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Updated: Jan 3, 2026
3-D Imaging and Analysis of Neurons Infected In Vivo with Toxoplasma gondii
Published on: December 9, 2014
Kinematic Locomotion Changes in C57BL/6 Mice Infected with Toxoplasma Strain ME49
María de la Luz Galván-Ramírez1, Angel Gustavo Salas-Lais2, Sergio Horacio Dueñas-Jiménez1
1Laboratorio de Neurofisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Sierra Mojada 950, col.Indepdencia, Guadalajara 44320, Mexico.
Abstract:
Chronic infection with the intracellular parasite Toxoplasma gondii produces an accumulation of cysts in the brain and muscle, causing tissue damage. The cysts in the brain motor regions affect some kinematic locomotion parameters in the host. To localize the brain cysts from Toxoplasma gondii and study the changes in kinematic locomotion in C57BL/6 mice. Female adult C57BL/6 mice were infected orally with 30 ME-49 Toxoplasma gondii cysts. An uninfected group (n = 7) and two infected groups, examined 15 and 40 days postinfection, were used for this study. To evaluate kinematic locomotion, the mice were marked with indelible ink on the iliac crest, hip, knee, ankle, and phalangeal metatarsus of the left and right hindlimbs. At least three recordings were carried out to obtain videos of the left and right hindlimbs. Mice were video recorded at 90 fps at a resolution of 640 × 480 pixels while walking freely in a transparent Plexiglass tunnel. We measured the hindlimb pendular movement and the hindlimb transfer [linear displacement] curves for each step and evaluated them statistically with Fréchet dissimilarity tests. Afterward, the mice were sacrificed, and the brain, heart, skeletal muscle, lung, liver, and kidney were obtained. The different tissues were stained with hematoxylin and eosin for analysis with optical microscopy. Topographic localization of the cysts was made using bregma coordinates for the mouse brain. The cysts were distributed in several brain regions. In one mouse, cyst accumulation occurred in the hippocampus, coinciding with an alteration in foot displacement. The step length was different among the different studied groups.
Insights
Toxoplasma gondii infection causes brain cysts, altering mouse locomotion. This study mapped cyst locations and linked them to changes in hindlimb movement and step length.
Area of Science:
- Neuroparasitology
- Locomotion analysis
- Immunopathology
Background:
- Chronic infection with *Toxoplasma gondii* leads to cyst formation in host tissues, including the brain.
- Brain cysts, particularly in motor regions, can disrupt host neurological function and behavior.
- Understanding the precise localization of *Toxoplasma gondii* cysts and their impact on motor control is crucial.
Purpose of the Study:
- To identify the topographic distribution of *Toxoplasma gondii* brain cysts in C57BL/6 mice.
- To investigate alterations in kinematic locomotion parameters following *Toxoplasma gondii* infection.
- To correlate cyst location with observed changes in gait and hindlimb movement.
Main Methods:
- C57BL/6 mice were infected with *Toxoplasma gondii* and analyzed at 15 and 40 days postinfection.
- Kinematic locomotion was assessed by video recording hindlimb movements in a transparent tunnel.
- Hindlimb pendular movement and transfer curves were analyzed using Fréchet dissimilarity tests; tissues were examined histologically, and brain cysts were mapped using bregma coordinates.
Main Results:
- *Toxoplasma gondii* cysts were found distributed across multiple brain regions.
- Significant differences in step length were observed between infected and uninfected groups.
- One infected mouse showed cyst accumulation in the hippocampus, correlating with altered foot displacement patterns.
Conclusions:
- *Toxoplasma gondii* infection induces brain cyst formation that affects host locomotion.
- The study demonstrates a link between specific brain cyst localization and quantifiable changes in gait parameters.
- Further research is warranted to explore the mechanisms by which *Toxoplasma gondii* influences motor control.
