Figure 6

Relationship between ASB activity and total sGAG following chloroquine exposure over 72 hours. Chloroquine (50 nM) was administered for 24 hours, the spent media removed, and fresh media without chloroquine was supplied at 24 and 48 hours. ASB activity (Panel A) and total sGAG (Panel B) were measured in spent media at 24, 48, and 72 hours, as shown. ASB activity rose from the nadir at 24 hours and returned to baseline by 72 hours (p < 0.001 at 24 and 48 hours; 1-way ANOVA with Tukey-Kramer post-test). Inversely, the sGAG content peaked at 24 hours and returned to baseline by 72 hours (p < 0.001 at 24 hours, p < 0.01 at 48 hours; 1-way ANOVA with Tukey-Kramer post-test). QPCR demonstrated less baseline mRNA expression of ASB in the IB3-1 cells than in the C38 cells (Panel C), and declines in both cell lines following exposure to chloroquine (50 μM × 24 hours). Cycle threshold of ASB was calculated in comparison to cycle threshold of β-actin, which varied only from 29.36 to 30.27.