Qualitative and Quantitative Analysis of the Fate of DNA in the Digestive Tract of Mice

Abstract

Objective: Qualitative and quantitative examination of DNA degradation during the digestion process in the mouse gut through PCR, qPCR and short tandem repeat (STR) analysis.Methods: Human blood leukocytes were gavage into the digestive tract of mice. GAPDH, TH01, TPOX and D7S820 genes in the contents of the stomach and small intestine were analyzed through PCR and qPCR at various time pre- and post-gavage. Through STR analysis, 21 human genomic DNA loci were analyzed. The half-life of DNA degradation, and the relationship between the average peak area and digestion time were determined.Results: The PCR results showed DNA bands at pre-gavage (0 min) and post-gavage (40, 80 and 120 min) from the mouse stomach contents, whereas no DNA bands from small intestinal chyme were observed after gavage. The qPCR results revealed significant decrease in DNA concentrations during 40-120 minutes in mouse stomach after gavage. At 120 min, 85.62±8.10% of the DNA was degraded while the half-life of exogenous DNA degradation in mouse stomach was 70.50±5.46 min. At various time of digestion , almost no target genes were detected in the mouse small intestinal chyme. STR analysis showed a decrease in allele numbers with the advancement of bowl in the small intestine of mice.Conclusions: The degradation of exogenous DNA was higher in mouse stomach during first two hours while almost complete degradation was noted in the small intestine of mice within 40 min.