses at days 7-14, similar to intravenous infection.
- T. pallidum DNA was found in brain, kidney, liver, and spleen of all live-inoculated rabbits.
- Albumin quotient stayed in the normal range, indicating intact barrier integrity.
Clinical relevance
It suggests CNS invasion by syphilis may not require barrier disruption, which affects thinking on neurosyphilis pathogenesis.
Who should care
Limitations
It is an animal model with direct CNS inoculation, which may not reflect natural human infection, and the sample sizes are not given.
No direct practice change; continue to consider CNS involvement in early syphilis as clinically indicated.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Background
Treponema pallidum (T. pallidum) can invade the central nervous system (CNS) during early infection. However, whether blood-brain barrier (BBB) disruption is required for spirochetal traversal remains unresolved.
Methods
To determine whether T. pallidum can traverse the BBB without disrupting its integrity, we established an intracisternal (i.c.) rabbit model. Systemic serological responses and T. pallidum DNA in peripheral tissues were assessed as evidence of spirochetal egress from the CNS to the periphery. BBB integrity was monitored throughout by the albumin quotient (QAlb)-a validated BBB integrity marker -with reference intervals derived from 20 healthy rabbits.
Results
The i.c. live T. pallidum group developed serological responses between day 7 and day 14, with kinetics similar to the intravenous live T. pallidum group, whereas the the i.c. heat-inactivated T. pallidum and i.c. control groups remained negative. T. pallidum DNA was detected in the brain and peripheral tissues (kidney, liver, spleen) of all i.c. live T. pallidum rabbits, but not in other groups. Throughout the 63 days, QAlb values in all i.c. groups remained within normal reference intervals, with no significant differences among groups (P > 0.05).
Conclusions
T. pallidum can disseminate from the CNS to peripheral tissues without disrupting BBB integrity. This challenges the view that BBB disruption is required for spirochetal traversal and highlights non-disruptive egress pathways.
DOI
10.1093/infdis/jiag367
PMID
42457180
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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