BDNF Overexpression Exhibited Bilateral Effect on Neural Behavior in SCT Mice Associated with AKT Signal Pathway

Effect of prior exposure to enriched environment on cellular apoptosis after experimental stroke

BACKGROUND

Growing evidence, including our previous studies, has demonstrated that an enriched environment (EE) after cerebral ischemia/reperfusion (I/R) injury improves neurofunctional recovery in rats. However, whether EE exposure prior to injury could play a neuroprotective role in stroke has seldom been investigated. In this study, we examined the neuroprotective effects of prior exposure to EE and investigated the potential anti-apoptotic effect in rats after cerebral I/R injury.

METHODS AND RESULTS

Rats were housed in EE or standard conditions (SC) for four weeks and then randomly assigned to receive 120 min of right middle cerebral occlusion (MCAO) or sham operation. Based on the housing environment and the procedure they underwent, the rats were divided into the following three groups: preischemic EE + MCAO (PIEE), preischemic SC + MCAO (PISC) and preischemic SC + sham-operated (sham). Forty-eight hours after the operation, the rats were subjected to a series of assessments. We found that prior exposure to EE improved functional outcomes, reduced infarct volume and attenuated histological damage. The apoptotic cell numbers in the ischemic penumbra cortex decreased in PIEE group, as did the p53, PUMA, Bax and AIF expression levels. The protein expression of Bcl-2 and HSP70 was increased in the PIEE group compared with the PISC group. PIEE treatment also significantly increased the BDNF level in the ischemic penumbra. In addition, inhibition of cell apoptosis and upregulation of BDNF expression levels were correlated with the improved functional recovery of MCAO rats.

CONCLUSIONS

These findings suggest that EE preconditioning inhibited cell apoptosis and upregulated BDNF expression in the penumbra of MCAO rats, which may contribute to neurofunctional recovery after stroke.

Correlation Analysis Between Local Cerebral Blood Flow and Severity of Vascular Cognitive Dysfunction

Research methods: This paper analyses the correlation between cerebral blood flow perfusion caused by cerebral vascular stenosis and the reduction of patients with cognitive dysfunction and white matter damage. A total of 118 patients with reduced cerebral blood flow perfusion due to cerebrovascular stenosis were selected to be included in the disease group, and 118 patients with no cerebrovascular stenosis and no neurological disease were included in the control group. The cerebral blood flow perfusion index and cognitive function index were compared between the two groups of patients. The correlation between each index and the degree of brain white matter damage was analysed. Results: The scores of brain white matter damage in patients with disease group were higher than those in control group, and cCBV, cCBF, TTP, MTT, MoCA, MMSE, ADL, and WMS were lower than those in control group, and the difference was statistically significant (P < 0.05). cCBV, cCBF, TTP, MTT, and white matter damage scores were highly correlated with MoCA, MMSE, ADL, and WMS (P < 0.05). There is a clear correlation between cerebral vascular perfusion, cognitive dysfunction, and white matter damage in patients with cerebrovascular stenosis. The more severe the perfusion of cerebral blood flow, the more severe the cognitive dysfunction and the white matter damage.

Human Brain-Derived Neurotrophic Factor Gene-Modified Bone Marrow Mesenchymal Stem Cells Combined With Erythropoietin Can Improve Acute Spinal Cord Injury

Objective:

To assess the effect as well as mechanism of bone marrow mesenchymal stem cells (BMSCs) modified by the human brain–derived neurotrophic factor gene combined with erythropoietin (EPO) in the treatment of acute spinal cord injury (SCI) in rats.

Methods:

The Brain-derived neurotrophic factor (BDNF) gene was transected by a virus vector. Rats with SCI were randomly split into following groups: The normal saline (NS) group, the EPO group, The Basso, Beattie, and Bresnahan scores, messenger RNA BDNF expression, and apoptosis rates were compared between the 4 groups at 1, 3, 7, 14, and 21 days after SCI.

Results:

At 7, 14, and 21 days after operation, the expression of the BDNF gene in the other 3 groups was higher than that of the NS group, and the difference was statistically significant (P < .05). The apoptosis rate in the combined group was less than that of NS, EPO, and BDNF/BMSC groups, and the differences were statistically significant (P < .05).

Conclusion:

Brain-derived neurotrophic factor gene-modified BMSC transplantation combined with EPO can promote the repair of nerve function after SCI in rats.

Effect of crocin on morphine tolerance and serum BDNF levels in a rat model of neuropathic pain

BACKGROUND

Chronic use of morphine treatment for neuropathic pain leads to morphine-induced analgesic tolerance. Crocin contained in Crocus sativus L., exerts anti-inflammatory and analgesic effects. This study examined the effects of crocin on morphine tolerance and serum BDNF levels on neuropathic pain induced by chronic constriction injury (CCI) in rats.

METHODS

CCI model of neuropathic pain was done in male Wistar rats (200-250 g). Rats were treated with crocin (15 or 30 mg/kg, intraperitoneally) alone or simultaneously with morphine (10 mg/kg, subcutaneously) during or after induction of CCI. Pain behavioral responses including mechanical allodynia and thermal hyperalgesia were measured from days of 15-27 after CCI. Then, rats were evaluated for serum BDNF levels on days 14 and/or 27.

RESULTS

We found that morphine tolerance developed after the induction of neuropathic pain. The injection of crocin (15 and 30 mg/kg) was able to enhance analgesic effect of morphine by reduction of mechanical allodynia on days 15-27 post-surgery in CCI rats. While preemptive administration of crocin at a lower dose (15 mg/kg) maintained the analgesic effect of morphine. Morphine injection and/or co-administration with crocin (15, 30 mg/kg) decreased serum BDNF levels in CCI rats.

CONCLUSION

These findings indicate that crocin may have a therapeutic effect to maintain morphine analgesic efficacy and also to prevent the development of morphine tolerance in neuropathic pain, but probably not through BDNF.

Protein Network Analysis of the Serum and Their Functional Implication in Patients Subjected to Traumatic Brain Injury

Traumatic brain injury (TBI) often leads to severe neurobehavioral impairment, but the underlying molecular mechanism remains to be elucidated. Here, we collected the sera from 23 patients (aged from 19 to 81 years old, third day after TBI as TBI-third group) subjected to TBI from The First Hospital of Kunming City, and the sera from 22 healthy donors (aged from 18 to 81 years old and as control group). Then, three samples from TBI-third group and three samples from control group were subjected to the protein microarray detection, and bioinformatics analysis. Then, enzyme-linked immunosorbent assay (ELISA) was used to verify significantly altered protein levels. Results showed that, when compared with the control group, all significantly differentially expressed proteins [DEPs, P < 0.05, FDR < 0.05, fold change (FC) > 2] contained 172 molecules in the TBI-third group, in which 65 proteins were upregulated, while 107 proteins were downregulated. The biological processes of these DEPs, mostly happened in the extracellular region and the extracellular region parts, are mainly involved in the regulation of cellular process, signaling and signal transduction, cell communication, response to stimuli, the immune system process and multicellular organismal development. Moreover, the essential molecular functions of them are cytokine activity, growth factor activity and morphogen activity. Additionally, the most significant pathways are enriched in cytokine–cytokine receptor interaction and PI3K-Akt signaling pathways among downregulated proteins, and pathways in cancer and cytokine–cytokine receptor interaction among upregulated proteins. Of these, we focused on the NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 with a high number of interactors in Protein–Protein Interaction (PPI) Network indicated by bioinformatics report. Furthermore, using ELISA test, we confirmed that all increase in the levels of NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 in the serum from TBI patients. Together, we determined the screened protein expressional profiles in serum for TBI patients, in which the cross-network between inflammatory factors and growth factors may play a crucial role in TBI damage and repair. Our findings could contribute to indication for the diagnosis and treatment of TBI in future translational medicine and clinical practice.

Improved Healing after the Co-Transplantation of HO-1 and BDNF Overexpressed Mesenchymal Stem Cells in the Subacute Spinal Cord Injury of Dogs

Abundant expression of proinflammatory cytokines after a spinal cord injury (SCI) creates an inhibitory microenvironment for neuroregeneration. The mesenchymal stem cells help to mitigate the inflammation and improve neural growth and survival. For this purpose, we potentiated the function of adipose-derived mesenchymal stem cells (Ad-MSCs) by transfecting them with brain-derived neurotrophic factor (BDNF) and heme oxygenase-1 (HO-1), through a lentivirus, to produce BDNF overexpressed Ad-MSCs (BDNF-MSCs), and HO-1 overexpressed Ad-MSCs (HO-1-MSCs). Sixteen SCI beagle dogs were randomly assigned into four treatment groups. We injected both HO-1 and BDNF-overexpressed MSCs as a combination group, to selectively control inflammation and induce neuroregeneration in SCI dogs, and compared this with BDNF-MSCs, HO-1-MSCs, and GFP-MSCs injected dogs. The groups were compared in terms of improvement in canine Basso, Beattie, and Bresnahan (cBBB) score during 8 weeks of experimentation. After 8 weeks, spinal cords were harvested and subjected to western blot analysis, immunofluorescent staining, and hematoxylin and eosin (H&E) staining. The combination group showed a significant improvement in hindlimb functions, with a higher BBB score, and a robust increase in neuroregeneration, depicted by a higher expression of Tuj-1, NF-M, and GAP-43 due to a decreased expression of the inflammatory markers interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and an increased expression of interleukin-10 (IL-10) (P ≤ 0.05). H&E staining showed more reduced intraparenchymal fibrosis in the combination group than in other groups (P ≤ 0.05). It was thus suggested that the cotransplantation of HO-1 and BDNF-MSCs is more effective in promoting the healing of SCI. HO-1-MSCs reduce inflammation, which favors BDNF-induced neuroregeneration in SCI of dogs.

Methylene blue protects dopaminergic neurons against MPTP-induced neurotoxicity by upregulating brain-derived neurotrophic factor

The relatively old, yet clinically used, drug methylene blue (MB) is known to possess neuroprotective properties by reducing aggregated proteins, augmenting the antioxidant response, and enhancing mitochondrial function and survival in various models of neurodegenerative diseases. In this study, we aimed to examine the effects of MB in Parkinson's disease (PD) in vivo and in vitro models by using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP⁺ ) with a focus on possible effects on induction of neurotrophic factors. Our results indicate that pretreatment with MB significantly attenuated MPTP-induced loss of dopaminergic neurons, glial cell activation, and depletion of dopamine. We also found that MB upregulated brain-derived neurotrophic factor (BDNF) and activated its downstream signaling pathways, suggesting that BDNF might be a contributor to MB-associated neuroprotection. Specific inhibition of the BDNF receptor or extracellular signal-regulated kinase (Erk) reversed the MB-mediated protection against MPP⁺ toxicity, thus implying a role for BDNF and the Erk pathway in the neuroprotective effects. Taken together, our data suggest that MB protects neurons from MPTP neurotoxicity via induction of BDNF. Further study to determine whether MB preserves dopaminergic neurons in the brains of PD patients is warranted.