In utero topographic analysis of astrocytes and neuronal cells in the spinal cord of mutant mice with myelomeningocele.
OBJECTIVE
Myelomeningocele (MMC) is the most severe form of spina bifida causing severe neurological deficits. Injury to the placode has been attributed to in utero aggression. In this study, glial and neuronal cell changes in both number and topography in mice with MMC were investigated during gestation.


METHODS
The curly tail/loop-tail mice model of MMC was used, and fetuses were harvested using caesarean surgery at Days 14.5, 16.5, and 18.5 (full gestation at 19 days). Immunohistochemical analyses of the MMC placodes and the normal spinal cords from the control group were performed using anti-glial fibrillary acidic protein (astrocytes) and mouse anti-neuronal nuclear (neurons) antibodies. Light microscopy was used along with computer-assisted morphometric evaluation. Progressive increases in astrocytes in the spinal cord of all mouse fetuses were found between Days 14.5 and 18.5 of gestation. This increase was significantly higher in the placodes of mice with MMC than in those of normal mice, particularly in the posterior region. Neuronal labeling at Day 14.5 of gestation was similar between mice with MMC and control mice. At Day 16.5 of gestation there was a deterioration of neural tissue in MMC fetuses, mainly in the posterior region, progressing until the end of gestation with a marked loss of neurons in the entire MMC placode.


CONCLUSIONS
This study delineated the quantitative changes in astrocytes and neurons associated with MMC development during the late stages of gestation. The detailed topographic analysis of the MMC defines the timing of the intrauterine insult and how the placode lesions progress. This study supports the current concept of placode protection through in utero surgery for fetuses with MMC.
Reis
Joaquim L
JL
Department of Anatomy, Abel Salazar Institute for Biomedical Sciences (ICBAS) and Unit for Multidisciplinary for Biomedical Research (UMIB), University of Porto, Portugal. jlreis@icbas.up.pt
Correia-Pinto
Jorge
J
Monteiro
Mariana P
MP
Hutchins
Grover M
GM
D000818:Animals; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology*; D018450:Disease Progression; D004622:Embryo, Mammalian / Q000378:metabolism / Q000473:pathology; D047108:Embryonic Development; D005260:Female; D005865:Gestational Age; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008591:Meningomyelocele / Q000196:embryology* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008817:Mice, Mutant Strains; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D013116:Spinal Cord / Q000196:embryology* / Q000378:metabolism / Q000473:pathology; D013194:Staining and Labeling