OBJECTIVE: To investigate the effect of Zuogui Jiangtang Jieyu Decoction (ZJJ) on Shh signaling and self-renewal of neural stem cells in the hippocampal dentate gyrus of diabetic rats with depression. METHODS: Diabetic rat models with depression were randomly divided into model group, positive drug (metformin + fluoxetine) group, and low-, medium-, and high-dose ZJJ groups (n=16), with normal SD rats as the control group. The positive drugs and ZJJ were administered by gavage, and the rats in the control and model groups were given distilled water. After the treatment, blood glucose level was detected using test strips, and behavioral changes of the rats were assessed by forced swimming test and water maze test. ELISA was used to examine the serum level of leptin; The expressions of nestin and Brdu proteins in the dentate gyrus of the rats were detected using immunofluorescence assay, and the expressions of self-renewal marker proteins and Shh signaling proteins were detected using Western blotting. RESULTS: The diabetic rats with depression showed significantly increased levels of blood glucose and leptin (P < 0.01) and prolonged immobility time in forced swimming test (P < 0.01) and increased stage climbing time with reduced stage seeking time and stage crossings in water maze test (P < 0.01). The expressions of nestin and Brdu in the dentate gyrus, the expressions of cyclin D1, SOX2, Shh, Ptch1, Smo in the hippocampus and the nuclear expression of Gli-1 were decreased (P < 0.01) while hippocampal Gli-3 expression was increased significantly (P < 0.01) in the rat models. Treatment of rat models with high-dose ZJJ significantly reduced the blood glucose (P < 0.01) and leptin level (P < 0.05) and improved their performance in behavioral tests (P < 0.01). The treatment also obviously increased the expressions of nestin, Brdu, cyclin D1, SOX2, Shh, Ptch1, and Smo and the nuclear expression of Gli-1 in the dentate gyrus (P < 0.01) and reduced hippocampal expression of Gli-3 (P < 0.05) in the rat models. CONCLUSION ZJJ can significantly improve the self-renewal ability of neural stem cells and activate Shh signaling in dentate gyrus of diabetic rats with depression.
Animals ; Rats ; Blood Glucose ; Bromodeoxyuridine ; Cell Self Renewal ; Cyclin D1 ; Dentate Gyrus ; Depression ; Diabetes Mellitus, Experimental ; Hippocampus ; Leptin ; Nestin ; Rats, Sprague-Dawley

Humans ; Epilepsy, Temporal Lobe/surgery* ; Mossy Fibers, Hippocampal ; Brain-Derived Neurotrophic Factor ; Dentate Gyrus

Animals ; Dentate Gyrus ; Hippocampus ; Rats ; Receptors, Adrenergic, beta ; Sleep ; Spatial Learning

BACKGROUND: Anterior thalamic nuclei (ATN) deep brain stimulation (DBS) is an effective method of controlling epilepsy, especially temporal lobe epilepsy. Mossy fiber sprouting (MFS) plays an indispensable role in the pathogenesis and progression of epilepsy, but the effect of ATN-DBS on MFS in the chronic stage of epilepsy and the potential underlying mechanisms are unknown. This study aimed to investigate the effect of ATN-DBS on MFS, as well as potential signaling pathways by a kainic acid (KA)-induced epileptic model. METHODS: Twenty-four rhesus monkeys were randomly assigned to control, epilepsy (EP), EP-sham-DBS, and EP-DBS groups. KA was injected to establish the chronic epileptic model. The left ATN was implanted with a DBS lead and stimulated for 8 weeks. Enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining were used to evaluate MFS and levels of potential molecular mediators in the hippocampus. One-way analysis of variance, followed by the Tukey post hoc correction, was used to analyze the statistical significance of differences among multiple groups. RESULTS: ATN-DBS is found to significantly reduce seizure frequency in the chronic stage of epilepsy. The number of ectopic granule cells was reduced in monkeys that received ATN stimulation (P < 0.0001). Levels of 3',5'-cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) in the hippocampus, together with Akt phosphorylation, were noticeably reduced in monkeys that received ATN stimulation (P = 0.0030 and P = 0.0001, respectively). ATN-DBS also significantly reduced MFS scores in the hippocampal dentate gyrus and CA3 sub-regions (all P < 0.0001). CONCLUSION ATN-DBS is shown to down-regulate the cAMP/PKA signaling pathway and Akt phosphorylation and to reduce the number of ectopic granule cells, which may be associated with the reduced MFS in chronic epilepsy. The study provides further insights into the mechanism by which ATN-DBS reduces epileptic seizures.
Adenosine Monophosphate ; Anterior Thalamic Nuclei ; Cyclic AMP-Dependent Protein Kinases ; Deep Brain Stimulation ; Epilepsy/therapy* ; Epilepsy, Temporal Lobe/therapy* ; Hippocampus ; Humans ; Mossy Fibers, Hippocampal ; Signal Transduction

The objective of this study was to elucidate the effect of chronic stress (CS) on dopamine (DA) level and synaptic efficiency in the hippocampal dentate gyrus (DG) during spatial learning and memory. Sprague Dawley (SD) male rats were randomly divided into control group and CS group (n = 10). CS group was treated with chronic mild unpredictable stress, and control group did not receive any treatments. The levels of epinephrine and corticosterone (CORT) in serum were measured by using enzyme-linked immunosorbent assay (ELISA); the spatial learning and memory abilities of rats were measured by Morris water maze (MWM) test. Meanwhile, the amplitude of field excitatory postsynaptic potential (fEPSP) and concentration of DA in the DG region were determined by in vivo electrophysiology, microdialysis and HPLC techniques during MWM test in rats. After that, the DA D1 receptor (D1R) and its key downstream members in DG were examined by immunohistochemistry or Western blot assay. The results showed that the levels of epinephrine and CORT in the serum of the rats in CS group were significantly increased compared with those in the control group (P < 0.05). In CS group rats, the escape latency was significantly prolonged and the number of platform crossing was markedly decreased during MWM test, compared with those in control group (P < 0.05). Furthermore, the amplitude of fEPSP in the DG was not changed during MWM test in CS rats, while it was significantly increased on the 3rd day of MWM test in control group (P < 0.05). Compared with baseline or control group, CS group showed significantly increased DA level from the 1st to 3rd days of MWM test in the DG (P < 0.05). In addition, the protein expression of D1R was markedly up-regulated in the DG in CS group, while the protein expression levels of p-PKA, p-CREB and BDNF were significantly reduced, compared with those in control group. These results suggest that CS may impair spatial learning and memory abilities in rats through the enhancement of the DA levels in the hippocampal DG.
Animals ; Dentate Gyrus ; Dopamine ; Hippocampus ; Male ; Maze Learning ; Rats ; Rats, Sprague-Dawley ; Spatial Learning ; Spatial Memory

OBJECTIVE: To observe the effects of acupuncture at "Baihui" (GV 20) and "Shenshu" (BL 23) on the ultrastructure of hippocampal dentate gyrus in rats with Alzheimer's disease. METHODS: Forty SPF Wistar male rats were randomly divided into a normal group, a sham operation group, a model group and an acupuncture group, 10 rats in each one. The rats in the model group and the acupuncture group were treated with injection of 5 μL Aβ at bilateral hippocampus, while the rats in the sham operation group were treated with injection of 5 μL 0.9% NaCl. Three days after modeling, the rats in the acupuncture group were treated with acupuncture at "Baihui" (GV 20) and "Shenshu" (BL 23) for 20 min, once a day, six treatments constituted a course, and totally two courses were given with an interval of 1 day between courses. The rats in the other groups received normal diet and no treatment was given. Before modeling, four days after modeling and after treatment, water maze test was performed to observe the escape latency and the number of crossing platforms. The hippocampal dentate gyrus was collected and transmission electron microscope was applied to observe the ultrastructure changes of neurons and astrocytes. RESULTS: ①Four days after modeling, compared with the normal group and the sham operation group, the escape latency was significantly prolonged and the number of crossing platforms was reduced in the model group (all <0.01); after treatment, compared with the model group, the escape latency was significantly reduced and the number of crossing platforms was increased in the acupuncture group (both <0.01). ②In the normal group and the sham operation group, the morphology of neurons and astrocytes was intact, the nuclear and membrane structure were clear, and the morphology of organelles such as mitochondria, endoplasmic reticulum and lysosomes was normal. In the model group, the morphology of neurons was irregular, the nucleus was severely constricted with edema in the cytoplasm, the color of heterochromatin was deepened, the endoplasmic reticulum was expanded, the granulation was removed and the number of mitochondria was decreased, even with malformed-like change in mitochondrial cristae; there was severe edema around astrocytes, few organelles in the cytoplasm, severe swelling of mitochondria and mild expansion of the endoplasmic reticulum. In the acupuncture group, the edema of the neuron and astrocytes was still evident, and the mitochondrial was mildly swollen but relieved compared with that in the model group, and there were no obvious abnormalities in neuronal endoplasmic reticulum and ribosomes. CONCLUSION Acupuncture could improve the ultrastructure of neurons and astrocytes in the hippocampal dentate gyrus in rats with Alzheimer's disease induced by Aβ.
Acupuncture Therapy ; Alzheimer Disease ; Amyloid beta-Peptides ; Animals ; Astrocytes ; Dentate Gyrus ; Hippocampus ; Male ; Neurons ; Peptide Fragments ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar

OBJECTIVE: Although, accumulating evidence is delineating a neuroprotective and neurotrophic role for lithium (Li), inconsistent findings have also been reported in human studies especially. Moreover, the effects of Li infusion into the hippocampus are still unknown. The aims of this work were (a) to assess whether basal synaptic activity and long-term potentiation (LTP) in the hippocampus are different in regard to intrahippocampal Li infusion; (b) to assess spatial learning and memory in rats chronically treated with LiCO₃ in the Morris water maze. METHODS: Field potentials were recorded form the dentate gyrus, stimulating perforant pathways, in rats chronically (20 mg/kg for 40 days) or acutely treated with LiCO₃ and their corresponding control rats. In addition, performance of rats in a Morris water maze was measured to link behaviour of rats to electrophysiological findings. RESULTS: LiCO₃ infusion into the hippocampus resulted in enhanced LTP, especially in the late phases, but attenuated LTP was observed in rats chronically treated with Li as compared to controls. Li-treated rats equally performed a spatial learning task, but did spend less time in target quadrant than saline-treated rats in Morris water maze. CONCLUSION: Despite most data suggest that Li always yields neuroprotective effects against neuropathological conditions; we concluded that a 40-day treatment of Li disrupts hippocampal synaptic plasticity underlying memory processes, and that these effects of prolonged treatment are not associated with its direct chemical effect, but are likely to be associated with the molecular actions of Li at genetic levels, because its short-term effect preserves synaptic plasticity.
Adult ; Animals ; Dentate Gyrus ; Hippocampus ; Humans ; Learning ; Lithium ; Long-Term Potentiation ; Memory ; Neuronal Plasticity ; Neuroprotective Agents ; Perforant Pathway ; Rats ; Spatial Learning ; Spatial Memory ; Water

Silent information regulator 2 (Sirtuin2 / SIRT2) is a NAD⁺-dependent deacetylase that regulates the cellular oxidative stress response. It modulates transcriptional silencing and protein stability through deacetylation of target proteins including histones. Previous studies have shown that SIRT2 plays a role in mood disorders and hippocampus-dependent cognitive function, but the underlying neurobiological mechanism is poorly understood. Here, we report that chronic stress suppresses SIRT2 expression in the hippocampus. Molecular and biochemical analyses indicate that the stress-induced decrease in the SIRT2 expression downregulates synaptic plasticity-related genes in the hippocampus through the increase of euchromatic histone-lysine N-methyltransferase 2 (Ehmt2) (also known as G9a). shRNA-mediated knockdown of SIRT2 in the dentate gyrus alters the expression of synaptic plasticity-related genes in a way similar to those induced by chronic stress, and produces depression-like behaviors. Our results indicate that SIRT2 plays an important role in the response to stress, thereby modulating depression-like behaviors.
Cognition ; Dentate Gyrus ; Depression ; Down-Regulation ; Hippocampus ; Histone-Lysine N-Methyltransferase ; Histones ; Mood Disorders ; Neuronal Plasticity ; Oxidative Stress ; Protein Stability ; Up-Regulation

MicroRNA-132 (miR-132), a small RNA that regulates gene expression, is known to promote neurogenesis in the embryonic nervous system and adult brain. Although exposure to psychoactive substances can increase miR-132 expression in cultured neural stem cells (NSCs) and the adult brain of rodents, little is known about its role in opioid addiction. So, we set out to determine the effect of miR-132 on differentiation of the NSCs and whether this effect is involved in opioid addiction using the rat morphine self-administration (MSA) model. We found that miR-132 overexpression enhanced the differentiation of NSCs in vivo and in vitro. Similarly, specific overexpression of miR-132 in NSCs of the adult hippocampal dentate gyrus (DG) during the acquisition stage of MSA potentiated morphine-seeking behavior. These findings indicate that miR-132 is involved in opioid addiction, probably by promoting the differentiation of NSCs in the adult DG.
Animals ; Cell Differentiation ; Cell Line, Tumor ; Dentate Gyrus ; metabolism ; Gene Expression Regulation ; Male ; MicroRNAs ; metabolism ; Neural Stem Cells ; metabolism ; Opioid-Related Disorders ; metabolism ; Rats, Sprague-Dawley

In the present study, we investigated the effects of heat shock protein 70 (HSP70) on novel object recognition, cell proliferation, and neuroblast differentiation in the hippocampus. To facilitate penetration into the blood–brain barrier and neuronal plasma membrane, we created a Tat-HSP70 fusion protein. Eight-week-old mice received intraperitoneal injections of vehicle (10% glycerol), control-HSP70, or Tat-HSP70 protein once a day for 21 days. To elucidate the delivery efficiency of HSP70 into the hippocampus, western blot analysis for polyhistidine was conducted. Polyhistidine protein levels were significantly increased in control-HSP70- and Tat-HSP70-treated groups compared to the control or vehicle-treated group. However, polyhistidine protein levels were significantly higher in the Tat-HSP70-treated group compared to that in the control-HSP70-treated group. In addition, immunohistochemical study for HSP70 showed direct evidences for induction of HSP70 immunoreactivity in the control-HSP70- and Tat-HSP70-treated groups. Administration of Tat-HSP70 increased the novel object recognition memory compared to untreated mice or mice treated with the vehicle. In addition, the administration of Tat-HSP70 significantly increased the populations of proliferating cells and differentiated neuroblasts in the dentate gyrus compared to those in the control or vehicle-treated group based on the Ki67 and doublecortin (DCX) immunostaining. Furthermore, the phosphorylation of cAMP response element-binding protein (pCREB) was significantly enhanced in the dentate gyrus of the Tat-HSP70-treated group compared to that in the control or vehicle-treated group. Western blot study also demonstrated the increases of DCX and pCREB protein levels in the Tat-HSP70-treated group compared to that in the control or vehicle-treated group. In contrast, administration of control-HSP70 moderately increased the novel object recognition memory, cell proliferation, and neuroblast differentiation in the dentate gyrus compared to that in the control or vehicle-treated group. These results suggest that Tat-HSP70 promoted hippocampal functions by increasing the pCREB in the hippocampus.
Animals ; Blotting, Western ; Cell Membrane ; Cell Proliferation ; Cyclic AMP Response Element-Binding Protein ; Dentate Gyrus ; Heat-Shock Proteins ; Hippocampus ; Hot Temperature ; HSP70 Heat-Shock Proteins ; Injections, Intraperitoneal ; Memory ; Mice ; Neurons ; Phosphorylation