To investigate the dynamic changes in hippocampal metabolism after microwave radiation using liquid chromatography in tandem with mass spectrometry/mass spectrometry (LC-MS/MS) and to identify potential biomarkers. Wistar rats were randomly assigned to a sham group and a microwave radiation group. The rats in the microwave radiation group were exposed to 2.856 GHz for 15 min for three times, with 5 min intervals. The rats in the sham group were not exposed. Transmission electron microscope revealed blurring of the synaptic cleft and postsynaptic dense thickening in hippocampal neurons after microwave radiation. Metabolomic analysis revealed 38, 24, and 39 differentially abundant metabolites at 3, 7, and 14 days after radiation, respectively, and the abundance of 9 metabolites, such as argininosuccinic acid, was continuously decreased. After microwave radiation, the abundance of metabolites such as argininosuccinic acid was successively decreased, indicating that these metabolites could be potential biomarkers for hippocampal tissue injury.

(1) Background: Depression is one of the overwhelming public health problems. Alleviating hippocampus injury may prevent depression development. Herein, we established the chronic unpredictable mild stress (CUMS) model and aimed to investigate whether aerobic exercise (AE) could alleviate CUMS induced depression-like behaviors and hippocampus injury. (2) Methods: Forty-eight healthy male Sprague-Dawley rats (200 ± 20 g) were randomly divided into 4 groups (control, CUMS, CUMS + 7 days AE, CUMS + 14 days AE). Rats with AE treatments were subjected to 45 min treadmill per day. (3) Results: AE intervention significantly improved CUMS-induced depressive behaviors, e.g., running square numbers and immobility time assessed by the open field and forced swimming test, suppressed hippocampal neuron apoptosis, reduced levels of phosphorylation of NMDA receptor and homocysteine in hippocampus, as well as serum glucocorticoids, compared to the CUMS rats. In contrast, AE upregulated phosphorylation of AMPAR receptor and brain-derived neurotrophic factor (BDNF) hippocampus in CUMS depression rats. The 14 day-AE treatment exhibited better performance than 7 day-AE on the improvement of the hippocampal function. (4) Conclusion: AE might be an efficient strategy for prevention of CUMS-induced depression via ameliorating hippocampus functions. Underlying mechanisms may be related with glutamatergic system, the neurotoxic effects of homocysteine, and/or influences in glucocorticoids-BDNF expression interaction.

OBJECTIVE: The present study aimed to examine whether Am80 (tamibarotene) protects the hippocampus against cerebral ischemia-reperfusion (I/R) injury and whether phosphoinositide-3-kinase/Akt (PI3K/Akt) pathway mediates this effect.
METHODS: Rats were subjected to 90 minutes of middle cerebral artery occlusion followed by 24 hours of reperfusion. The animals were randomly divided into 7 groups: sham-operated group; I/R group; groups pretreated with 2 mg/kg, 6 mg/kg, and 10 mg/kg of Am80; Am80 (6 mg/kg) combined with the selective PI3K inhibitor wortmannin (0.6 mg/kg), and wortmannin (0.6 mg/kg) only group. After 24 hours of reperfusion, neurological deficits and infarct volume were measured. Pathological changes in hippocampal neurons were analyzed by transmission electron microscopy. Neuronal survival was examined by TUNEL staining. The expression of Bcl-2, Bax, and Akt, and Akt phosphorylation (p-Akt) were measured by Western blotting and quantitative real-time polymerase chain reaction.
RESULTS: The pretreatment with Am80 improved the neurologic deficit score, reduced infarct volume, and decreased the number of TUNEL-positive cells in the hippocampus. Moreover, Am80 pretreatment downregulated the expression of Bax, upregulated the expression of Bcl-2, and increased the level of p-Akt. Wortmannin abolished in part the increase in p-Act and the neuroprotective effect exerted on the ischemic by Am80 pretreatment.
CONCLUSIONS: Our results documented that Am80 pretreatment protects ischemic hippocampus after cerebral I/R by regulating the expression of apoptosis-related proteins through the activation of the PI3K/Akt signaling pathway.

Hepatic ischemia reperfusion (HIR) has been found to induce brain injury and cognitive dysfunction. Dynamin-related protein 1 (Drp1) mediated mitochondrial fission involves oxidative stress, apoptosis and several neurological diseases. In this study, we investigated whether Drp1 translocation to mitochondria was implicated in HIR induced hippocampus injury in young mice, and further detected the role of calcineurin in the regulation of mitochondrial dynamics. 2-week C57BL/6 mice were chosen to make HIR model. Western blot was used to detect mitochondrial dynamics regulating proteins in whole hippocampal tissues and extracted mitochondria. Transmission electron microscopy was used to observe mitochondrial morphology. TUNEL staining and ELISA (serum S100β/NSE concentrations) were used to evaluate neurons apoptosis and brain injury respectively. Drp1 inhibitor Mdivi-1 and calcineurin inhibitor FK506 were utilized to further confirm the role of Drp1 and calcineurin. Results showed that HIR affected mitochondrial dynamics in a fission-dominant manner with translocation of Drp1 to mitochondria in hippocampus of young mice. HIR induced increased expression of calcineurin and dephosphorylation of Drp1 at Ser637 in hippocampus. Treatment with Mdivi-1 and FK506 upregulated the phosphorylation of Drp1, inhibited Drp1 translocation to mitochondria, and alleviated mitochondrial fragmentation after HIR. What\'s more, Mdivi-1 and FK506 restrained cytochrome c release and cleaved caspase-3 expression, ameliorated hippocampal neurons apoptosis, and decreased serum S100β/NSE concentrations as well. These data suggest that calcineurin mediated Drp1 dephosphorylation and translocation to mitochondria play a crucial role in HIR induced mitochondrial fragmentation and neurons apoptosis in hippocampus.

Traumatic brain injury (TBI) is a major health concern in the United States resulting in a substantial number of hospitalizations and in a broad spectrum of symptoms and disabilities. In the clinical setting, neurological responsiveness and structural imaging are used to classify mild, moderate and severe TBI. To evaluate the complex secondary and severity-specific injury response, investigators have relied on pre-clinical rodent models. The controlled cortical impact (CCI) model in mice is a widely used to study TBI. The CCI method has demonstrated consistent intra-laboratory outcomes due to precise control of cortical depth penetration, dwell time and speed of impact. While the CCI method results in control of injury severity, there is no consensus regarding the injury parameters or behavioral and histological endpoints that constitute a mild, moderate or severe TBI in this model. This discrepancy has resulted in considerable variability across laboratories in the outcomes of CCI-induced mild, moderate, and severe TBI. Inconsistent with clinical evaluation, injury severity in the CCI model has predominately relied on the extent of tissue damage. In the present review, we discuss variations in surgical parameters for injury induction as well as the criteria used to determine injury severity. Additionally, we propose guiding principles for the induction and defining of mild, moderate and severe TBI in the craniectomy-dependent experimental mouse CCI model.