Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, Foresterhill, University of Aberdeen, Aberdeen, Scotland, United Kingdom.
PLoS One. 2023 Aug 2;18(8):e0289472. doi: 10.1371/journal.pone.0289472. eCollection 2023.
In recent years, insufficiently characterised controls have been a contributing factor to irreproducibility in biomedical research including neuroscience and metabolism. There is now a growing awareness of phenotypic differences between the C57BL/6 substrains which are commonly used as control animals. We here investigated baseline metabolic characteristics such as glucose regulation, fasted serum insulin levels and hepatic insulin signalling in five different C57BL/6 substrains (N, J, JOla, JRcc) of both sexes, obtained from two commercial vendors, Charles River Laboratories (Crl) and Envigo (Env). Our results indicate systematic and tissue-specific differences between substrains, affected by both vendor and sex, in all parameters investigated, and not necessarily mediated by the presence of the NntC57BL/6J mutation. Not only were there differences between 6J and 6N as expected, all three 6J substrains exhibited different profiles, even from the same breeder. Two distinct metabolic profiles were identified, one in which low insulin levels resulted in impaired glucose clearance (6JCrl; both sexes) and the other, where sustained elevations in fasted basal insulin levels led to glucose intolerance (male 6JRccEnv). Further, 6JRccEnv displayed sex differences in both glucose clearance and hepatic insulin signalling markers. In comparison, the two 6N substrains of either sex, irrespective of vendor, did not exhibit considerable differences, with 6NCrl animals presenting a good choice as a healthy baseline 'control' for many types of experiments. Overall, our data emphasise the importance of selecting and characterising control subjects regarding background, sex, and supplier to ensure proper experimental outcomes in biomedical research.
近年来，在包括神经科学和代谢在内的生物医学研究中，由于对照的特征不足，导致结果不可重现。现在人们越来越意识到，作为对照动物常用的 C57BL/6 亚系之间存在表型差异。我们在此研究了来自两个商业供应商 Charles River Laboratories (Crl) 和 Envigo (Env) 的五种不同 C57BL/6 亚系（N、J、JOla、JRcc）的基线代谢特征，如葡萄糖调节、空腹血清胰岛素水平和肝胰岛素信号。我们的结果表明，在所有研究的参数中，存在由供应商和性别引起的系统性和组织特异性差异，并且不一定由 NntC57BL/6J 突变的存在介导。不仅在预期的 6J 和 6N 之间存在差异，而且所有三个 6J 亚系甚至来自同一繁殖者，都表现出不同的特征。确定了两种不同的代谢特征，一种是低胰岛素水平导致葡萄糖清除受损（6JCrl；雌雄两性），另一种是空腹基础胰岛素水平持续升高导致葡萄糖不耐受（雄性 6JRccEnv）。此外，6JRccEnv 在葡萄糖清除和肝胰岛素信号标志物方面表现出性别差异。相比之下，无论供应商如何，两种性别 6N 亚系均未表现出明显差异，6NCrl 动物是许多类型实验的良好选择，作为健康的基础“对照”。总体而言，我们的数据强调了在生物医学研究中，根据背景、性别和供应商选择和特征化对照的重要性，以确保获得适当的实验结果。
