Arnold-Chiari in a fetal rat model of dysraphism.
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.


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.


CONCLUSIONS
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.
Weber Guimarães Barreto
Maria
M
Division of Pediatric Surgery and Experimental Laboratory of Fetal Surgery, State University of Campinas-UNICAMP, Campinas, Brasil.
Ferro
Marcelo M
MM
Guimarães Bittencourt
Daniel
D
Violin Pereira
Luis A
LA
Barini
Ricardo
R
Sbragia
Lourenço
L
D000818:Animals; D001139:Arnold-Chiari Malformation / Q000473:pathology* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D008591:Meningomyelocele / Q000473:pathology / Q000503:physiopathology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D016135:Spinal Dysraphism / Q000473:pathology* / Q000503:physiopathology