Dexiang Liu

Chronic ketamine exposure induces permanent impairment of brain functions in adolescent cynomolgus monkeys

Ketamine, a non‐competitive N‐methyl‐D‐aspartic acid receptor antagonist, has emerged as an increasingly popular drug among young drug abusers worldwide. Available evidence suggests that ketamine produces acute impairments of working, episodic and semantic memory along with psychotogenic and dissociative effects when a single dose is given to healthy volunteers. However, understanding of the possible chronic effects of ketamine on behavior, cognitive anomalies and neurochemical homeostasis is still incomplete. Although previous human studies demonstrate that ketamine could impair a range of cognitive skills, investigation using non‐human models would permit more precise exploration of the neurochemical mechanisms which may underlie the detrimental effects. The current study examined the abnormalities in behavior (move, walk, jump and climb) and apoptosis of the prefrontal cortex using terminal deoxynucleotidyl transferase‐mediated biotinylated dUTP nick end labeling (TUNEL) and apoptotic markers, including Bax, Bcl‐2 and caspase‐3 in adolescent male cynomolgus monkeys (Macaca fascicularis) after 1 or 6 months of sub‐anesthetic ketamine administration (1 mg/kg, i.v.). Results showed that ketamine decreased locomotor activity and increased cell death in the prefrontal cortex of monkeys with 6 months of ketamine treatment when compared with the control monkeys. Such decreases were not found in the 1‐month ketamine‐treated group. Our study suggested that ketamine administration of recreational dose in monkeys might produce permanent and irreversible deficits in brain functions due to neurotoxic effects, involving the activation of apoptotic pathways in the prefrontal cortex.

Long-term effects of early adolescent stress: dysregulation of hypothalamic–pituitary–adrenal axis and central corticotropin releasing factor receptor 1 expression in adult male rats

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder caused by traumatic experiences. Studies have found that exposure to early stressful events is a risk factor for developing PTSD. However, a limited number of studies have explored the effects of traumatic stress in early adolescence on behavior, hypothalamic-pituitary-adrenal (HPA) axis function, central corticotropin releasing factor receptor 1 (CRFR1) expression and the relative vulnerability of PTSD in adulthood. The current study aims to explore these issues using inescapable electric foot shock to induce a PTSD model in early adolescent rats. Meanwhile, running on a treadmill for six weeks and administration of the antagonist with 3.2mg/kg/day of CP-154, 526 for 14 consecutive days were used as therapeutic measures. Presently, the stress (S) group showed more anxiety and depression in the open field (OF) test and elevated plus maze (EPM) test, memory damage in the Y maze test, decreased basal CORT level, increased DEX negative feedback inhibition and exacerbated and longer-lasting reaction to CRH challenge in the DEX/CRH test compared with the control group. Central CRFR1 expression was also changed in the S group, as evidenced by the increased CRFR1 expression in the hypothalamus, amygdala and the prefrontal cortex (PFC). However, treadmill exercise alleviated early adolescent stress-induced behavior abnormalities and improved the functional state of the HPA axis, performing a more powerful effect than the CRFR1 antagonist CP-154, 526. Additionally, this study revealed that the alteration of central CRFR1 expression might play an important role in etiology of PTSD in adulthood.

Resveratrol exerts antidepressant properties in the chronic unpredictable mild stress model through the regulation of oxidative stress and mTOR pathway in the rat hippocampus and prefrontal cortex

Depression is one of the most common neuropsychiatric disorders and has been associated with oxidative stress and brain protein alterations. Resveratrol is a natural polyphenol enriched in Polygonum cuspidatum and has diverse biological activities including potent antidepressant-like effects. The present study attempts to explore the mechanisms underlying the antidepressant-like action of resveratrol by measuring oxidative stress parameters and phosphorylation of AKT/mTOR pathway in the rat hippocampus and prefrontal cortex (PFC) exposed to the chronic unpredictable mild stress (CUMS). Male Wistar rats were subjected to CUMS protocol for a period of 4 weeks to induce depressive-like behavior. The results showed that resveratrol treatment (80 mg/kg/i.p. 4 weeks) significantly reversed the CUMS-induced behavioral abnormalities (reduced sucrose preference, increased immobility time and decreased locomotor activity) and biochemical changes (increased lipid peroxidation and decreased superoxide dismutase). Additionally, CUMS exposure significantly decreased phosphorylation of Akt and mTOR in the hippocampus and PFC, while resveratrol treatment normalized these parameters. In conclusion, our study showed that resveratrol exerted antidepressant-like effects in CUMS rats, which was mediated in part by its antioxidant action, up-regulation of phosphor-Akt and mTOR levels in the hippocampus and PFC.

Resveratrol reverses chronic restraint stress-induced depression-like behaviour: Involvement of BDNF level, ERK phosphorylation and expression of Bcl-2 and Bax in rats

Chronic stress occurs in everyday life and induces depression-like behaviors, associated with proteins alterations and apoptosis in brain. Resveratrol is a natural polyphenol enriched in polygonum cuspidatum and has diverse biological activities, including potent antidepressant-like effects. The aim of this study was to determine whether resveratrol administration influences chronic restraint stress (CRS) - induced depression-like behaviors and explores underlying mechanisms. Male Wistar rats were subjected to CRS protocol for a period of 3 weeks to induce depressive-like behavior. The results showed that resveratrol (80mg/kg/i.p) administrated for 3 weeks significantly reversed the CRS-induced behavioral abnormalities (reduced sucrose preference and increased immobility time) in stressed rats. CRS exposure significantly decreased BDNF levels and phosphorylation of extracellular signal-regulated kinase (pERK) in hippocampus and prefrontal cortex (PFC), accompanied by decreased Bcl-2 mRNA expression and increased Bax mRNA expression, while resveratrol treatment normalized these levels. All of these effects of resveratrol were essentially identical to that observed with fluoxetine. In conclusion, our studies showed that resveratrol exerted antidepressant-like effects in CRS rats, mediated in part by the apoptotic machinery and up-regulating BDNF and pERK levels in the brain region.

Family functioning, marital satisfaction and social support in hemodialysis patients and their spouses.

A growing number of studies have demonstrated the importance of marital quality among patients undergoing medical procedures. The aim of the study was to expand the literature by examining the relationships between stress, social support and family and marriage life among hemodialysis patients. A total of 114 participants, including 38 patients and their spouses and 38 healthy controls, completed a survey package assessing social support, stress, family functioning and marital satisfaction and quality. We found that hemodialysis patients and spouses were less flexible in family adaptability compared with the healthy controls. Patients and spouses had more stress and instrumental social support compared with healthy people. Stress was negatively associated with marital satisfaction. Instrumental support was not associated with family or marital outcomes. The association between marital quality and support outside of family was positive in healthy individuals but was negative in patients and their spouses. Family adaptability was positively associated with support within family as perceived by patients and positively associated with emotional support as perceived by spouses. In conclusion, findings suggest that social support may promote adjustment depending on the source and type. Future research should pay more attention to the types and sources of social support in studying married couples.

The Personality and Psychological Stress Predict Major Adverse Cardiovascular Events in Patients With Coronary Heart Disease After Percutaneous Coronary Intervention for Five Years

AbstractTo investigate the effects of personality type and psychological stress on the occurrence of major adverse cardiovascular events (MACEs) at 5 years in patients with coronary artery disease (CAD) after percutaneous coronary intervention (PCI).Two hundred twenty patients with stable angina (SA) or non-ST segment elevation acute coronary syndrome (NSTE-ACS) treated with PCI completed type A behavioral questionnaire, type D personality questionnaire, Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS), Trait Coping Style Questionnaire (TCSQ), and Symptom Checklist 90 (SCL-90) at 3 days after PCI operation. Meanwhile, biomedical markers (cTnI, CK-MB, LDH, LDH1) were assayed. MACEs were monitored over a 5-year follow-up.NSTE-ACS group had higher ratio of type A behavior, type A/D behavior, and higher single factor scores of type A personality and type D personality than control group and SAP group. NSTE-ACS patients had more anxiety, depression, lower level of mental health (P < 0.05; P < 0.01), more negative coping styles and less positive coping styles. The plasma levels of biomedical predictors had positive relation with anxiety, depression, and lower level of mental health. Type D patients were at a cumulative increased risk of adverse outcome compared with non-type D patients (P < 0.05).Patients treated with PCI were more likely to have type A and type D personality and this tendency was associated with myocardial injury. They also had obvious anxiety, depression emotion, and lower level of mental health, which were related to personality and coping style. Type D personality was an independent predictor of adverse events.

FKBP5 and specific microRNAs via glucocorticoid receptor in the basolateral amygdala involved in the susceptibility to depressive disorder in early adolescent stressed rats

Exposure to stressful events induces depressive-like symptoms and increases susceptibility to depression. However, the molecular mechanisms are not fully understood. Studies reported that FK506 binding protein51 (FKBP5), the co-chaperone protein of glucocorticoid receptors (GR), plays a crucial role. Further, miR-124a and miR-18a are involved in the regulation of FKBP5/GR function. However, few studies have referred to effects of early life stress on depressive-like behaviours, GR and FKBP5, as well as miR-124a and miR-18a in the basolateral amygdala (BLA) from adolescence to adulthood. This study aimed to examine the dynamic alternations of depressive-like behaviours, GR and FKBP5, as well as miR-124a and miR-18a expressions in the BLA of chronic unpredictable mild stress (CUMS) rats and dexamethasone administration rats during the adolescent period. Meanwhile, the GR antagonist, RU486, was used as a means of intervention. We found that CUMS and dexamethasone administration in the adolescent period induced permanent depressive-like behaviours and memory impairment, decreased GR expression, and increased FKBP5 and miR-124a expression in the BLA of both adolescent and adult rats. However, increased miR-18a expression in the BLA was found only in adolescent rats. Depressive-like behaviours were positively correlated with the level of miR-124a, whereas GR levels were negatively correlated with those in both adolescent and adult rats. Our results suggested FKBP5/GR and miR-124a in the BLA were associated with susceptibility to depressive disorder in the presence of stressful experiences in early life.

Dynamic Alterations of miR-34c Expression in the Hypothalamus of Male Rats after Early Adolescent Traumatic Stress

Several types of microRNA (miRNA) overexpression in the brain are associated with stress. One of the targets of miR-34c is the stress-related corticotrophin releasing factor receptor 1 mRNA (CRFR1 mRNA). Here we will probe into the short-term effect and long-term effect of early adolescent traumatic stress on the expression of miR-34c and CRFR1 mRNA. Traumatic stress was established by electric foot shock for six consecutive days using 28-day rats. The anxiety-like behaviors, memory damage, CRFR1 protein, CRFR1 mRNA, and miR-34c expression were detected in our study. The results of our study proved that exposure to acute traumatic stress in early adolescent can cause permanent changes in neural network, resulting in dysregulation of CRFR1 expression and CRFR1 mRNA and miR-34c expression in hypothalamus, anxiety-like behavior, and memory impairment, suggesting that the miR-34c expression in hypothalamus may be an important factor involved in susceptibility to PTSD.

Therapeutic effects of L-Cysteine in newborn mice subjected to hypoxia-ischemia brain injury via the CBS/H2S system: Role of oxidative stress and endoplasmic reticulum stress

Neonatal hypoxic-ischemic (HI) injury is a major cause of neonatal death and neurological dysfunction. H2S has been shown to protect against hypoxia-induced injury and apoptosis of neurons. L-Cysteine is catalyzed by cystathionine-β-synthase (CBS) in the brain and sequentially produces endogenous H2S. The present study was designed to investigate whether L-Cysteine could attenuate the acute brain injury and improve neurobehavioral outcomes following HI brain injury in neonatal mice by releasing endogenous H2S. L-Cysteine treatment significantly attenuated brain edema and decreased infarct volume and neuronal cell death, as shown by a decrease in the Bax/Bcl-2 ratio, suppression of caspase-3 activation, and reduced phosphorylation of Akt and ERK at 72 h after HI. Additionally, L-Cysteine substantially up-regulated NF-E2-related factor 2 and heme oxygenase-1 expression. L-Cysteine also decreased endoplasmic reticulum (ER) stress-associated pro-apoptotic protein expression. Furthermore, L-Cysteine had long-term effects by protecting against the loss of ipsilateral brain tissue and improving neurobehavioral outcomes. Importantly, pre-treatment with a CBS inhibitor significantly attenuated the neuroprotection of L-Cysteine on HI insult. Thus, L-Cysteine exerts neuroprotection against HI-induced injury in neonates via the CBS/H2S pathway, mediated in part by anti-apoptotic effects and reduced oxidative stress and ER stress. Thus, L-Cysteine may be a promising treatment for HI.

l-Cysteine suppresses hypoxia-ischemia injury in neonatal mice by reducing glial activation, promoting autophagic flux and mediating synaptic modification via H2S formation

We previously reported that l-Cysteine, an H2S donor, significantly alleviated brain injury after hypoxia-ischemic (HI) injury in neonatal mice. However, the mechanisms underlying this neuroprotective effect of l-Cysteine against HI insult remain unknown. In the present study, we tested the hypothesis that the protective effects of l-Cysteine are associated with glial responses and autophagy, and l-Cysteine attenuates synaptic injury as well as behavioral deficits resulting from HI. Consistent with our previous findings, we found that treatment with l-Cysteine after HI reduced early brain injury, improved behavioral deficits and synaptic damage, effects which were associated with an up-regulation of synaptophysin and postsynaptic density protein 95 expression in the lesioned cortex. l-Cysteine attenuated the accumulation of CD11b+/CD45high cells, activation of microglia and astrocytes and diminished HI-induced increases in reactive oxygen species and malondialdehyde within the lesioned cortex. In addition, l-Cysteine increased microtubule associated protein 1 light chain 3-II and Beclin1 expression, decreased p62 expression and phosphor-mammalian target of rapamycin and phosphor-signal transducer and activator of transcription 3. Further support for a critical role of l-Cysteine was revealed from results demonstrating that treatment with an inhibitor of the H2S-producing enzyme, amino-oxyacetic acid, reversed the beneficial effects of l-Cysteine described above. These results demonstrate that l-Cysteine effectively alleviates HI injury and improves behavioral outcomes by inhibiting reactive glial responses and synaptic damage and an accompanying triggering of autophagic flux. Accordingly, l-Cysteine may provide a new a therapeutic approach for the treatment of HI via the formation of H2S.