Fig. 1.

Apoptosis of CGCs after 12 hr of treatment with media containing 25 mm KCl and 10% serum (control,Ctrl), 25 mm KCl and no serum (K25−S), 5 mm KCl and 10% serum (K5+S), or 5 mm KCl and no serum (K5−S). A, Cells were stained with 5 μm calcein AM, which is deesterified into a fluorescent product by viable cells. i, Control;ii, K25−S; iii, K5+S; iv,K5−S. Scale bar, 20 μm. B, Cell viability was quantified by counting the number of fluorescent cells per randomly chosen 200× field. Data are represented as the percent-to-control average number of fluorescent cells + SEM (n = 9). ***p < 0.001 compared with Ctrl; ‡‡p < 0.01 compared with K25−S; ‡‡‡p < 0.001 compared with K25−S by ANOVA and one-tailed Tukey’s test.C, Genomic DNA was extracted and electrophoresed in 1.5% agarose. Internucleosomal fragmentation was most prominent in K5+S and K5−S samples, suggesting that cell death in these cultures is apoptotic. MW = 100 bp molecular weight ladder (Life Technologies).