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Arnold-Chiari in a fetal rat model of dysraphism
Maria Weber Guimarães Barreto1, Marcelo M Ferro, Daniel Guimarães Bittencourt
1Division of Pediatric Surgery and Experimental Laboratory of Fetal Surgery, State University of Campinas-UNICAMP, Campinas, Brasil.
Unlabelled:
Dysraphism is a defect in neural tube development, leading to dysplastic growth of the spinal cord and meninges. Myelomeningocele (MM) is just one of its forms. Hydrocephalus is among the most important alterations in MM and occurs as a consequence of Arnold-Chiari malformation (AC). Experimental models have been developed in sheep, rabbits and rats to study MM physiopathology, allowing a more detailed evaluation of clinical parameters involved in this anomaly.
Objective:
Using the experimental model of dysraphism in fetal rats, the aim of this study was to evaluate the relevance of AC malformations, clinical parameters and grade of histological lesions.
Materials And Methods:
Three groups with 16 fetuses in each were compared, MM, Control and Sham, after intrauterine surgical creation of MM on day 18.5 of gestation (term = 22 days). AC was evaluated by photographic comparison of sagittal cuts of fetal heads. Clinical and histological evaluations were also made.
Results:
88% of AC (14/16) in MM fetuses were obtained, besides 100% of clinical alterations. Necrosis and erosion of the spinal cord exposed to amniotic fluid were verified in histology.
Conclusion:
The presence of AC in the dysraphism rat model was high. These results allowed the use of this model to study alterations and intrauterine evolution of MM in a fashion similar to those observed in humans.
Insights
This study utilized a rat model to investigate neural tube defects, specifically myelomeningocele (MM) and Arnold-Chiari malformation (AC). The model successfully replicated human conditions, showing high rates of AC and clinical alterations in affected fetuses.
Area of Science:
- Developmental biology
- Neuroscience
- Teratology
Background:
- Dysraphism, including myelomeningocele (MM), involves neural tube development defects.
- Arnold-Chiari malformation (AC) is a significant complication of MM, often leading to hydrocephalus.
- Experimental models in animals are crucial for studying MM pathophysiology.
Purpose of the Study:
- To assess the utility of an experimental rat model for studying dysraphism.
- To evaluate the occurrence of Arnold-Chiari malformation (AC) in this model.
- To correlate clinical and histological findings with AC severity.
Main Methods:
- An intrauterine surgical procedure was used to create MM in fetal rats at 18.5 days of gestation.
- Three groups were studied: MM, Control, and Sham (n=16 fetuses/group).
- Arnold-Chiari malformation (AC) was assessed via photographic comparison of sagittal head sections; clinical and histological evaluations were also performed.
Main Results:
- The MM model demonstrated a high incidence of AC (88%) and 100% clinical alterations.
- Histological examination revealed spinal cord necrosis and erosion due to exposure to amniotic fluid.
- The model effectively reproduced key features of human MM and AC.
Conclusions:
- The rat model provides a high yield of Arnold-Chiari malformation (AC) in the context of dysraphism.
- This model is suitable for investigating the intrauterine development and alterations associated with myelomeningocele (MM).
- Findings in this model closely resemble human observations of MM and associated malformations.
