Figure 2.

AZT reduces neurosphere size. Single-cell dissociates of primary postnatal SEZ form neurospheres within 10 days in vitro. AZT (0, 0.3, or 30μM) was added to the culture medium for 1, 3, or 10 days beginning on in vitro day 1, and neurospheres were quantified and measured on in vitro day 11. (A) Representative untreated control neurospheres on day 11. (Inset in A) Representative day 11 neurospheres treated with 30 μM AZT for 3 days. AZT reduces neurosphere size in both a concentration- and time-dependent manner (B–D). With increasing exposure time and increasing dose there is a shift in the distribution of neurosphere sizes. While total neurosphere number remains constant among the control and treated groups, AZT induces an increase in smaller neurospheres at the expense of larger neurospheres. Notice the increasing height of the yellow bar (small neurospheres with a diameter less than 40 μM) and a corresponding decrease in the height of the blue and green bars (medium and large neurospheres, respectively). The cultures treated with 0.3 μM AZT show a trend toward smaller neurospheres that does not reach statistical significance compared to untreated controls. Cultures treated with 30 μM AZT show clearly significant loss of medium and large neurospheres at days 3 and 10. One-Way ANOVA, Dunnett's Multiple Comparison Test of significance; N = 3 for all groups; ^*p < 0.05. Asterisks indicate a significant difference as compared to the corresponding size range of neurospheres in matched, untreated cultures. Error bars represent standard deviation.