Abstract:

Ｏｂｊｅｃｔｉｖｅ：To investigate the quality and yield of DNA extracted from blood cell after longterm(more than 10 years) storage at -80℃.
Ｍｅｔｈｏｄｏｌｏｇｙ：The 150 blood cell samples enrolled in the study were selected from the Renal Biobank of National Clinical Research Center of Kidney Diseases,which were isolated from 3 ml anticoagulant blood having been preserved for more than 10 years.Extraction of DNA was performed on automatic nucleic acid extraction instrument by magnetic beads method.Assay of the purity and yield of DNA by Nanodrop and the integrity by agarose gel electrophoresis.
Ｒｅｓｕｌｔｓ：Of the DNA extracted from 150 blood cell sampels,the mean value of A260/A280 is 184,A260/A230 is 227 and yield is 18757 μgAgarose gel electrophoresis showed that all the DNA bands were relatively concentrated without dispersion distribution,and DNA molecular weight larger than 20 kb.In the 150 DNA samples,there are 134 DNA 17≤A260/A280≤19,accounting for 893%,120 DNA A260/A230≥20,accounting for 80%,115 DNA 17≤A260/A280≤19 and A260/A230≥20,accounting for 767%.The yield of 143 DNA ≥10 μg,accounting for 953%.Of which,there are 132 DNA yield≥10 μg and 17≤A260/A280≤19,accounting for 88%.Further,114 DNA yield≥10 μg,17≤A260/A280≤19，and A260/A230≥20,accounting for 76%.
Ｃｏｎｃｌｕｓｉｏｎ：
DNA extracted from blood cell samples by magnetic beads mostly remains high quality and quantity after longterm cryopreservation in our center,which can meet the demand of downstream experiments.This research offers a reference for selecting samples for scientific research that had been preserved for more than 10 years in Biobank.

Key words: blood cell samples, long-termcryopreservation, DNA