Shear stress enhances DNA synthesis of immature Mks. (A-C) The BrdU⁺ percentage of all adherent and nonadherent Mks or (D-F) Mks with different ploidy classes (2N, 4N, and ≥ 8N) upon exposure to various shear-stress conditions. After shear-flow application, Mks were cultured in the presence of BrdU for a total of 4 hours. Cells were then harvested for CD41 and propidium iodide (DNA) staining and analyzed by flow cytometry. (A,D) At day 8, Mks were exposed to shear stress at level of 2.5 dyn/cm² for 0 (static control), 15, 30, 60, and 120 minutes. (B,E) At day 8, Mks were exposed to shear stress at 0 (static control), 1.5, 2.5, and 4.0 dyn/cm² for 30 minutes. (C,F) At days 8, 10, and 12, Mks were exposed to 2.5 dyn/cm² for 30 minutes. Error bars indicate standard error of mean (SEM) of 3 biological replicates. *P < .05; †P < .05 compared with corresponding static control. ns, not significant.