Electroacupuncture Pretreatment Ameliorates PTSD-Like Behaviors in Rats by Enhancing Hippocampal Neurogenesis via the Keap1/Nrf2 Antioxidant Signaling Pathway.

Electroacupuncture (EA) pretreatment is a clinically useful therapy for several brain disorders. However, whether and via which exact molecular mechanisms it ameliorates post-traumatic stress disorder (PTSD) remains unclear. In the present study, rats received EA stimulation for seven consecutive days before exposure to enhanced single prolonged stress (ESPS). Anxiety-like and fear learning behaviors; hippocampal neurogenesis; the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (keap1), and heme oxygenase 1 (HO-1); and the activity of AMP-activated kinase (AMPK) were evaluated at 14 days after ESPS. EA pretreatment improved hippocampal neurogenesis and ameliorated anxiety-like behaviors in ESPS-treated rats. EA pretreatment also increased the expression of Nrf2 and HO-1 and the activity of AMPK. Furthermore, Nrf2 knockdown by a short hairpin RNA affected anxiety-like behaviors and expression of neuroprotective markers (BDNF, DCX) in a manner similar to ESPS alone and dampened the neuroprotective effects of EA pretreatment. In contrast, Keap1 knockdown increased the expression of HO-1, improved hippocampal neurogenesis, and alleviated PTSD-like behaviors. Altogether, our results suggest that EA pretreatment ameliorates ESPS-induced anxiety-like behaviors and prevents hippocampal neurogenesis disruption in a rat model of PTSD possibly through regulation of the keap1/Nrf2 antioxidant defense pathway.

Early intervention with electroacupuncture prevents PTSD-like behaviors in rats through enhancing hippocampal endocannabinoid signaling.

Electroacupuncture (EA) is a clinically useful physiological therapy that has been recently adopted to treat several brain disorders. However, the potential role of early EA intervention in the prevention of posttraumatic stress disorder (PTSD) as well as its potential cellular and molecular mechanism has never been investigated previously. In the present study, we used an enhanced single prolonged stress (ESPS) model to access the effects of early EA intervention on the prevention of anxiety-like and fear learning behaviors, as well as the influence of the expression of post-synaptic density protein 95 (PSD95), synaptophysin (Syn), brain derived neurotrophic factor (BDNF), diacylglycerol lipase alpha (DAGLα) and cannabinoid type 1 receptor (CB1R) in the hippocampus with or without DAGLα or CB1R knockdown by a short hairpin RNA (shRNA) in the hippocampus. Moreover, the effects of electrical stimulation with different parameters on the expression of DAGLα and CB1R in the hippocampal astrocytes were also observed. The results showed that Early EA intervention improved hippocampal synaptic plasticity and ameliorated PTSD-like behaviors and also increased expression of BDNF, DAGLα and CB1R. However, either DAGLα or CB1R knockdown by a short hairpin RNA (shRNA) eliminated the neuroprotective effects of early EA intervention. Furthermore, electrical stimulation with 2/15 Hz 1 mA elevated the expression of DAGLα and CB1R. Altogether, our findings provide new insights regarding the possibility of using early EA intervention in the prevention of PTSD, and the protective effects of EA is involving the activation of DAGLα and CB1R.

Repetitive transcranial magnetic stimulation inhibits Sirt1/MAO-A signaling in the prefrontal cortex in a rat model of depression and cortex-derived astrocytes.

Repetitive transcranial magnetic stimulation (rTMS) is a useful monotherapy for depression or adjunctive therapy for resistant depression. However, the anti-depressive effects of different parameters and the underlying mechanisms remain unclear. Here, we aimed to assess the effect of rTMS with different parameters (1/5/10 Hz, 0.84/1.26 T) on the depressive-like behaviors, 5-hydroxytryptamine (5-HT), 5-HIAA (5-hydroxyindoleacetic acid) and DA and NE levels, and monoamine oxidase A (MAO-A) activity in chronic unpredictable stress-treated rats, along with the expression of sirtuin 1 (Sirt1) and MAO-A in the prefrontal cortex (PFC) and cortex-derived astrocytes from new-born rats. Moreover, the depressive-like behaviors were monitored following the transcranial injection of the Sirt1 inhibitor EX527 (1 mM) daily for 1 week. We found that rTMS treatment (5/10 Hz, 0.84/1.26 T) ameliorated depressive-like behaviors, increased 5-HT, DA and NE levels, decreased the 5-HIAA level and Sirt1 and MAO-A expression, and reduced MAO-A activity in the PFC. The depressive-like behaviors were also ameliorated after the transcranial injection of EX527. Importantly, rTMS (5/10 Hz, 0.84/1.26 T) inhibited Sirt1 and MAO-A expressions in astrocytes and Sirt1 knockdown with short hairpin RNA decreased MAO-A expression in astrocytes. These results suggest that the inhibition of Sirt1/MAO-A expression in astrocytes in the PFC may contribute to the different anti-depressive effects of rTMS with different parameters, and may also provide a novel insight into the mechanisms underlying major depressive disorder.

Neuroprotective effects of sevoflurane against electromagnetic pulse-induced brain injury through inhibition of neuronal oxidative stress and apoptosis.

Electromagnetic pulse (EMP) causes central nervous system damage and neurobehavioral disorders, and sevoflurane protects the brain from ischemic injury. We investigated the effects of sevoflurane on EMP-induced brain injury. Rats were exposed to EMP and immediately treated with sevoflurane. The protective effects of sevoflurane were assessed by Nissl staining, Fluoro-Jade C staining and electron microscopy. The neurobehavioral effects were assessed using the open-field test and the Morris water maze. Finally, primary cerebral cortical neurons were exposed to EMP and incubated with different concentration of sevoflurane. The cellular viability, lactate dehydrogenase (LDH) release, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were assayed. TUNEL staining was performed, and the expression of apoptotic markers was determined. The cerebral cortexes of EMP-exposed rats presented neuronal abnormalities. Sevoflurane alleviated these effects, as well as the learning and memory deficits caused by EMP exposure. In vitro, cell viability was reduced and LDH release was increased after EMP exposure; treatment with sevoflurane ameliorated these effects. Additionally, sevoflurane increased SOD activity, decreased MDA levels and alleviated neuronal apoptosis by regulating the expression of cleaved caspase-3, Bax and Bcl-2. These findings demonstrate that Sevoflurane conferred neuroprotective effects against EMP radiation-induced brain damage by inhibiting neuronal oxidative stress and apoptosis.

Limb remote ischemic preconditioning protects the spinal cord from ischemia-reperfusion injury: a newly identified nonneuronal but reactive oxygen species-dependent pathway.

BACKGROUND: It remains to be established whether spinal cord ischemic tolerance can be induced by limb remote ischemic preconditioning (RIPC), and the mechanisms underlying the neuroprotective effects of RIPC on the spinal cord need to be clarified. METHODS: Spinal cord ischemia was studied in New Zealand White rabbits. In experiment 1, all rabbits were subjected to 20-min spinal cord ischemia by aortic occlusion. Thirty minutes before ischemia, rabbits were subjected to sham intervention or RIPC achieved by bilateral femoral artery occlusion (10 min ischemia/10 min reperfusion, two cycles). Dimethylthiourea (500 mg/kg, intravenously), a hydroxyl radical scavenger, or vehicle was given 1 h before RIPC. Antioxidant enzyme activity was measured along with spinal cord histology and neurologic function. In experiment 2, rabbits were subjected to spinal cord ischemia, with or without RIPC. In addition, rabbits were pretreated with various doses of hexamethonium. RESULTS: RIPC improved neurologic function and reduced histologic damage. This was associated with increased endogenous antioxidant activity. Dimethylthiourea inhibited the protective effects of RIPC. In contrast, there was no effect of hexamethonium on the protective effect of RIPC. CONCLUSIONS: An initial oxidative stress acts as a trigger to upregulate antioxidant enzyme activity, rather than the neural pathway, and plays an important role in the formation of the tolerance against spinal cord ischemia by limb RIPC.

Therapeutic time window of flurbiprofen axetil's neuroprotective effect in a rat model of transient focal cerebral ischemia.

BACKGROUND: The neuroprotective effect of the cyclooxygenase (COX) inhibitor has been demonstrated in acute and chronic neurodegenerative processes. But its function under cerebral ischemic conditions is unclear. This study was designed to evaluate the neuroprotective efficacy of emulsified flurbiprofen axetil (FA, COX inhibitor) and its therapeutic time window in a model of transient middle cerebral artery occlusion (MCAO) in rats. METHODS: Forty-eight male SD rats were randomly assigned into six groups (n = 8 in each group); three FA groups, vehicle, sham and ischemia/reperfusion (I/R) groups. Three doses of FA (5, 10 or 20 mg/kg, intravenous infusion) were administered just after cerebral ischemia/reperfusion (I/R). The degree of neurological outcome was measured by the neurologic deficit score (NDS) at 24, 48 and 72 hours after I/R. Mean brain infarct volume percentage (MBIVP) was determined with 2, 3, 5-triphenyltetrazolium chloride (TTC) staining at 72 hours after I/R. In three other groups (n = 8 in each group), the selected dosage of 10 mg/kg was administrated intravenously at 6, 12 and 24 hours after I/R. RESULTS: The three different doses of FA improved NDS at 24, 48 and 72 hours after I/R and significantly reduced MBIVP. However, the degree of MBIVP in the FA 20 mg/kg group differed from that in FA 10 mg/kg group. Of interest is the finding that the neuroprotective effect conferred by 10 mg/kg of FA was also observed when treatment was delayed until 12 - 24 hours after ischemia reperfusion. CONCLUSION: COX inhibitor FA is a promising therapeutic strategy for cerebral ischemia and its therapeutic time window could last for 12 - 24 hours after cerebral ischemia reperfusion, which would help in lessening the initial ischemic brain damage.

Effect of puerarin on neural function and histopathological damages after transient spinal cord ischemia in rabbits.

OBJECTIVE: To investigate the effect of puerarin on the neural function and the histopathological changes after ischemic spinal cord injury in rabbits. METHODS: Thirty male New Zealand white rabbits were randomly divided into three groups as follows: puerarin group (n=10) receiving intravenous infusion of 30 mg/kg puerarin for 10 minutes, control group (n=10) receiving intravenous infusion of the same volume of normal saline as puerarin for 10 minutes, and sham operation group (n=10) undergoing only the surgical exposure of the abdominal aorta. Temporary spinal cord ischemia was induced by infrarenal aortic occlusion for 20 minutes and followed by reperfusion. The neural status was scored with the Tarlov criteria at 8, 12, 24 and 48 hours after reperfusion. All the animals were killed at 48 hours after reperfusion and the spinal cords (L5) were removed immediately for histopathological study. RESULTS: The neural function scores at 8, 12, 24 and 48 hours after reperfusion were higher in the puerarin group and sham operation group than those in the control group (P<0.05). More normal motor neurons in the anterior horn of spinal cord were present in the puerarin group and sham operation group than those in the control group (P<0.01). There was a strong correlation between the final neural function scores and the number of normal motor neurons in the anterior horn of spinal cord (r=0.839, P<0.01). CONCLUSIONS: Puerarin can significantly ameliorate the neural function and the histopathological damages after transient spinal cord ischemia in rabbits.