Ferritin reduction is essential for cerebral ischemia-induced hippocampal neuronal death through p53/SLC7A11-mediated ferroptosis.

Cerebral ischemia is the most common cause of hippocampal neuronal death and the most prevalent cause of stroke with high mortality rate. Ferroptosis has been suggested to affect the role of hippocampal neurons. This study explores the influence of lentivirus infection-induced ferritin overexpression in hippocampal neuronal injury and death through simulations in August Copenhagen Irish rat models. Twenty-four-hour cerebral ischemia-reperfusion injury was induced in the rats after 90-min middle cerebral artery occlusion (MCAO). Ferritin overexpression was induced through lentivirus infection. The Morris Water Maze (MWM) test and tau hyperphosphorylation test were performed on hippocampal neurons to establish a MCAO model. The effect of ferritin overexpression on hippocampal neuronal death was evaluated using hematoxylin-eosin staining and annexin V/propidium iodide flow cytometry. The MWM test revealed that MCAO modeling decreased the cognitive and locomotor capacity of the rats, whereas ferritin overexpression partially reversed the effect of MCAO. In addition, the hyperphosphorylation of tau caused by MCAO was reduced by ferritin. Pathogenic changes, impaired viability, increased apoptosis, and elevated caspase-9 cleavage in hippocampal neurons were clearly recovered by ferritin. Moreover, robust reactive oxygen species production and glutathione consumption, which was induced by MCAO modeling, were ameliorated by ferritin. Furthermore, two key modulators of ferroptosis, p53 and SLC7A11, were demonstrated to be upregulated by MCAO modeling and downregulated by ferritin. Ferritin reduction is essential for cerebral ischemia-induced hippocampal neuronal ferroptosis mediated via p53 and SLC7A11.

MicroRNA-107 Ameliorates Damage in a Cell Model of Alzheimer's Disease by Mediating the FGF7/FGFR2/PI3K/Akt Pathway.

Alzheimer's disease (AD), the most prevalent representation of dementia, is a neurodegenerative disease resulting from the degenerative disturbance of the central nervous system. Previous studies have indicated that miR-107 is reduced in the brain neocortex of patients with AD; however, its underlying mechanism is not clear. Therefore, the objective of this study was to explore the question of whether miR-107 participates in AD development. The study confirmed that the miR-107 expression levels were dramatically decreased in patients with AD and in beta-amyloid (Aß) (Aß)-treated SH-SY5Y cells compared with control groups. Upregulation of miR-107 reversed the inhibitory role of Aß on cell proliferation and viability. In addition, miR-107 upregulation also ameliorated the Aß-induced inflammation and apoptosis of SH-SY5Y cells. Furthermore, using bioinformatic prediction, dual-luciferase reporter assay (DLRA), quantitative polymerase chain reaction (qPCR), and Western blot (WB), miR-107 was confirmed to reduce the expression level of FGF7, and it subsequently deactivated the FGFR2/PI3K/Akt pathway. Moreover, FGF7 overexpression counteracted the role of miR-107 in the viability, proliferation, inflammation, and apoptosis of Aß-induced SH-SY5Y cells.

Comorbidity of Pain and Depression in a Lumbar Disc Herniation Model: Biochemical Alterations and the Effects of Fluoxetine.

of Background Data: Depression is one of the most common comorbidities in patients with chronic low back pain. However, the mechanisms of depression in chronic low back pain patients and the effect of antidepressants on the comorbidity of pain and depression need to be further explored. The establishment of the appropriate animal models and of more effective therapies is critical for this comorbidity. Lumbar disc herniation (LDH) is the most common disease that causes low back pain. The current study examined whether an LDH model shows behavioral and biochemical alterations that are in accordance with the characteristics of the comorbidity of pain and depression and tested the effect of fluoxetine (FLX) on these measures. Objective: The current study examined whether an LDH model showed the behavioral and biochemical alterations that were in accordance with the characteristics of the comorbidity of pain and depression and tested the effect of FLX on these measures. Methods: The LDH animal model was generated by the implantation of the autologous nucleus pulposus on the left L5 nerve root just proximal to the dorsal root ganglion in Wistar rats. Pain intensity was evaluated by mechanical allodynia and thermal hyperalgesia, and changes in depressive behavior were examined by the taste preference and forced swim tests. Hippocampal serotonin (5-HT) levels were measured by liquid chromatography-mass spectrometry, and tumor necrosis factor-α (TNF-α) mRNA was quantified using real-time reverse transcriptase PCR. Results: LDH resulted in chronic pain, which further induced depressive behavior that persisted for 6 weeks after surgery. There were decreased 5-HT concentrations and upregulated TNF-α mRNA levels that were accompanied by behavioral changes. FLX treatment improved depressive behavior and moderately alleviated pain through increased 5-HT concentrations, and inhibited TNF-α mRNA expression. Conclusions: In summary, our studies provide initial evidence that the LDH chronic pain model might serve as a model of the comorbidity of low back pain and depression. The finding that FLX improved depressive behavior and pain through normalized 5-HT concentrations and TNF-α mRNA expression establishes the initial mechanism of the comorbidity of pain and depression.

Hypoxic preconditioning improves the survival and neural effects of transplanted mesenchymal stem cells via CXCL12/CXCR4 signalling in a rat model of cerebral infarction.

The treatment of neural deficiency after cerebral infarction is challenging, with limited therapeutic options. The transplantation of mesenchymal stem cells (MSCs) to the ischemic penumbra is a potential therapeutic approach. In the present study, a cerebral infarction model was generated by performing middle cerebral artery occlusion (MCAO) in SD rats. The expression of CXCR4 increased, and the number of MSCs migrating to the peri-infarct area was higher in rats transplanted with preconditioned MSCs than in rats transplanted with untreated MSCs. The rate of apoptosis, as evaluated by TUNEL staining and immunoblotting assays, was reduced in rats receiving preconditioned MSCs. A significant amelioration of neural regeneration and improved neurological function were observed in rats injected with preconditioned MSCs compared with those injected with untreated MSCs. However, the application of an siRNA targeting CXCL12 significantly inhibited the protective role of preconditioned MSCs against apoptosis and promoted the migration of MSCs to the ischemic area, leading to impaired neuronal regeneration and limited recovery of neuronal function. Hypoxic preconditioning of MSCs prior to transplantation suppressed apoptosis and increased their migration abilities, leading to the promotion of neuronal regeneration and improvement in neural function after transplantation. This preconditioning strategy may be considered as a potential approach for the modification of MSCs prior to cell transplantation therapy in patients with cerebral infarction. SIGNIFICANCE OF THE STUDY: We found that hypoxic preconditioning of MSCs improved their ability to promote neuronal regeneration and the recovery of neuronal function. Moreover, we showed that CXCR4 inhibited apoptosis, improved cell homing, and promoted neuronal differentiation, without influencing angiogenesis. Our study provides a relatively safe preconditioning method for potential use for cell transplantation therapy in ischemic cerebral infarction. The results presented here will facilitate the development of novel strategies and techniques to improve the tolerance and migration ability of transplanted cells for the treatment of cerebral infarction sequelae.

Differences in Tribological Behaviors upon Switching Fixed and Moving Materials of Tribo-pairs including Metal and Polymer.

The coefficient of friction (COF) between two materials is usually believed to be an intrinsic property of the materials themselves. In this study, metals of stainless steel (304) and brass (H62), and polymers of polypropylene (PP) and polytetrafluoroethylene (PTFE) were tested on a standard ball-on-three-plates test machine. Significantly different tribological behaviors were observed when fixed and moving materials of tribo-pairs (metal/polymer) were switched. As an example, under the same applied load and rotating speed, the COF (0.49) between a rotating PP ball and three fixed H62 plates was approximately 2.3 times higher than that between switched materials of tribo-pairs. Meanwhile, the COF between H62 and PTFE was relatively stable. The unexpected tribological behaviors were ascribed to the thermal and mechanical properties of tribo-pairs. Theoretical analysis revealed that the differences in the maximum local temperature between switching the fixed and moving materials of tribo-pairs were consistent with the differences in the tested COF. This result indicated the precise prediction of the COF of two materials is complexcity, and that thermal and mechanical properties should be properly considered in designing tribo-pairs, because these properties may significantly affect tribological performance.

Mechanism of action of Zhuyu Annao pill in mice with cerebral intrahemorrhage based on TLR4.

OBJECTIVE: To explore the protective effect and possible mechanism of action of Zhuyu Annao pill in mice with intracerebral hemorrhage (ICH). METHODS: Sixty mice were divided into the control group, hemorrhage group, drug-treated group (after hemorrhage), TLR4-knockout hemorrhage group and TLR4-knockout hemorrhage + drug-treated group (after hemorrhage) with 12 in each group. Model of autologous ICH was established in all groups. After drilling and 12 h of fasting, models in the control group hemorrhage group and TLR4-knockout hemorrhage group were all drenched with 10 mL/kg distilled water by intragastric administration. Models in the drug-treated group and TLR4-knockout hemorrhage + drug-treated group were drenched with 6.25 g/kg of Zhuyu Annao pill. All groups were treated for 7 d. Longa scoring method was used to measure the neurological defect scores and determine the brain water contents of all groups; ELISA was employed to detect the inflammatory factor interleukin (IL)-6, tumor necrosis factor-α (TNF-α) and IL-1ß in brain tissues; and Western blot was applied to test the expression quantities of apoptotic protein Bax and anti-apoptotic protein Bcl-2 in brain tissues. RESULTS: At day 3 and 7, compared with the hemorrhage group, the neurological defect scores of the drug-treated group, TLR4-knockout hemorrhage group and TLR4-knockout hemorrhage + drug-treated group decreased significantly (P < 0.05). Compared with the hemorrhage group, the brain water contents of the drug-treated group, TLR4-knockout hemorrhage group and TLR4-knockout hemorrhage + drug-treated group reduced significantly (P < 0.05). Compared with the hemorrhage group, the inflammatory factor IL-6, TNF-α and IL-1ß of the drug-treated group, TLR4-knockout hemorrhage group and TLR4-knockout hemorrhage + drug-treated group decreased significantly (P < 0.05). Compared with the hemorrhage group, the expression of apoptotic protein Bax of the drug-treated group, TLR4-knockout hemorrhage group and TLR4-knockout hemorrhage + drug-treated group decreased significantly and the expression of anti-apoptotic protein Bcl-2 increased significantly (P < 0.05). CONCLUSIONS: Zhuyu Annao pill can alleviate encephaledema for mice with ICH and reduce inflammatory responses and nerve cell apoptosis. TLR4 can mediate inflammatory injury induced by ICH. Thus, Zhuyu Annao pill can play a protective role for brains by decreasing the expression of TLR4.