DETECTION OF STRAND BREAKS OF DNA IN HUMAN EARLY CHORIONIC VILLUS CELLS INDUCED BY DIAGNOSTIC ULTRASOUND USING 32p-LABELED ALU HYBRIDIZATION / 药物分析学报

ABSTRACT

Objective To explore if strand breaks of DNA in human early chorionic villus cells in uterus were induced by diagnostic ultrasound and to evaluate the method used for detection of single-stranded breaks and doublestranded breaks in human DNA. Methods 60 normal pregnant women aged 20-30, who underwent artificial abortion during 6-8 weeks of gestation, were randomly divided into 2 experimental groups All 30 cases were exposed to diagnostic ultrasound in uterus for 10 minutes, and 24 hours later chorionic villi were extracted; the other 30 cases were taken as the control group. Single-stranded DNA and double-stranded DNA in villus cells in all cases were isolated by the alkaline unwinding combined with hydroxylapatite chromatography, and were quantitatively detected using32 P-labeled Alu probe for dot-blotting hybridization. Results There was no significant difference in quantity and percentage in single-stranded DNA and double-stranded DNA between 2 groups (P＞0.05). 32 P-Alu probe could only hybridize with human DNA, and could detect DNA isolated from as few as 2.5 × 103 chorionic villus cells and 0.45 ng DNA in human leukocytes. Conclusion The results suggested that there were no DNA strand damages in human chorionic villus cells when the uterus was exposed to diagnostic ultrasound for 10 minutes. The method, 32P-Alu probe for dot-blotting hybridization, was even more specific, sensitive and accurate than conventional approaches.