Sun Xiaochuan, Tang Wenyuan, Zheng Luping
Department of Neurosurgery, First Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400016, China.
Chin J Traumatol. 2002 Dec;5(6):355-60.
To investigate the effect of moderate hypothermia on responses of axonal cytoskeleton to axonal injury in the acute stage of injury.
Of fifteen adult guinea pigs, twelve animals were subjected to stretch injury to the right optic nerves and divided into the normothermic group (n = 6) in which the animal's core temperature was maintained at 36.0-37.5 degrees C and the hypothermia group (n = 6) in which the core temperature was reduced to 32.0-32.5 degrees C after stretch injury. Remaining three animals sustained no injury to the right optic nerves and served as control group. Half of injured animals (n = 3) of either normothermic group or hypothermic group were killed at either 2 hours or 4 hours after injury. The ultrastructural changes of axonal cytoskeleton of the right optic nerve fibers from the animals were examined under a transmission electron microscope and analyzed by quantitative analysis with a computer image analysis system.
At 2 hours after stretch injury, there was a significant reduction in the mean number of microtubules (P < 0.001), and a significant increase in the mean intermicrotubule spacing (P < 0.05 or P < 0.01) in axons of all sizes in normothermic animals. The mean number of neurofilaments also decreased statistically (P < 0.01) in large and medium subgroups of axons in the same experimental group at 2 hours. By 4 hours, the large subgroup of axons in normothermic animals still demonstrated a significant decline in the mean number of microtubules (P < 0.01) and an increase in the mean intermicrotubule spacing (P < 0.05), while the medium and small subgroups of axons displayed a significant increase in the mean number of neurofilaments (P < 0.05) and reduction in the mean interneurofilament spacing (P < 0.05). On the contrary, either the mean number of microtubules and the mean intermicrotubule spacing, or the mean number of neurofilaments and interneurofilament spacing in axons of all sizes in hypothermic stretch-injured animals was not significant different from the mean values of sham-operated animals.
Posttraumatic moderate hypothermia induced immediately after axonal injury results in substantial protection of axonal cytoskeleton and ameliorates axonal damage.
探讨亚低温对轴突损伤急性期轴突细胞骨架对轴突损伤反应的影响。
15只成年豚鼠中，12只动物右侧视神经遭受牵拉损伤，并分为正常体温组（n = 6），其动物核心体温维持在36.0 - 37.5摄氏度，以及亚低温组（n = 6），其在牵拉损伤后核心体温降至32.0 - 32.5摄氏度。其余3只动物右侧视神经未受损伤，作为对照组。正常体温组或亚低温组的半数损伤动物（n = 3）在损伤后2小时或4小时处死。对这些动物右侧视神经纤维轴突细胞骨架的超微结构变化在透射电子显微镜下进行检查，并使用计算机图像分析系统进行定量分析。
牵拉损伤后2小时，正常体温动物所有大小轴突中的微管平均数量显著减少（P < 0.001），微管间平均间距显著增加（P < 0.05或P < 0.01）。在同一实验组中，损伤后2小时，大中轴突亚组中的神经丝平均数量也有统计学下降（P < 0.01）。到4小时时，正常体温动物的大轴突亚组仍显示微管平均数量显著下降（P < 0.01），微管间平均间距增加（P < 0.05），而中小轴突亚组显示神经丝平均数量显著增加（P < 0.05），神经丝间平均间距减小（P < 0.05）。相反，亚低温牵拉损伤动物所有大小轴突中的微管平均数量和微管间平均间距以及神经丝平均数量和神经丝间平均间距与假手术动物的平均值相比无显著差异。
轴突损伤后立即诱导的创伤后亚低温可对轴突细胞骨架产生实质性保护并减轻轴突损伤。
