Zhang Yinan, Luo Yi, Lu Huijuan, Wang Niansong, Shen Yixie, Chen Ruihua, Fang Pingyan, Yu Hong, Wang Congrong, Jia Weiping
1 Center for Translational Medicine, Shanghai Key Laboratory of Diabetes, The Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital , Shanghai, China .
Biopreserv Biobank. 2015 Apr;13(2):144-6. doi: 10.1089/bio.2014.0033.
Urine samples were collected from eleven randomly selected patients with kidney disease, including diabetic nephropathy, chronic nephritis, and nephritic syndrome. Urine samples were treated with one of four protocols for freezing and thawing: freeze directly and thaw directly; freeze directly and thaw by temperature gradient; freeze by temperature gradient and thaw directly; and freeze by temperature gradient and thaw by temperature gradient. After one to six freeze/thaw cycles at -20°C or -80°C, different biomarkers showed differential stabilities. The concentrations of total protein, calcium, and potassium did not change significantly after five freeze/thaw cycles at either -20°C or -80°C. Albumin could only sustain three freeze/thaw cycles at -20°C before it started to degrade. We recommend that urine be stored at -80°C as albumin and the organic ions could sustain five and six freeze/thaw cycles, respectively, using the simple "direct freeze and direct thaw" protocol. Furthermore, in most cases, gradient freeze/thaw cycles are not necessary for urine sample storage.
从11名随机选择的肾病患者中采集尿液样本，这些患者包括糖尿病肾病、慢性肾炎和肾病综合征患者。尿液样本采用以下四种冻融方案之一进行处理：直接冷冻并直接解冻；直接冷冻并通过温度梯度解冻；通过温度梯度冷冻并直接解冻；通过温度梯度冷冻并通过温度梯度解冻。在-20°C或-80°C下进行一至六个冻融循环后，不同的生物标志物表现出不同的稳定性。在-20°C或-80°C下进行五个冻融循环后，总蛋白、钙和钾的浓度没有显著变化。白蛋白在-20°C下只能承受三个冻融循环，之后就开始降解。我们建议将尿液储存在-80°C，因为使用简单的“直接冷冻并直接解冻”方案，白蛋白和有机离子分别可以承受五个和六个冻融循环。此外，在大多数情况下，尿液样本储存不需要梯度冻融循环。
