Therapeutic window for cycloheximide treatment after hypoxic-ischemic brain injury in neonatal rats.
We have previously shown that cycloheximide significantly inhibited apoptosis, and reduced ensuing cerebral infarction in a newborn rat model of cerebral hypoxiaischemia. This study was performed to determine the therapeutic window for cycloheximide therapy. Seven day-old newborn rat pups were subjected to 100 min of 8% oxygen following a unilateral carotid artery ligation, and cycloheximide was given at 0, 6, 12 and 24 hr after hypoxia-ischemia (HI). Apoptosis or necrosis was identified by performing flow cytometry with a combination of fluorescinated annexin V and propidium iodide, and the extent of cerebral infarction was evaluated with triphenyl tetrazolium chloride (TTC) at 48 hr and 72 hr after HI, respectively. With cycloheximide treatment at 0 hr after HI, both apoptotic and necrotic cells by flow cytometry were significantly reduced, only necrotic cells were significantly reduced at 6 and 12 hr, and no protective effect was seen if administration was delayed until 24 hr after HI compared to the HI control group. Infarct volume, measured by TTC, was significantly reduced by 92% and 61% when cycloheximide was given at 0 or 6 hr after HI respectively; however, there was an insignificant trend in infarct reduction if cycloheximide was administered 12 hr after HI, and no protective effect was observed when administration was delayed until 24 hr after HI. In summary, cycloheximide was neuroprotective when given within 6 hr after HI in the developing newborn rat brain.
Park
Won Soon
WS
Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Sung
Dong Kyung
DK
Kang
Saem
S
Koo
Soo Hyun
SH
Kim
Yu Jin
YJ
Lee
Jang Hoon
JH
Chang
Yun Sil
YS
Lee
Munhyang
M
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D002545:Brain Ischemia; D003513:Cycloheximide / Q000627:therapeutic use*; D005434:Flow Cytometry; D006801:Humans; D002534:Hypoxia, Brain; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy*; D009336:Necrosis; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D010100:Oxygen / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley
D018696:Neuroprotective Agents; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide; D010100:Oxygen