siRNAs, not transfection alone, induces host cell toxicity over time.

<p>(A) At 24, 48, 72 and 96 hours post transfection, medium from HeLa cells transfected with 25 nM siRNA pools was mixed with an equal volume CytoToxONE assay reagent. Fluorescence of samples was measured and data plotted as a percentage of the maximum LDH release obtained from lysed cells (% max release). (B) HeLa cells were treated with transfection medium alone (white) or transfected with AllStars Negative Control (black) or AllStars Hs Cell Death Control (blue) siRNAs. At the indicated times, cells were trypsinized and the number of viable cells determined by trypan blue exclusion. Asterisks indicate a significant (p<0.05) increase from negative siRNA wells (A) or decrease from no siRNA control wells (B) at the corresponding timepoint.