Figure 4.

Aquaporin-4 western blotting. Immunoreactivity signal at ~42 kD corresponds to β-actin, and ~30-32 kD corresponds to aquaporin-4. Western blots from the periventricular region of interest are shown as example. Two of the periventricular samples (one control and one two day) did not meet the minimum total protein level for western blotting, and therefore data from these two rats could not be obtained. Densitometry of ECL films was performed using QuantityOne software (Bio-Rad Laboratories). Aquaporin-4 signal was normalized against the β-actin signal. Relative aquaporin-4 expression values for each ROI are presented as box plots (median, interquartile range and total range). At day two a significant (Kruskal-Wallis) decrease compared to control in aquaporin-4 expression was found in both periventricular region (control: 1.00, 0.95-1.04, two day: 0.78, 0.63-0.084, p < 0.05) and cortex (control: 1.00, 0.93-1.14, two day: 0.81, 0.67-0.97, p < 0.05). Expression was normalized after one week, but after two weeks we found significantly increased periventricular expression (control: 1.00, 0.88-1.21; two weeks: 1.40, 1.27-1.64, p < 0.05). No significant changes were found in the periaqueductal region.