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. 2015 Jun 10;35(11):1790–1803. doi: 10.1038/jcbfm.2015.126

Figure 2.

Figure 2

Effect of exendin-4 (Ex-4) and Ex-4-loaded poly(D,L-lactide-co-glycolide) microspheres (PEx-4) on carotid artery occlusion (CAO)-induced brain edema in control and diabetes mellitus (DM) rats. (A) The T2-weighted magnetic resonance imaging series revealed that marked brain edema (high signal intensity area) appeared in the CT1, CT2, and CT3 areas of the CAO and DM+CAO groups but not in the sham-operated control and DM rats. PEx-4 reduced brain edema areas in CAO and DM+CAO rats more effectively than Ex-4. (B) CAO and DM+CAO rats had a significantly (P<0.05) higher percentage of brain edema in the CT1, CT2, and CT3 areas in comparison with sham control rats. PEx-4 treatment decreased the brain edema percentage more significantly (P<0.05) than Ex-4 in the CT2 and CT3 areas of CAO rats and in the CT2 and CT3 areas of DM+CAO rats. (C) Green fluorescence of aquaporin 4 (AQP4) immunostaining in astrocytes was markedly observed in the CAO and CAO+DM groups. PEx-4 and Ex-4 reduced AQP4 expression in the DM+CAO group. (D) Cortical AQP4 expression was significantly enhanced in CAO and DM+CAO rats in comparison with control rats. DM+CAO rats had higher AQP4 expression than CAO rats. Ex-4 showed a non-significant tendency (P=0.37) to reduce AQP4 expression in DM+CAO rats. PEx-4 significantly reduced the cortical AQP4 expression in comparison with Ex-4 treatment. Group differences (n=6 each) were compared by one-way analysis of variance, followed by Tukey's multiple comparison tests. P<0.05 indicates a significant difference. *Different from control (Con); #different from DM; +different from CAO; adifferent from DM+CAO; bdifferent from the Ex-4-treated group.