THE PATHOLOGIC CHANGES OF FETAL BRAIN DURING
INTRAUTERINE ISCHEMIA AND HYPOXIA
Han YK
The Second Hospital of China
Medical University, Shenyang, China
Objective: Our purpose was to
investigate the fetal cerebral changes after intrauterine ischemia and
hypoxia, and determine whether the changes of neonatal hypoxia ischemia
encephalopathy has initiated before being delivered.
Methods: Fetal rats with gestational
age of 21 days were exposed to intrauterine ischemia by clamping the
uterine blood supplying for 0,15,30,45and 60mins respectively. Other rats
were reperfused for 1,4,8,15 and 24 hours after ischemia for 15 minutes.
All of them would be delivered by cesarean section at time points, we
determined the condition of the newborns according to some items of
neonatal Apgar score. Meanwhile, the pathologic changes of cerebral tissues
were observed by light microscope and electronic microscope, and related
these changes with the conditions of after being birth.
Results: Mild intrauterine ischemia
and hypoxia could lead to the degeneration of neurons, but the appearance
of newborn seemed normal. While in severe condition, the cerebral tissues
showed obvious necrosis, furthermore, the more severe the pathologic
changes, the more severe the conditions of newborns, even the stillbirth.
Those newborn rats ischemia for 15 minutes seemed being well, while
developed worse and worse during the 24 hours of being reperfused, which
was parallel with the developing apoptosis of cerebral neurons, and this
apoptosis process was similar with those changes that we once observed in
7-day HIE rat model.
Conclusion: Severe intrauterine
ischemia and hypoxia can make the cerebral cell necrosis before birth.
Reperfusion will lead to apoptosis. The neonatal hypoxia ischemia encephalopathy
due to perinatal asphyxia can initiate in uterus or during delivery. So the
treatment of neonatal HIE should as early as possible.