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[Histopathological changes in EV71-infected mouse model:a transmission electron microscopic study]
Pin Yu1, Linlin Bao1, Lili Xu1
1Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Comparative Medicine Center, Peking Union Medical Collage; Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Beijing 100101, China.
Objective:
To document ultrastructural changes of brain, spinal cord, skeletal muscle, jejunum and lung of EV71 infection mouse model, and to explore the myotropism and pathogenesis of EV71 in nervous system.
Methods:
Ten-day-old suckling mice were infected with EV71 strain via the intraperitoneal route. Mice with paralysis were scarified on day 4 post infection and the brain, spinal cord, skeletal muscle, jejunum and lung were sampled for transmission electron microscopy and light microscopy.
Results:
Lesions in brain were generally mild with inner chamber swelling in some of mitochondria. Myelin sheaths of medullated fibers were split with vacuolated changes. The Nissl bodies in anterior motor neurons disappeared along with mitochondria swelling, rough endoplasmic reticulum swelling and degranulation. Cytoplasm of anterior motor neurons showed cribriform appearance accompanied by neuronophagia. The bands of skeletal muscle in the infected group disappeared with degeneration and karyopyknosis in myocytes, in addition to mitochondrial swelling. Microvilli of epithelium in jejunum became loosely arranged along with formation of spiral medullary sheath structure and mitochondria swelling. Interstitial pneumonia was observed in lungs with type II pneumocyte proliferation and evacuation of the multilamellar bodies.
Conclusions:
EV71 infection causes severe myositis in the mouse model suggesting a strong myotropism of EV71 virus. The presence of lesions of various degrees in central nervous system and changes in anterior motor neurons may be associated with limb paralysis.
Insights
Enterovirus 71 (EV71) infection causes severe muscle damage and affects the central nervous system in a mouse model. These findings suggest EV71 has a strong affinity for muscle tissue and may cause paralysis through neurological damage.
Area of Science:
- Virology
- Neuropathology
- Infectious Diseases
Context:
- Enterovirus 71 (EV71) is a significant human pathogen causing hand, foot, and mouth disease, which can lead to severe neurological complications.
- Understanding the tissue tropism and pathogenesis of EV71 is crucial for developing effective treatments and preventative strategies.
Purpose:
- To document the ultrastructural changes in various organs of a mouse model infected with EV71.
- To investigate the myotropism and pathogenesis of EV71 within the nervous system.
Summary:
- Mice infected with EV71 exhibited mild brain lesions, including mitochondrial swelling and myelin sheath vacuolation.
- Anterior motor neurons showed degeneration, with disappearing Nissl bodies and neuronophagia, while skeletal muscles displayed degeneration and myocyte karyopyknosis.
- Jejunum epithelium showed disrupted microvilli, and lungs developed interstitial pneumonia with type II pneumocyte proliferation.
Impact:
- The study demonstrates severe myositis in the EV71 mouse model, indicating significant myotropism.
- Observed lesions in the central nervous system and anterior motor neurons correlate with limb paralysis, highlighting EV71's neurovirulence.
