Lithium chloride promotes neural functional recovery after local cerebral ischaemia injury in rats through Wnt signalling pathway activation

Associations of serum Dickkopf-1 levels with disease severity and 90-day Prognosis after spontaneous intracerebral hemorrhage: results from the prospective cohort study

Dickkopf-1 (DKK-1) may be involved in inflammatory response and secondary brain injury after acute brain injury. We gauged serum DKK-1 levels and further assessed its correlation with disease severity and investigated its predictive value for 90-day prognosis in patients with spontaneous intracerebral hemorrhage (sICH). Serum DKK-1 levels were measured in 128 sICH patients and 128 healthy controls. The severity of sICH was assessed using the Glasgow Coma Scale (GCS) scores and hematoma volumes. Poor prognosis was referred to as a Glasgow Outcome Scale (GOS) score of 1-3 at 90 days after stroke. Multivariate analysis was performed to identify associations of serum DKK-1 levels with disease severity, early neurological deterioration (END) and poor prognosis. Receiver operating characteristic curve (ROC) was built to investigate the prognostic predictive capability. The serum DKK-1 levels of patients were significantly higher than those of controls (median, 4.74 ng/mL versus 1.98 ng/mL; P < 0.001), and were independently correlated with hematoma volumes (ρ = 0.567, P < 0.001; t = 3.444, P = 0.001) and GCS score (ρ = -0.612, P < 0.001; t = -2.048, P = 0.043). Serum DKK-1 significantly differentiated patients at risk of END (area under ROC curve (AUC), 0.850; 95% confidence interval (CI), 0.777-0.907; P < 0.001) and poor prognosis (AUC, 0.830; 95% CI, 0.753-0.890; P < 0.001), which had similar prognostic ability, as compared to GCS scores and hematoma volumes. Subsequent Logistic regression model affirmed that GCS score, hematoma volume, and serum DKK-1 levels were independently associated with END and poor prognosis at 90 days after sICH. The models, which contained them, performed well using ROC curve analysis and calibration curve analysis. Serum DKK-1 levels are markedly associated with disease severity, END and 90-day poor prognosis in sICH. Hence, serum DKK-1 is presumed to be used as a potential prognostic biomarker of sICH.

VEGF overexpression in transplanted NSCs promote recovery of neurological function in rats with cerebral ischemia by modulating the Wnt signal transduction pathway

Neural stem cell transplantation is a good method to treat stroke, but the mechanism is still unclear. Therefore, this study aims to explore the regulatory mechanism of VEGF overexpression in transplanted NSCs to promote the recovery of neural function in ischemic rats by regulating Wnt signal transduction pathways. We amplified VEGF gene fragments by PCR and transfected them into NSCs with Ad5 adenovirus. Rat brain IRI model was established by MCAO method, and VEGF transfected NSCs (VEGF-NSCs) were transplanted 24 h after successful IRI model. One week after the transplant, cognitive function was assessed using a neurological deficit score; Brain injury was assessed by histopathology; Photochemical and ELISA methods were used to detect oxidative stress markers and inflammatory factors, respectively. Western blotting has been detected in molecules of the Wnt signaling pathway. The results showed that the transduced NSCs express VEGF at least for 14 days. VEGF-NSCs transplantation (VNT) improved spatial learning and memory in rats, and inhibited oxidative stress injury, inflammatory response, and histopathological injury. VNT also resulted in significant changes in the phosphorylation levels of β-catenin and GSK-3β proteins, ultimately triggering activation of the Wnt signal transduction pathway. These results suggest that the neuroprotective effects of VNT may be related to the regulation of the Wnt signal transduction pathway.

Sex difference affects fear extinction but not lithium efficacy in rats following fear-conditioning with respect to the hippocampal level of BDNF

In rodents, exposure to electrical shock and creating a strong fear memory using fear-conditioning model can induce PTSD-like behavior. In this study, we induced a fear-conditioning model in rats and investigated freezing (PTSD-like) behavior, 21 days after three shocks exposure (0.6 mA, 3 s, 30 seconds interval) in both male and female rats. Lithium was injected intraperitoneally (100 mg/kg) in three protocols: (1) 1 h after fear-conditioning (2) 1 h, 24 h, and 48 h after fear-conditioning (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning. Extinction training (20 sounds without shocks, 75 dB, 3 s, 30 seconds interval) was performed in three protocols: (1) 1 h after fear-conditioning (one session), (2) 1 h, 24 h, and 48 h after fear-conditioning (three sessions), (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning (five sessions). Forced swim test (FST) and hot plate were used to assess behavior. Results showed that lithium in all protocols had no effect on freezing behavior, FST, and pain subthreshold in all rats. Extinction training decreased freezing behavior, with more efficacy in females. In males, only 5-session training was effective, while in females all protocols were effective. Extinction training also altered pain perception and the results of FST, depending on the sessions and was different in males and females. Brain-derived neurotrophic factor (BDNF) mRNA level was increased in females following 3 and 5 sessions, and in males following 5 sessions extinction training. In conclusion, we suggested that there is a sex difference for the effect of extinction training on freezing behavior and BDNF mRNA level in a rat model of fear-conditioning.

Mood and behavior regulation: interaction of lithium and dopaminergic system

Lithium is one of the most effect mood-stabilizing drugs prescribed especially for bipolar disorder. Lithium has wide range effects on different molecular factors and neural transmission including dopaminergic signaling. On the other hand, mesolimbic and mesocortical dopaminergic signaling is significantly involved in the pathophysiology of neuropsychiatric disorders. This review article aims to study lithium therapeutic mechanisms, dopaminergic signaling, and the interaction of lithium and dopamine. We concluded that acute and chronic lithium treatments often reduce dopamine synthesis and level in the brain. However, some studies have reported conflicting results following lithium treatment, especially chronic treatment. The dosage, duration, and type of lithium administration, and the brain region selected for measuring dopamine level were not significant differences in different chronic treatments used in previous studies. It was suggested that lithium has various mechanisms affecting dopaminergic signaling and mood, and that many molecular factors can be involved, including brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), β-catenin, protein kinase B (Akt), and glycogen synthase kinase-3 beta (GSK-3β). Thus, molecular effects of lithium can be the most important mechanisms of lithium that also alter neural transmissions including dopaminergic signaling in mesolimbic and mesocortical pathways.