Soyasaponin Bb Attenuates Morphine Withdrawal-Induced Anxiety-Like Behaviors in Male Mice by Rescuing GSK-3β/Nrf2 Signaling.

OBJECTIVE: To examine the effect of Soyasaponin Bb on morphine withdrawal-induced anxiety-like behaviors in male mice and the corresponding mechanism. METHODS: The chronic intermittent escalating-dose morphine administration paradigm and spontaneous withdrawal were used to induce anxiety-like behaviors in male mice. Open field test (OFT) and elevated plus maze test (EPM) were used to evaluate anxiety-like behaviors. Soyasaponin Bb was intragastrically administered. Western blot was used to monitor the level of GSK-3β, Nrf2, and superoxidase dismutase in the basolateral amygdala (BLA). Virus-mediated gene overexpression and knockdown were used to manipulate the expression of GSK-3β and Nrf2 in the BLA. Two-way analysis of variance followed by Tukey's test were used to make comparisons for the experiments between four groups. Student's t-test was used to make comparisons for the experiments between two groups. RESULTS: Intragastric administration of Soyasaponin Bb attenuated morphine withdrawal-induced anxiety-like behaviors in male mice. Soyasaponin Bb rescued GSK-3β/Nrf2 signaling in the BLA in morphine withdrawn mice. Overexpression of GSK-3β in the BLA was sufficient to induce anxiety-like behaviors in male mice. Knockdown of GSK-3β in the BLA attenuated anxiety-like behaviors in male mice. Knockdown of Nrf2 in the BLA was sufficient to induce anxiety-like behaviors in male mice. CONCLUSION: Soyasaponin Bb could play anxiolytic effect by regulating GSK-3β/Nrf2 signaling and inhibition of GSK-3β in the BLA may represent a novel therapeutic approach to morphine addiction and anxiety disorders.