Yu Hua1, Kenjiro Hisano, Yuji Morimoto. 1. Department of Anesthesiology and Critical Care Medicine, Hokkaido University Graduate School of Medicine, N15 W7, Sapporo 0608638, Japan.
Abstract
PURPOSE: The effects of mild and moderate hypothermic therapy on cerebral injury are still controversial. Our hypothesis is that mild and moderate hypothermia should have some effects on neurons themselves if they really have protective effects. By using a nearly pure neuronal culture, we evaluated the effects and mechanism of hypothermia against hypoxic insult. METHODS: A nearly pure neuronal culture from cortices of 18-day-old Wister rats was used. The neurons were exposed to below 1% oxygen at 3 different temperatures (30, 33 and 37°C). First, cell viability was measured by assessing viable neurons with trypan blue. Second, to evaluate the mechanism, the extracellular glutamate concentration was measured by high-performance liquid chromatography after hypoxia; cell viability after exposure to extrinsic glutamate was also evaluated. Next, mitochondrial membrane potential was estimated, by monitoring aggregation of MitoCapture™, and the percentage of apoptotic cells was evaluated by staining with Hoechst 33342 and propidium iodide. RESULTS: After 24-h hypoxic insult, cell viability at 30 and 33°C was significantly higher than at 37°C. There was no significant difference between extracellular concentrations of glutamate after hypoxia or cell viability after glutamate exposure among the 3 temperature groups. In moderate hypothermia, the number of neurons with mitochondrial injury and the percentage of apoptotic cells were significantly reduced. CONCLUSION: Mild and moderate hypothermia inhibited hypoxic neuronal cell death. The mechanism of this effect may be related to protection of mitochondrial function, presumably followed by inhibition of apoptosis, at least in moderate hypothermia.
PURPOSE: The effects of mild and moderate hypothermic therapy on cerebral injury are still controversial. Our hypothesis is that mild and moderate hypothermia should have some effects on neurons themselves if they really have protective effects. By using a nearly pure neuronal culture, we evaluated the effects and mechanism of hypothermia against hypoxic insult. METHODS: A nearly pure neuronal culture from cortices of 18-day-old Wister rats was used. The neurons were exposed to below 1% oxygen at 3 different temperatures (30, 33 and 37°C). First, cell viability was measured by assessing viable neurons with trypan blue. Second, to evaluate the mechanism, the extracellular glutamate concentration was measured by high-performance liquid chromatography after hypoxia; cell viability after exposure to extrinsic glutamate was also evaluated. Next, mitochondrial membrane potential was estimated, by monitoring aggregation of MitoCapture™, and the percentage of apoptotic cells was evaluated by staining with Hoechst 33342 and propidium iodide. RESULTS: After 24-h hypoxic insult, cell viability at 30 and 33°C was significantly higher than at 37°C. There was no significant difference between extracellular concentrations of glutamate after hypoxia or cell viability after glutamate exposure among the 3 temperature groups. In moderate hypothermia, the number of neurons with mitochondrial injury and the percentage of apoptotic cells were significantly reduced. CONCLUSION: Mild and moderate hypothermia inhibited hypoxic neuronal cell death. The mechanism of this effect may be related to protection of mitochondrial function, presumably followed by inhibition of apoptosis, at least in moderate hypothermia.
Authors: G L Clifton; E R Miller; S C Choi; H S Levin; S McCauley; K R Smith; J P Muizelaar; F C Wagner; D W Marion; T G Luerssen; R M Chesnut; M Schwartz Journal: N Engl J Med Date: 2001-02-22 Impact factor: 91.245
Authors: Seetha Shankaran; Abbot R Laptook; Richard A Ehrenkranz; Jon E Tyson; Scott A McDonald; Edward F Donovan; Avroy A Fanaroff; W Kenneth Poole; Linda L Wright; Rosemary D Higgins; Neil N Finer; Waldemar A Carlo; Shahnaz Duara; William Oh; C Michael Cotten; David K Stevenson; Barbara J Stoll; James A Lemons; Ronnie Guillet; Alan H Jobe Journal: N Engl J Med Date: 2005-10-13 Impact factor: 91.245
Authors: Marc Schoeler; Philip D Loetscher; Rolf Rossaint; Astrid V Fahlenkamp; Georg Eberhardt; Steffen Rex; Joachim Weis; Mark Coburn Journal: BMC Neurol Date: 2012-04-11 Impact factor: 2.474
Authors: Ana Antonic; Mirella Dottori; Jessie Leung; Kate Sidon; Peter E Batchelor; William Wilson; Malcolm R Macleod; David W Howells Journal: Int J Stroke Date: 2014-01-03 Impact factor: 5.266