Antidepressant, anti-inflammatory, and antioxidant effects of electroacupuncture through sonic hedgehog-signaling pathway in a rat model of poststroke depression

Abstract

Background: Poststroke depression (PSD) is the most frequent psychological sequela after stroke. Electroacupuncture (EA) treatment is effective for PSD. The study aimed at clarifying the mechanisms of EA's antidepressant effects in a PSD rat model. Methods: We used middle cerebral artery occlusion to establish the rat model of PSD. Tests of sucrose preference and locomotor activity were performed to examine depressive-like behaviors. We measured malondialdehyde, GSH, SOD, IL6, IL1β, TNFα, and 5HT with ELISA. The hippocampal Shh-signaling pathway was assessed by Western blot. Results: EA significantly decreased sucrose preference and locomotor activities of PSD rats, reduced IL6, TNFα, increased GSH, and upregulated 5HT, and also slightly reduced IL1β and malondialdehyde, all of which were measured with ELISA. The Shh-signaling pathway assessed by Western blotting was activated by EA. Those changes were inhibited by the Shh-pathway inhibitor cyclopamine. Conclusion: EA effectively alleviated depressive-like behaviors in PSD by suppressing inflammation and oxidative stress through activation of the Shh-signaling pathway.

Keywords: 5HT; electroacupuncture; inflammation; oxidative stress; poststroke depression; sonic hedgehog–signaling pathway.

Figure 1

Protocol for the experiment. All other experimental procedures were done after the interventions. Rats were killed after the last test. Abbreviations: SPT, sucrose-preference test; LA, locomotor activity; SAC, sacrifice; MCAO, middle cerebral artery occlusion; WB, Western blot.

Figure 2

Improvement in depressive-like behaviors of PSD. (A) Effect of EA treatment on SPT; (B) changes in locomotion activity after EA treatment. Values are presented as means ± SEM, with eight rats in each group. **P<0.01 versus sham group; ***P<0.001 versus sham group; ^##P<0.01 versus PSD group; ^###P<0.001 versus PSD group; ^&&P<0.01 versus EA group; ^%P<0.05 versus EA + Cyc group. Abbreviations: PSD, poststroke depression; EA, electroacupuncture; SPT, sucrose-preference test; Cyc, cyclopamine.

Figure 3

Alleviation of oxidative stress and inflammation. (A–F) Comparisons of SOD, GSH, MDA, IL6, TNFα, and IL1β levels in sham, PSD, EA + PSD, EA + Cyc, EA + vehicle, and Flu groups by ELISA. Values are presented as means ± SEM, with eight rats in each group. **P<0.01 versus sham group; ^#P<0.05 versus PSD group; ^###P<0.001 versus PSD group. Abbreviations: MDA, malondialdehyde; PSD, poststroke depression; EA, electroacupuncture; Cyc, cyclopamine; Flu, fluoxetine.

Figure 4

Changes in 5HT levels. Comparison of 5HT levels in sham, PSD, EA + PSD, EA + Cyc, EA + vehicle, and Flu groups by ELISA. Values are presented as means ± SEM, with eight rats in each group. **P<0.01 versus sham group; ^##P<0.05 versus PSD group; ^&P<0.05 versus EA group; ^%P<0.05 versus EA + Cyc group. Abbreviations: PSD, poststroke depression; EA, electroacupuncture; Cyc, cyclopamine; Flu, fluoxetine.

Figure 5

Regulation of Shh-signaling pathway. (A) Immunoblot analysis for expression of Shh, Gli1, Smo, Ptch1, and β-actin in sham, PSD, EA + PSD, EA + Cyc, EA + vehicle, and Flu groups. (B–E) Comparisons of Shh, Gli1, Smo, and Ptch1 levels in six groups by Western blot. Values are presented as means ± SEM, with eight rats in each group. *P<0.05 versus PSD group; **P<0.01 versus PSD group; ***P<0.001 versus PSD group; ^#P<0.05 versus PSD group; ^##P<0.01 versus PSD group; ^&P<0.05 versus EA group; ^%P<0.05 versus the EA + Cyc group. Abbreviations: PSD, poststroke depression; EA, electroacupuncture; Cyc, cyclopamine; Flu, fluoxetine.