ABC 软骨素酶增强损伤后轴突的发芽,但不能显著改善行为恢复。

Chondroitinase ABC enhances pericontusion axonal sprouting but does not confer robust improvements in behavioral recovery.

机构信息

The University of California-Los Angeles (UCLA) Brain Injury Research Center, Los Angeles, California 90095-7039, USA.

出版信息

J Neurotrauma. 2010 Nov;27(11):1971-82. doi: 10.1089/neu.2010.1470. Epub 2010 Oct 20.

Abstract

Traumatic brain injury (TBI) results in enduring functional deficits. Strategies aimed at promoting plasticity within the injured brain may aid in enhancing functional outcome. We have previously shown that spontaneous pericontusional axon sprouting occurs within 7-14 days after controlled cortical impact injury in the adult rat, but ultimately fails due to an increasingly growth-inhibitory environment. We therefore sought to determine whether acute infusion of chondroitinase ABC into the site of the cortical contusion, to further reduce pericontusional growth-inhibitory chondroitin sulfate proteoglycans (CSPGs), would enhance and prolong the sprouting response. We also wanted to determine if chondroitinase-enhanced sprouting would ameliorate the behavioral deficits in forelimb function that occur in this model. Acute chondroitinase infusion decreased intact CSPGs and significantly increased pericontusional cortical grey and white matter growth-associated protein 43 (GAP43)-positive axon sprouting at 7 days post-injury. A return of intact CSPGs at later time points likely contributed to the absence of persistently increased levels of axon sprouting by 14-21 days post-injury. There was no overall benefit on forelimb function during the time of maximal sprouting or at any subsequent times in three of four behavioral outcome measures. However, there was a chondroitinase-induced improvement in recovery from unskilled limb use deficits on the staircase forelimb reaching test toward sham-injured values at 28 days, which was not achieved by the vehicle-treated rats, indicating that there is some minor functional benefit of the increased sprouting induced by chondroitinase treatment. The current results, together with data from spinal cord injury models after chondroitinase intervention, suggest that a combinatorial approach with the addition of neurotrophins and rehabilitation would result in more robust axon sprouting and consequently improve behavioral outcome.

摘要

创伤性脑损伤 (TBI) 会导致持久的功能缺陷。旨在促进受伤大脑内可塑性的策略可能有助于增强功能结果。我们之前已经表明,在成年大鼠的皮质撞击损伤后 7-14 天内,会自发地发生创伤周围轴突发芽,但最终由于生长抑制环境的增加而失败。因此,我们试图确定在皮质挫伤部位急性输注软骨素酶 ABC 是否会进一步减少创伤周围的抑制性软骨素硫酸蛋白聚糖 (CSPGs),从而增强和延长发芽反应。我们还想确定软骨素酶增强的发芽是否会改善该模型中出现的前肢功能行为缺陷。急性软骨素酶输注可减少完整的 CSPGs,并在损伤后 7 天显著增加创伤周围皮质灰质和白质的生长相关蛋白 43 (GAP43)-阳性轴突发芽。在损伤后 14-21 天,完整的 CSPGs 恢复可能导致轴突发芽水平没有持续增加。在最大发芽期间或在四个行为结果测量中的三个中的任何后续时间,都没有对前肢功能产生整体益处。然而,在 28 天时,在阶梯式前肢伸展测试中,未熟练使用肢体缺陷的恢复方面,软骨素酶诱导的改善具有优势,达到了假损伤值,而在接受载体处理的大鼠中则没有达到,这表明软骨素酶处理诱导的发芽增加具有一些较小的功能益处。目前的结果与软骨素酶干预后的脊髓损伤模型数据相结合,表明联合使用神经营养因子和康复治疗会导致更强烈的轴突发芽,从而改善行为结果。

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