Comparative study on TUNEL and Annexin v-FITC in detecting fibroblast apoptosis

Objective To compare the advantages and disadvantages of TUNEL and Annex in v-FITC with flow cytometry in detecting fibroblast apoptosis. Methods In vitro culture-tensile stimulation models of fibroblast were established using a multi-passage load adding system. Cyclic tensile stress was applied on the fibroblasts( the load was set for 12% surfaceelongation,with frequency of 10 cycles per minute. A cycle of stress comprised 3 s stretch /3 s relaxation) for 6,12,and 24 hours. At the same time,thenormal control group was established. The cell apoptosis was determined by TUNEL and Annex in v-FITC withflow cytometry,Results In the experimental group,nuclei stained buffy were detected as positive cells by TUNEL assay. Meanwhile the cells changed into smaller,rounder and nuclear condensation. But normal nuclei were not stained. Load adding significantly prolonged cell cycles. Flow cytometry results showed thatthe number of cells in G0 / G1 phase has notably increased in the experimental group,yet the S phase cells corresponding ratio decreased significantly,while in G2 / M phase there was an obvious change in the control group. DNA content in 6,12 h group was352. 0 ± 1. 0、301. 1 ± 1. 1respectively. There was significant prolongation than the control group( 255. 2 ± 1. 7),but the cell cycle has shortened in 24 h group( 303. 4 ± 10. 6) compared with 6 h group. Conclusions Annex in v-FITC withflow cytometry is more specific,while TUNEL assay is more sensitive. It is more precise to combine Annex in v-FITC with TUNEL