Figure 4. Statins stimulate neurite elongation from spiral ganglion neurons.

(a–f) Examples of cumulative percent histograms of cultures from 6 separate platings. SEM from quadruplicate wells (gray) are plotted for each treatment. Histograms of cultures with tested compounds (black) are plotted atop those from cultures treated with DMSO or water (negative controls) and H1152 (positive control), green. The negative control graphs cannot be seen because the graphs from cultures treated with chemical compounds overlie them. (a–e) Represent a total of 200 tested compounds (5 dissections) assayed in medium without BMP4. (f) represents 40 compounds assayed in medium with BMP4. One compound, cerivastatin (red) causes a shift to the right of the histograms in both media, indicating populations of longer neurites. (a–f) black arrows, edges of the hidden DMSO control graph; red arrows, edges of the hidden water control graph. (g) Average neurite lengths of the 10 longest neurites from quadruplicate wells of 5 experiments. D, DMSO; W, water; H, H1152; C, Cerivastatin. Average lengths in H1152 and Cerivastatin cultures are longer than those in water or DMSO. Statistical analysis by ANOVA. **p < .01, H1152 compared to water. **p < .001 Cerivastatin compared to DMSO. (h) Average median neurite lengths from quadruplicate cultures treated with the indicated statins, depicted at their lowest effective concentrations. All tested statins, except pravastatin, increase neurite lengths at concentrations below 10 μM. *p < .05; **p < .01 There is no statistically significant change in neurite length in cultures treated with pravastatin up to 25 μM.