Ereifej Evon S, Rial Griffin M, Hermann John K, Smith Cara S, Meade Seth M, Rayyan Jacob M, Chen Keying, Feng He, Capadona Jeffrey R
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.
Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States.
Front Bioeng Biotechnol. 2018 Feb 12;6:9. doi: 10.3389/fbioe.2018.00009. eCollection 2018.
Clinical implantation of intracortical microelectrodes has been hindered, at least in part, by the perpetual inflammatory response occurring after device implantation. The neuroinflammatory response observed after device implantation has been correlated to oxidative stress that occurs due to neurological injury and disease. However, there has yet to be a definitive link of oxidative stress to intracortical microelectrode implantation. Thus, the objective of this study is to give direct evidence of oxidative stress following intracortical microelectrode implantation. This study also aims to identify potential molecular targets to attenuate oxidative stress observed postimplantation. Here, we implanted adult rats with silicon non-functional microelectrode probes for 4 weeks and compared the oxidative stress response to no surgery controls through postmortem gene expression analysis and qualitative histological observation of oxidative stress markers. Gene expression analysis results at 4 weeks postimplantation indicated that EH domain-containing 2, prion protein gene (Prnp), and Stearoyl-Coenzyme A desaturase 1 (Scd1) were all significantly higher for animals implanted with intracortical microelectrode probes compared to no surgery control animals. To the contrary, NADPH oxidase activator 1 (Noxa1) relative gene expression was significantly lower for implanted animals compared to no surgery control animals. Histological observation of oxidative stress showed an increased expression of oxidized proteins, lipids, and nucleic acids concentrated around the implant site. Collectively, our results reveal there is a presence of oxidative stress following intracortical microelectrode implantation compared to no surgery controls. Further investigation targeting these specific oxidative stress linked genes could be beneficial to understanding potential mechanisms and downstream therapeutics that can be utilized to reduce oxidative stress-mediated damage following microelectrode implantation.
皮质内微电极的临床植入至少在一定程度上受到了装置植入后持续发生的炎症反应的阻碍。装置植入后观察到的神经炎症反应与因神经损伤和疾病而产生的氧化应激相关。然而,氧化应激与皮质内微电极植入之间尚未有明确的联系。因此,本研究的目的是提供皮质内微电极植入后氧化应激的直接证据。本研究还旨在确定潜在的分子靶点,以减轻植入后观察到的氧化应激。在此,我们将成年大鼠植入硅非功能性微电极探针4周,并通过死后基因表达分析和氧化应激标志物的定性组织学观察,将氧化应激反应与未进行手术的对照组进行比较。植入后4周的基因表达分析结果表明,与未进行手术的对照动物相比,植入皮质内微电极探针的动物中含EH结构域2、朊病毒蛋白基因(Prnp)和硬脂酰辅酶A去饱和酶1(Scd1)均显著升高。相反,与未进行手术的对照动物相比,植入动物的NADPH氧化酶激活剂1(Noxa1)相对基因表达显著降低。氧化应激的组织学观察显示,植入部位周围氧化蛋白、脂质和核酸的表达增加。总体而言,我们的结果表明,与未进行手术的对照组相比,皮质内微电极植入后存在氧化应激。针对这些与氧化应激相关的特定基因进行进一步研究,可能有助于理解潜在机制和下游治疗方法,可用于减少微电极植入后氧化应激介导的损伤。