Neuroprotective effect of human placental extract on hypoxic-ischemic brain injury in neonatal rats

We investigated the neuroprotective effects of human placental extracts (HPE) and the effects of HPE on recovery of cognitive and behavioral function on hypoxic-ischemic brain injury in the newborn rat. The right common carotid arteries of 7-day-old rats were coagulated, and rats were then exposed to 8% oxygen. Immediately before and again at three times after the hypoxia-ischemia (pre-treatment group), and immediately after and three times again after hypoxia-ischemia (post-treatment group), the rats were intraperitoneally injected with HPE (0.1, 0.25, or 0.5 mL/10 g/dose). No-treatment rats received saline only. On postnatal day 12, brains were removed and gross morphological damage was evaluated. To quantify the severity of brain injury, bilateral cross-sectional areas of the anterior commissural and posterior hippocampal levels were analyzed with NIH Image. Assessments of the open field activity levels at 2, 4, 6 and 8 week and, the Morris water maze test at 8 weeks after hypoxia-ischemia were carried out according to standard methods. HPE pre-treatment decreased the incidence of liquefactive cerebral infarction, at an optimally neuroprotective dose of 0.5 mL/10 g/dose (P<0.05). In the Morris water maze test, the group injected with HPE at 0.5 mL/10 g/dose concentration showed shorter escape latencies than the no-treatment group (P<0.05). These findings support a protective effect of the HPE treatment on neuronal integrity and cognitive function following hypoxic-ischemic brain injury. Injected at an appropriate dose prior to exposure, HPE may significantly reduce or prevent hypoxic-ischemic injury in the immature brain.