Fetal hydrocephalus, intrauterine diagnosis and therapy considerations: an experimental rat model.
METHODS
Fetal hydrocephalus is induced by a single intraperitoneal injection of 8 mg/kg 6-aminonikotinamide (6-AN), a niacinamide antagonist, in Sprague-Dawley rats on day 13 of gestation. Laparotomy was carried out in some rats 3, 6, 7 and 8 days after the intraperitoneal injection. The fetuses were collected by uterotomy and fixed in a formalin solution after measuring head circumference and body length for further histological investigations. The ventricular areas and volumes of the lateral ventricles were measured using a computer morphometric technique after all fetuses were serially sectioned sagittally or coronally. Furthermore, 8 maternal rats (4 treated with 6-AN and 4 controls) were used for ultrasound investigation. The fetal ventricular system and the central canal were demonstrated and compared by transabdominal ultrasound in the 6-AN and control groups. On day 19 of gestation the cerebrospinal fluid (CSF) was drained in some fetuses for 18 h through a thin micro-catheter, which was inserted into the lateral ventricle. In some other fetuses the intracranial pressure (ICP) and the intra-amniotic pressure (IAP) were measured after Doppler sonography of the cerebral blood flow (CBF). These measurements were carried out using a transuterine approach following the laparotomy.


RESULTS
Hydrocephalus was produced due to the closure of all outlets of the fourth ventricle. Macrocephalus was clear on day 17 (4 days after 6-AN injection). The entire ventricular system was dilated, including the aqueduct and foramen of Monro, and cerebellar hypoplasia was revealed.


CONCLUSIONS
Increased ICP in 6-AN fetuses was associated with decreasing CBF. The cerebral mantel was better developed after CSF drainage. The intra-amniotic pressure was increased in all pregnant rats and was either similar to or higher than ICP.
Babapour
Babak
B
Neurosurgical Department, Medical School of Hannover, Germany. babak3069@yahoo.de
Oi
Shizuo
S
Boozari
Bita
B
Tatagiba
Marcos
M
Bleck
Jörg
J
Hussein
Sami
S
Samii
Madjid
M
D015120:6-Aminonicotinamide / Q000134:cerebrospinal fluid; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005315:Fetal Diseases / Q000139:chemically induced / Q000473:pathology* / Q000628:therapy*; D005865:Gestational Age; D006849:Hydrocephalus / Q000139:chemically induced / Q000473:pathology* / Q000628:therapy*; D007427:Intracranial Pressure / Q000187:drug effects / Q000502:physiology; D007813:Laparotomy / Q000379:methods; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D015120:6-Aminonicotinamide