Adult neurogenesis: a real hope or a delusion?

Sleep rebound leads to marked recovery of prolonged sleep deprivation-induced adversities in the stress response and hippocampal neuroplasticity of male rats

BACKGROUND

Sleep disturbances are not only frequent symptoms, but also risk factors for major depressive disorder. We previously reported that depressed patients who experienced "Hypersomnia" showed a higher and more rapid response rate under paroxetine treatment, but the underlying mechanism remains unclear. The present study was conducted to clarify the beneficial effects of sleep rebound through an experimental "Hypersomnia" rat model on glucocorticoid and hippocampal neuroplasticity associated with antidepressive potency.

METHODS

Thirty-four male Sprague-Dawley rats were subjected to sham treatment, 72-h sleep deprivation, or sleep deprivation and subsequent follow-up for one week. Approximately half of the animals were sacrificed to evaluate adrenal weight, plasma corticosterone level, hippocampal content of mRNA isoforms, and protein of the brain-derived neurotrophic factor (Bdnf) gene. In the other half of the rats, Ki-67- and doublecortin (DCX)-positive cells in the hippocampus were counted via immunostaining to quantify adult neurogenesis.

RESULTS

Prolonged sleep deprivation led to adrenal hypertrophy and an increase in the plasma corticosterone level, which had returned to normal after one week follow-up. Of note, sleep deprivation-induced decreases in hippocampal Bdnf transcripts containing exons II, IV, VI, and IX and BDNF protein levels, Ki-67-(+)-proliferating cells, and DCX-(+)-newly-born neurons were not merely reversed, but overshot their normal levels with sleep rebound.

LIMITATIONS

The present study did not record electroencephalogram or assess behavioral changes of the sleep-deprived rats.

CONCLUSIONS

The present study demonstrated that prolonged sleep deprivation-induced adversities are reversed or recovered by sleep rebound, which supports "Hypersomnia" in depressed patients as having a beneficial pharmacological effect.

A randomized controlled trial of mindfulness-based cognitive therapy for major depressive disorder in undergraduate students: Dose- response effect, inflammatory markers and BDNF

To examine the dose-response effect of mindfulness-based cognitive therapy (MBCT) for college students with major depressive disorder (MDD), a randomized control trial with MBCT and a wait-list (WL) group was performed. All participants were invited to self-administer a set of questionnaires at baseline, mid-intervention (4th week), and post-intervention (8th week) by the 9-item Patient Health Questionnaire (PHQ-9), the 7-item Generalized Anxiety Disorder scale (GAD-7), the Pittsburgh Sleep Quality Index (PSQI), the Five Facet Mindfulness Questionnaire (FFMQ), the Self-Compassion Scale (SCS). The serum levels of IL-1β, IL-6, IL-8, TNF-α, BDNF were detected at baseline and post-intervention. After intervention, the scores of PHQ-9, GAD-7, PSQI, and the levels of IL-1β, IL-6, IL-8 and TNF-α in the MBCT were significantly lower than those in WL group, and total scores of FFMQ, SCS, and the level of BDNF were significantly higher than those in WL group. In MBCT group, daily practice time and session numbers positively related to reduction rates of PHQ-9, GAD-7 and PSQI at post-intervention. The reduction rate of PHQ-9, GAD-7 and PSQI at post-intervention in the completers were higher significantly than those in the partial attendees. These findings suggested MBCT is effective for MDD, and the intervention has a dose-response effect. TRIAL REGISTRATION: Registration number is [ChiCTR2100044309].