Changes of nerve growth factor in amniotic fluid and correlation with ventriculomegaly.

OBJECTIVE: To detect the change of nerve growth factor (NGF) level in human amniotic fluid during gestation, and to explore the relationship between this change and fetal ventriculomegaly (VM). METHODS: The studied subjects (collected from 2004 to 2007) were divided into four groups, including the second-trimester pregnancy group (n=113), third-trimester pregnancy group (n=110), fetal cerebral VM group (n=12), and healthy control group (n=12) which matched with the VM group in gestational weeks. The amniotic fluid specimens were obtained during amniocentesis or cesarean section. The NGF levels in amniotic fluid were detected with enzyme-linked immunosorbent assay. RESULTS: A significantly negative correlation was found between gestational age and the NGF level in amniotic fluid (r=−0.6149, P<0.0001). The NGF level in patients with fetal VM was significantly lower than that in healthy controls (33.95±29.24 pg/mL vs. 64.73±16.21 pg/mL, P=0.024). CONCLUSION: NGF levels in amniotic fluid may be a sensitive marker for fetal VM.

Effects of graded hypothermia on hypoxic-ischemic brain damage in the neonatal rat.

OBJECTIVE: To investigate the effect of graded hypothermia on neuropathologic alterations of neonatal rat brain after exposed to hypoxic-ischemic insult at 37°C, 33°C, 31°C, and 28°C, respectively, and to observe the effect of hypothermia on 72-kDa heat shock protein (HSP72) expression after hypoxic-ischemic insult. METHODS: Seven days old Wistar rats were subjected to unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 2 hours at 37°C, 33°C, 31°C, and 28°C, respectively. The brain temperature was monitored indirectly by inserting a mini-thermocouple probe into the temporal muscle during hypoxia. After hypoxia-ischemia their mortality was assessed. Neuronal damage was assessed with HE staining 72 hours after hypoxia. HSP72 expression at 0.5, 24, and 72 hours of recovery was immunohistochemically assessed using a monoclonal antibody to HSP72. RESULTS: Hypoxia-ischemia caused 10.5% (2/19) of mortality in rat of 37°C group, but no death occurred in 33°C, 31°C or 28°C groups. HE staining showed neuropathologic damage was extensive in rats exposed to hypoxia-ischemia at 37°C (more than 80.0%). The incidence of severe brain damage was significantly decreased in 33°C (53.3%) and 31°C groups (44.4%), and no histologic injury was seen in the 28°C group of rats. Expression of HSP72 was manifest and persistent in the rat brain of 37°C group, but minimum in the rat brain of 28°C group. CONCLUSION: Mild and moderate hypothermia might prevent cerebral visible neuropathologic damage associated with hypoxic-ischemic injury by decreasing stress response.

Effect of propentofylline on hypoxic-ischaemic brain damage in newborn rat.

BACKGROUND: Studies showed that propentofylline enhances the action of adenosine and protects hippocampal neuronal damage against transient global cerebral ischaemia. Our study was to investigate the effect of propentofylline on hypoxic-ischaemic brain damage in neonatal rat. METHODS: Seven-day-old Wistar rats were subjected to unilateral common carotid artery ligation and hypoxia in oxygen 8 kPa for two hours at 37 degrees C. Propentofylline (10 mg/kg) was administered intraperitoneally one hour after hypoxia-ischaemia (treated group). Control group rats were received an equivalent volume of saline. The effects of propentofylline were assessed by observing the body mass gain, behavioural alteration and neurohistological changes. The rats were sacrificed at 72 hours after hypoxia-ischaemia, and the brain sections were examined after haematoxylin and eosin staining. RESULTS: The propentofylline-treated rats had better body mass gain and better behavioural response than the paired saline-controls did. In the control group, the rats either lost body mass or had little mass gain after the insult, their average body mass gain was 97.3% at 24 h, 100.3% at 48 h, and 114.1% at 72 h of recovery. In propentofylline-treated group, there was a significant improvement of body mass gain at 24 h (100.2%, P < 0.05) and 48 h (110.3%, P < 0.01) of recovery; the percentage of rats that performed well on behavioural test was significantly higher from 48 h to 72 h of recovery (P < 0.05); the incidence of severe brain damage to the cerebral cortex and dentate gyrus was significantly reduced in propentofylline-treated rats (cortex, 93% - 70.8%, P < 0.01; dentate gyrus 95% - 66.7%, P < 0.01) as compared with control rats. CONCLUSIONS: Administration of propentofylline 1 hour after hypoxia-ischaemia significantly attenuates brain damage in both the cerebral cortex and dentate gyrus, and also improves the body mass gain as well as behavioural disturbance in 7-day-old rats.

Usefulness of percutaneous intracardiac administration of colored microspheres in measuring blood flow distribution to the brain in 7-day-old rats.

OBJECTIVE: By using colored microsphere (CMS) technique in newborn rats, we explored the relationship between injection sites and blood flow distribution patterns in open-chest and in closed-chest models, with hopes that percutaneous left ventricle injection can be applicable to measure relative blood flow distribution to the brain. METHODS: Seven-day-old Wistar rats were used. In open-chest models (n = 30), we exposed the heart and injected CMS (15 microm diameter, 125000 spheres in 0.05 mL) to left and right ventricles, respectively. In closed-chest models (n = 12), we percutaneously punctured the left ventricle to administer microspheres to see the difference in blood flow distribution between the right and left side of organs. Microsphere counts were compared between the left and right side of each organ by unpaired t-test (mean +/- SD). RESULTS: Open-chest showed that right ventricle injection resulted in exclusive entrapment in the lungs, while left ventricle injection resulted in systemic distribution. According to this, one of 12 injections in the closed-chest was judged as right ventricle injection. The other 11 showed insignificant differences between the right and left side in the cortex, lung, and kidney. CONCLUSION: Right ventricle injection is differentiated from left ventricle injection and microsphere counts are the same between right and left side of the organs, suggesting that percutaneous microsphere injection is applicable for relative blood flow distribution in 7-day-old rat models.

Cerebral blood flow distribution and hypoxic-ischemic brain damage in newborn rats.

OBJECTIVE: Our purpose was to assess the cerebral blood flow distribution and resulting grade of hypoxicischemic brain damage in newborn rats. METHODS: Seven-day-old Wistar rats (n = 75) underwent left common carotid artery ligation followed by 2 hours hypoxia (8% oxygen in nitrogen) at 33 degrees C. The control animals were exposed to hypoxia without ligation (n = 8). Colored microspheres of 15 microm in diameter were administered into the left cardiac ventricle percutaneously at the end of hypoxia. They were killed 24 hours after induced injury. Brain sections 2 mm in thickness were removed for microtubule-associated protein 2 (MAP-2) staining, and remaining parts were separated into left and right hemispheres for counting the microspheres. The blood flow distribution to the ligated side was expressed as the difference from the non-ligated control side. Severity of MAP-2 disappearance was ranked as normal, mild or severe. RESULTS: In the control rats, there was no loss of MAP-2 staining. The blood flow equally distributed into both cerebral hemispheres. The cerebral blood flow distribution on the side of carotid artery ligation decreased by 44.7 +/- 21.9% in the mildly damaged group and 65.8 +/- 16.8% in the severely damaged group. CONCLUSION: The greater the percentage difference of blood flow distribution from the non-ligated side, the more severe the brain damage.