Dukkipati S Shekar, Chihi Aouatef, Wang Yiwen, Elbasiouny Sherif M
Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University , Dayton, Ohio 45435.
Department of Biomedical, Industrial, and Human Factors Engineering, College of Engineering and Computer Science, Wright State University , Dayton, Ohio 45435.
eNeuro. 2017 Jan 18;4(1). doi: 10.1523/ENEURO.0281-16.2016. eCollection 2017 Jan-Feb.
The possible presence of pathological changes in cholinergic synaptic inputs [cholinergic boutons (C-boutons)] is a contentious topic within the ALS field. Conflicting data reported on this issue makes it difficult to assess the roles of these synaptic inputs in ALS. Our objective was to determine whether the reported changes are truly statistically and biologically significant and why replication is problematic. This is an urgent question, as C-boutons are an important regulator of spinal motoneuron excitability, and pathological changes in motoneuron excitability are present throughout disease progression. Using male mice of the high-expresser transgenic () mouse model of ALS, we examined C-boutons on spinal motoneurons. We performed histological analysis at high statistical power, which showed no difference in C-bouton size in versus wild-type motoneurons throughout disease progression. In an attempt to examine the underlying reasons for our failure to replicate reported changes, we performed further histological analyses using several variations on experimental design and data analysis that were reported in the ALS literature. This analysis showed that factors related to experimental design, such as grouping unit, sampling strategy, and blinding status, potentially contribute to the discrepancy in published data on C-bouton size changes. Next, we systematically analyzed the impact of study design variability and potential bias on reported results from experimental and preclinical studies of ALS. Strikingly, we found that practices such as blinding and power analysis are not systematically reported in the ALS field. Protocols to standardize experimental design and minimize bias are thus critical to advancing the ALS field.
胆碱能突触输入（胆碱能终扣，即C-终扣）中病理变化的可能存在是肌萎缩侧索硬化症（ALS）领域中一个有争议的话题。关于这个问题所报告的数据相互矛盾，使得评估这些突触输入在ALS中的作用变得困难。我们的目标是确定所报告的变化在统计学和生物学上是否真的具有显著意义，以及复制存在问题的原因。这是一个紧迫的问题，因为C-终扣是脊髓运动神经元兴奋性的重要调节因子，并且在疾病进展过程中运动神经元兴奋性会出现病理变化。我们使用ALS的高表达转基因（）小鼠模型的雄性小鼠，检查了脊髓运动神经元上的C-终扣。我们以高统计效力进行了组织学分析，结果表明在整个疾病进展过程中，与野生型运动神经元相比，C-终扣大小没有差异。为了探究我们未能复制所报告变化的潜在原因，我们使用了ALS文献中报道的实验设计和数据分析的几种变体进行了进一步的组织学分析。该分析表明，与实验设计相关的因素，如分组单位、抽样策略和盲法状态，可能导致关于C-终扣大小变化的已发表数据存在差异。接下来，我们系统地分析了研究设计变异性和潜在偏倚对ALS实验研究和临床前研究报告结果的影响。令人惊讶的是，我们发现盲法和功效分析等做法在ALS领域并未得到系统报告。因此，标准化实验设计并尽量减少偏倚的方案对于推动ALS领域的发展至关重要。
