DEVELOPMENT OF NEUROPROTECTIVE STRATEGY BY THE COMBINATION THERAPY OF IMMUNOSUPPRESANT AND NEURONAL NITRIC OXIDE INHIBITOR ADMINISTRATION AGAINST NEONATAL BRAIN DAMAGE.

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15591135
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Pediatrics
• Research Institution: Tokyo Medical University
• Principal Investigator: TAKEI Yukito Tokyo Medical University, Medicine, Lecturer, 医学部, 講師 (20256259)
• Co-Investigator(Kenkyū-buntansha): TAKAMI Takeshi Tokyo Medical University, Medicine, Clinical assistant, 医学部, 助手 (20287147) ; SAITOH Tetsuya Tokyo Medical University, Medicine, Clinical assistant, 医学部, 助手 (10384968)
• Project Period (FY): 2003 – 2004
• Keywords: hypoxic-ischemic brain damage / FK506 / 7-nitroindazole / neuroprotection / dose dependency / therapeutic time window / combination therapy / neonate

Research Abstract

The goal of this study was to investigate the clinical neuroprotective strategy by means of the combination therapy of immunosuppressant, FK506, and the neuronal nitric oxide inhibitor, 7-nitroindazole, administration against hypoxic-ischemic (HI) brain damage in neonatal rats. We also investigated the dose dependency and therapeutic time window of FK506 against neonatal brain damage due to hypoxia-ischemia. The rats were performed by the transient occlusion of left carotid artery and the exposure to 8 % oxygen (HI) for 90 min. Then the brains were histologically examined 24 hrs after the HI. The HI insult induced the admixtures of the following neuronal damages; piknosis, eosinophilic change, karyorrhexis, loss of neurons, caspase 3-positive cells, spongy degeneration, and/or cystic change with macrophages in the hippocampus, frontal and temporal cortices, and/or basal ganglia. The severity of the brain damage was estimated by the extent of the damaged neurons in the brain, using the brain damage scores. The treatment of 2 mg/kg FK506 (high dose), but not 1 mg/kg (low dose), immediately after HI insult demonstrated significant decreases in the severity of the neuronal damage and caspase-3 activation 24 h after the insult, compared with vehicle injection (dose dependency). The treatment of 2 mg/kg FK506 immediately and 30 min after HI insult, but not 60 min after, demonstrated significant neuroprotective effect, compared with vehicle injection (therapeutic time window). The combination therapy of 1 mg/kg (low dose) FK506 and 7-nitroindazole demonstrated significantly more neuroprotetive effect than the single usage of either FK506 or 7NI.