A COMPARISON OF THE PROTECTIVE EFFECT OF DEXAMETHASONE TO OTHER POTENTIAL PROPHYLACTIC AGENTS IN A NEONATAL RAT MODEL OF CEREBRAL HYPOXIA-ISCHEMIA

It has recently been reported that pretreatment with a single dose of dexamethasone (0.1 mg/kg) 24 hours before hypoxia in 7-day-old rat pup s is protective against an hypoxic-ischemic insult (unilateral carotid artery occlusion followed by 3 hours of hypoxia in 8% O2). The author s now examine whether pretreatment 6 hours before insult is equally ef fective and compare other agents potentially suitable for prophylaxis in neonatal hypoxia-ischemia, including the calcium antagonists flunar izine (30 mg/kg pretreatment), nimodipine (0.5 mg/kg pretreatment), an d the 21-aminosteroid U-74389F (10 mg/kg pre- and posttreatment). For each active agent, there was also a vehicle-treated control group. Com parison of the mean area of ipsilateral infarction on brain coronal se ctions showed that there was no statistically significant difference b etween the various control groups (mean area of infarction 66% +/- 4%) . Pretreatment with dexamethasone 6 hours prior to hypoxia offered com plete protection with no infarction. A beneficial effect was seen foll owing pretreatment with flunarizine (mean area of infarction 33.6% +/- 7.8%), although this degree of damage was still significantly differe nt from that seen with dexamethasone pretreatment. Pretreatment with n imodipine or U-74389F offered no protection (mean area of infarction 7 7.5% +/- 4% and 59% +/- 10%, respectively). Unlike findings in adult a nimals and clinical studies, the current studies show that dexamethaso ne may have a role in the treatment of neonatal hypoxia-ischemia and d eserves reappraisal.