Establishment and Preliminary Analysis of an AG6 Mouse Encephalopathy Model Induced by Vaccinia Virus Tiantan Strain Infection

doi:10.12300/j.issn.1674-5817.2025.070

Abstract

Abstract:

Objective A mouse model of vaccinia virus Tiantan strain (VTT)-induced encephalopathy was developed using AG6 mice. Methods VTT was amplified by infecting Vero cells at a multiplicity of infection (MOI) of 0.01, followed by concentration and titration. After 72 h of incubation, virus-containing cells were collected and subjected to concentration. The concentrated viral suspension was serially diluted (10-fold dilutions) and added to 6-well plates containing confluent Vero cell monolayers for plaque assay. The number of plaques formed in each well was counted, and the virus titer was calculated based on the dilution factor. Fourteen 5-6-week-old AG6 mice (half male and half female, housed separately by sex) were randomly divided into a control group (n=3, PBS), a low-dose group (n=6, 1×10? PFU), and a high-dose group (n=5, 5×10? PFU). The mice were anesthetized by isoflurane inhalation and then infected via intranasal instillation. The mental state of the mice in each group was observed daily, and the body weight and mortality were recorded. On day 13 post-infection, 2% Evans Blue (4 mL/kg body weight) was administered via tail vein injection to assess blood-brain barrier (BBB) disruption. Subsequently, brain tissue samples were collected for immunofluorescence analysis to evaluate the activation of astrocytes and microglia. Results The titer of purified VTT was 1×10? PFU/mL. Compared with the control group, mice in the low-dose group showed no significant change in body weight, and no lethality was observed. In contrast, mice in the high-dose group exhibited significant weight loss starting on day 5 post-infection (P<0.05), accompanied by lethality. On day 13 post-infection, no Evans Blue extravasation was detected in the brain tissues of the low-dose group, while the olfactory bulb region of the high-dose group displayed distinct blue staining, indicating disruption of the BBB. Immunofluorescence analysis revealed no significant proliferation of astrocytes and microglia in the olfactory bulb region of the low-dose group on day 13 post-infection. In contrast, marked activation of glial cells was observable in the high-dose group. Conclusion An animal model of VTT-induced encephalopathy in AG6 mice is successfully established, characterized by BBB disruption and reactive gliosis specifically localized to the olfactory bulb region, manifested as astrocytic and microglial proliferation.

Key words: Vaccinia virus Tiantan strain, Animal model of encephalopathy, Blood-brain barrier, Glial cells, AG6 mice

CLC Number:

Q95-33

YANG Lin,JIN Meng,WU Hanqing,et al. Establishment and Preliminary Analysis of an AG6 Mouse Encephalopathy Model Induced by Vaccinia Virus Tiantan Strain Infection[J]. Laboratory Animal and Comparative Medicine, 2026, 46(1): 3-10. DOI: 10.12300/j.issn.1674-5817.2025.070.

Figures/Tables 3

References 24

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