Temporal-spatial expressions of interleukin-4, interleukin-10, and interleukin-13 in the brains of C57BL/6 and BALB/c mice infected with Angiostrongylus cantonensis: An immunohistochemical study.

BACKGROUND: Angiostrongylus cantonensis is an important etiologic agent of eosinophilic meningitis and/or eosinophilic meningoencephalitis in humans. Th2 responses have been considered to be predominant in non-permissive hosts. However, changes of cytokines in the central nervous system of the host remain unclear. The present study was conducted to determine the temporal-spatial expressions of IL-4, IL-10, and IL-13 in the brains of infected C57BL/6 and BALB/c mice by immunohistochemistry. METHODS: After infecting each mouse with 25 third-stage larvae (L3), brain specimens were collected on day 7 and day 28 post-infection. Each specimen was cut into five sections and stained with corresponding antibodies of the three cytokines. RESULTS: In infected C57BL/6 mice, high IL-4 expressions were found in the isocortex, IL-10 in the isocortex, olfactory area, hippocampus, cerebral nuclei, hypothalamus, cerebellum nuclei, and medulla, and IL-13 in the isocortex and cerebellum. In infected BALB/c mice, IL-4 and IL-10 were highly expressed in the isocortex, olfactory areas, cerebral nuclei, hypothalamus, and cerebellum nuclei and IL-13 in the thalamus and hypothalamus. High levels of the cytokines were usually detected in on day 7 in BALB/c mice and day 28 in C57BL/6 mice. CONCLUSION: The special temporal-spatial expression changes of these three cytokines in the infected mouse brain may explain the differences in the survival and the time of occurrence of immune responses in the hosts after A. cantonensis infection.

Temporal-spatial pathological changes in the brains of permissive and non-permissive hosts experimentally infected with Angiostrongylus cantonensis.

Human cerebral angiostrongyliasis becomes an emerging disease in many parts of the world. By postmortem examination, Angiostrongylus cantonensis have been reported to cause severe pathological changes in the central nervous system. The present study was designed to determine the temporal-spatial pathological changes through experimental infections and histopathological examination of permissive (SD rats) and non-permissive (ICR mice) hosts. After infecting SD rats with 25, 50, or 100 third-stage larvae (L3) and ICR mice with 25 L3, one animal from each group was sacrificed daily from day 1 to day 30 post-infection. Each rat brain was cut into six sections and mouse brain into five sections. These sections were stained with haematoxylin and eosin and examined microscopically. Eosinophilic meningitis was found to be the most commonly pathological change and occurred on day 17 post-infection in rats with 25 L3, day 9 in the 50- or 100-L3 groups, and day 12 in infected mice. Thickness of the meninges increased 9-24 folds in infected rats and 89 folds in an infected mouse on day 28. Encephalitis, congestion, perivascular cuffing, and haemorrhage were revealed in infected mice and rats with 100 L3. Fifth-stage larvae were frequently observed in the meninges but occasionally in the parenchyma. Significant correlations between meningitis and presence of larvae in the meninges were found in the three infected rat groups but not in the infected mice. The results indicate that the clinical course of A. cantonensis infection is not self-limited but becomes more severe with the intensity of infection.