探讨在非溶血和溶血状态下，低温保藏时间对结直肠癌患者血浆miRNA标志物质量的影响。

随机抽取中山大学附属第三医院生物样本资源库2014年至2021年间在-80℃低温环境下保藏不同时间的结直肠癌血浆标本，采用分光光度计检测评估血浆溶血程度，并分为溶血组和非溶血组。miRNA提取后采用实时荧光定量PCR对潜在的结直肠癌miRNA标志物miR-92a-3p和miR-378a-5p进行丰度分析和比较。

在-80℃低温储存环境下，非溶血组保藏8年以及溶血组保藏3年的血浆中miR-92a-3p和miR-378a-5p丰度无明显变化，溶血组保藏1、3年的血浆中miR-92a-3p的丰度显著高于同期非溶血组（均P<0.01），而两组同期保藏1、3年miR-378a-5p的丰度差异无统计学意义（P=0.931、0.339）。

血浆初始溶血状态会影响循环miRNA的丰度，但低温保藏时间不影响血浆中miRNA的丰度，能较好地保持血浆样本中miRNA的稳定，用于后续研究。

To investigate the effect of preservation time on the quality of miRNA markers for colorectal cancer in non-hemolytic and hemolytic states.

Colorectal cancer plasma samples stored for different time under -80℃ from 2014 to 2021 in the Biobank of Clinical Resources of the Third Affiliated Hospital, Sun Yat-sen University were randomly selected, the degree of plasma hemolysis was assessed by spectrophotometer and divided into hemolytic group and non-hemolytic group. After miRNA extraction, the abundance of miR-92a-3p and miR-378a-5p for colorectal cancer was analyzed by quantitative real-time PCR and compared.

Under the low temperature storage environment of -80℃, there was no significant change in the abundance of miR-92a-3p and miR-378a-5p in the plasma of the non-hemolytic group preserved for 8 years and the hemolytic group preserved for 3 years. After 1 and 3 years of storage, the abundance of miR-92a-3p in plasma of hemolytic group was significantly higher than that of non-hemolytic group (both P<0.01), while there were no significant differences in the abundance of miR-378a-5p between the two groups (P=0.931, 0.339).

The initial hemolytic state of plasma may affect the abundance of circulating miRNA, but the preservation time under the low temperature does not affect the abundance of miRNA in plasma samples, thus can better maintain the stability for subsequent studies.