Prins M L, Hovda D A
Division of Neurosurgery, UCLA School of Medicine, Molecular and Medical Pharmacology, Los Angeles, California, USA.
J Neurotrauma. 1998 Oct;15(10):799-811. doi: 10.1089/neu.1998.15.799.
Previous work has demonstrated that postnatal and adult rats show different physiological responses to lateral fluid percussion (FP) brain injury. Compared to adult animals, the younger rats showed longer apnea and shorter unconsciousness, and sustained hypotension at all injury severities, with higher mortality following severe traumatic brain injury (TBI). To determine if these younger rats exhibit differential cognitive impairments, the Morris water maze (MWM) was used to compare the degree of spatial learning deficits between moderately injured postnatal day 17 (P17), P28, and adult rats, as well as their age-matched controls. Comparisons between shams of different ages showed a maturational time course for MWM acquisition, where adult rats learned the task 34-58% faster than younger age groups. Injured adults showed escape latency deficits throughout the entire training period, took 39% fewer direct paths to the platform during training, took 24% longer to reach criterion performance, and showed poor probe trial performance than adult shams. Injured P28s exhibited escape latency deficits during the first week, with 23% more trials to criterion and 24% fewer direct paths compared to P28 shams. In contrast, injured P17 rats showed no significant difference from age-matched controls in terms of escape latency, number of direct paths taken, or time to criterion performance. This work suggests that, upon surviving the insult, P17 injured rats show remarkable sparing compared to P28 and adult injured animals.
先前的研究表明，新生和成年大鼠对侧方液体冲击（FP）脑损伤表现出不同的生理反应。与成年动物相比，幼龄大鼠在所有损伤严重程度下均表现出呼吸暂停时间更长、昏迷时间更短以及持续性低血压，重度创伤性脑损伤（TBI）后的死亡率更高。为了确定这些幼龄大鼠是否表现出不同的认知障碍，采用莫里斯水迷宫（MWM）比较中度损伤的出生后第17天（P17）、P28幼龄大鼠和成年大鼠以及与其年龄匹配的对照组之间的空间学习缺陷程度。不同年龄假手术组之间的比较显示了MWM学习的成熟时间进程，成年大鼠学习任务的速度比幼龄组快34 - 58%。受伤的成年大鼠在整个训练期间均表现出逃避潜伏期缺陷，训练期间到达平台的直接路径比成年假手术组少39%，达到标准表现所需时间长24%，并且在探测试验中的表现比成年假手术组差。受伤的P28大鼠在第一周表现出逃避潜伏期缺陷，与P28假手术组相比，达到标准所需的试验次数多23%，直接路径少24%。相比之下，受伤的P17大鼠在逃避潜伏期、直接路径数量或达到标准表现所需时间方面与年龄匹配的对照组没有显著差异。这项研究表明，在经受损伤后存活下来的情况下，与P28和成年受伤动物相比，P17受伤大鼠表现出显著的恢复能力。
