Assessment of Cell Viability in Umbilical Cord Blood by Using 7-AAD/annexin V Dual Staining

ABSTRACT

BACKGROUND: The quality of cord blood largely depends on cell viability. Viability assessments using trypan blue or 7-aminoactinomycin (7-AAD) staining, which are commonly used methods, may not reflect early apoptosis of cord blood cells. We aimed to investigate early apoptosis in cord blood cells following elapsed time after collection using double staining with annexin V and 7-AAD and to compare the result with that of viability evaluation using trypan blue or 7-AAD staining. METHODS: Umbilical cord blood samples were obtained from 30 pregnant women at the time of delivery between July 2012 and March 2013. Viability of cord blood cells was determined at 0 (T0), 24, and 48 hr after collection by using trypan blue exclusion assay, 7-AAD staining, and 7-AAD/annexin V staining. RESULTS: Viabilities defined by 7-AAD/annexin V staining at T0, 24, and 48 hr after collection were respectively as follows total nucleated cells, 92.8+/-4.5%, 78.4+/-7.8%, and 65.5+/-8.1%; mononuclear cells, 94.4+/-1.7%, 90.8+/-4.2%, and 84.2+/-6.7%; and CD34-positive cells, 92.4+/-3.0%, 90.7+/-4.7%, and 89.3+/-7.0%. The viability using trypan blue was more than 90% until 48 hr after collection. CONCLUSIONS: The mean viability of total nucleated cells using 7-AAD/annexin V staining decreased to less than 80% at 24 hr after collection; however, the viability of CD34-positive cells was more than 85% until 48 hr. Our study's data will provide useful information for the assessing the quality of cord blood products.