Antidepressant, anti-amnesic and vasoprotective effect of Bombax costatum Pellegr. & Vuillet aqueous stem bark extract on chronic mild unpredictable stress induced in rat

Unpredictable chronic mild stress induced anxio-depressive disorders and enterobacteria dysbiosis: Potential protective effects of Detariummicrocarpum

ETHNOPHARMACOLOGICAL RELEVANCE

Detarium microcarpum Guill. & Perr. is used traditionally in Far North Cameroun to treat stomach aches, anxiety, epilepsy, and other mental disorders.

AIM OF THE STUDY

Evaluate the anxiolytic and antidepressant-like effects of D. microcarpum (DM) in unpredictable chronic mild stress (UCMS) model of depression in male rats and its impact on fecal enterobacteria of stressed rats.

MATERIALS AND METHODS

Rats were handled daily (control) or subjected to the UCMS procedure for 42 days. Anxiety-like behaviors were assessed using the light and dark box test (LBD) and the open field test (OFT). Depressive-like behaviors were assessed using the forced swimming test (FST), the sucrose preference test (SPT), and the novelty suppressed feeding test (NSFT). Feces were then collected, followed by blood, brain, and duodenum sections after sacrifice. Monoamine levels, pro-inflammatory cytokines, oxidative stress factors, and nitrosative stress were assessed. Feces were introduced into Hectoen enteric agar for the identification of enterobacteria. An in vitro growth test was performed.

RESULTS

The DM ethanolic extract has significantly increased the time spent in the light box, in the LBD, and in the center area of the OFT. Moreover, the extract has significantly reduced the preference for sucrose in the SPT, the time of immobility in the FST, and the latency period to consume the pet in the NSFT. DM extract has significantly reduced serum cortisol levels. It also significantly decreased the pro-inflammatory cytokines TNF-α and Il-1β in both brain and duodenum homogenate. DM has increased the brain's serotonin, GABA, and dopamine levels. The DM extract also decreased the MDA and nitrite levels. It also increased the SOD and CAT activities in both brain and duodenal homogenate. Histologically, the DM extract restored the cell's density in hippocampi sections and prevented gut inflammation and peroxidation characterizing leaky gut syndrome. DM extract has no effect on the growth of enterobacteria species isolated in vitro.

CONCLUSION

The ethanolic extract of DM would have anxiolytic and antidepressant effects via the modulation of the HPA axis, brain antioxidant enzyme activities, inflammation, and nitrosative stress. Moreover, it could act by preventing leaky gut syndrome.

Cerebrovascular dysfunction and depressive symptoms in preclinical models: insights from a scoping review

Although existing literature supports associations between cerebrovascular dysfunction and the emergence of depression and depressive symptoms, relatively little is known about underlying mechanistic pathways that may explain potential relationships. As such, an integrated understanding of these relationships in preclinical models could provide insight into the nature of the relationship, basic mechanistic linkages, and areas in which additional investment should be targeted. This scoping review was conducted in MEDLINE, EMBASE, and Scopus to outline the relationship between depressive symptoms and cerebrovascular dysfunction in preclinical animal models with an additional focus on the areas above. From 3,438 articles initially identified, 15 studies met the inclusion criteria and were included in the review. All studies reported a positive association between the severity of markers for cerebrovascular dysfunction and that for depressive symptoms in rodent models and this spanned all models for either pathology. Specific mechanistic links between the two such as chronic inflammation, elevated vascular oxidant stress, and altered serotonergic signaling were highlighted. Notably, almost all studies addressed outcomes in male animals, with a near complete lack of data from females, and there was little consistency in terms of how cerebrovascular dysfunction was assessed. Across nearly all studies was a lack of clarity for any "cause and effect" relationship between depressive symptoms and cerebrovascular dysfunction. At this time, it is reasonable to conclude that a correlative relationship clearly exists between the two, and future investigation will be required to parse out more specific aspects of this relationship.NEW & NOTEWORTHY This scoping review presents a structured evaluation of all relevant existing literature linking cerebral vasculopathy to depressive symptom emergence in preclinical models. Results support a definite connection between vascular dysfunction and depressive symptoms, highlighting the importance of chronic elevations in inflammation and oxidant stress, and impaired serotonergic signaling. The review also identified significant knowledge gaps addressing male versus female differences and limited clear mechanistic links between cerebral vasculopathy and depressive symptoms.

Cashew (Anacardium occidentale) Extract: Possible Effects on Hypothalamic-Pituitary-Adrenal (HPA) Axis in Modulating Chronic Stress

Depression presents a significant global health burden, necessitating the search for effective and safe treatments. This investigation aims to assess the antidepressant effect of the hydroethanolic extract of Anacardium occidentale (AO) on depression-related behaviors in rats. The depression model involved 42 days of unpredictable chronic mild stress (UCMS) exposure and was assessed using the sucrose preference and the forced swimming (FST) test. Additionally, memory-related aspects were examined using the tests Y-maze and Morris water maze (MWM), following 21 days of treatment with varying doses of the AO extract (150, 300, and 450 mg/kg) and Imipramine (20 mg/kg), commencing on day 21. The monoamines (norepinephrine, serotonin, and dopamine), oxidative stress markers (MDA and SOD), and cytokines levels (IL-1β, IL-6, and TNF-α) within the brain were evaluated. Additionally, the concentration of blood corticosterone was measured. Treatment with AO significantly alleviated UCMS-induced and depressive-like behaviors in rats. This was evidenced by the ability of the extract to prevent further decreases in body mass, increase sucrose consumption, reduce immobility time in the test Forced Swimming, improve cognitive performance in both tests Y-maze and the Morris water maze by increasing the target quadrant dwelling time and spontaneous alternation percentage, and promote faster feeding behavior in the novelty-suppressed feeding test. It also decreased pro-inflammatory cytokines, corticosterone, and MDA levels, and increased monoamine levels and SOD activity. HPLC-MS analysis revealed the presence of triterpenoid compounds (ursolic acid, oleanolic acid, and lupane) and polyphenols (catechin quercetin and kaempferol). These results evidenced the antidepressant effects of the AO, which might involve corticosterone and monoaminergic regulation as antioxidant and anti-inflammatory activities.

Memory impairments in rodent depression models: A link with depression theories

More than 80% of depressed patients struggle with learning new tasks, remembering positive events, or concentrating on a single topic. These neurocognitive deficits accompanying depression may be linked to functional and structural changes in the prefrontal cortex and hippocampus. However, their mechanisms are not yet completely understood. We conducted a narrative review of articles regarding animal studies to assess the state of knowledge. First, we argue the contribution of changes in neurotransmitters and hormone levels in the pathomechanism of cognitive dysfunction in animal depression models. Then, we used numerous neuroinflammation studies to explore its possible implication in cognitive decline. Encouragingly, we also observed a positive correlation between increased oxidative stress and a depressive-like state with concomitant memory deficits. Finally, we discuss the undeniable role of neurotrophin deficits in developing cognitive decline in animal models of depression. This review reveals the complexity of depression-related memory impairments and highlights the potential clinical importance of gathered findings for developing more reliable animal models and designing novel antidepressants with procognitive properties.