Role of Continuous High Thoracic Epidural Anesthesia in Hippocampal Apoptosis after Global Cerebral Ischemia in Rats

Background/Aim: Ischemia/reperfusion (I/R) injury of skeletal muscles is common pathophysiology during surgeries and the superoxide dismutase (SOD) plays a critical role in this process. SOD-modeled coordination compound (MSODa) may simulate the protective effects as SOD. Methods: Therefore, this study was designed to explore the protective effects and underlying mechanism of MSODa on malondialdehyde (MDA) and integrin-β2 (CD11b/CD18) in plasma, myeloperoxidase (MPO) and intercellular cell adhesion molecule-1 (ICAM-1) in tissue, and morphological changes before and after I/R injury. The rat model of I/R in hind limb was established and randomly divided into sham, ischemia, I/R, I/R-treated with saline, SOD, and MSODa, respectively. Results: These results showed that averaged values for MDA, MPO, CD11b/CD18, and ICAM-1 were significantly increased (P < 0.01 vs ischemia alone) in a time-dependent fashion along with marked tissue remodeling, such as abnormal arrangement of muscular fibers, interstitial edema, vasodilation with no-reflow, inflammatory cells adherent and infiltration, structural changes in mitochondrial, and decrease in glycogens as well. However, all parameter changes induced by I/R injury were reversed, at least partially, by MSODa and SOD treatments and intriguingly, the beneficial/protective effects of MSODa was superior to SOD with an early onset. Conclusion: This novel finding demonstrates that MSODa improves I/R injury of skeletal muscles due at least partially to inhibition of adherent molecule expression and reduction of oxygen free radical formation during I/R pathophysiological processes and this protective action of MSODa was superior to SOD, highlighting the bright future for MSODa in clinical management of tissue I/R injury.

Section: I/r Mediated Oxidative Stress In Skeletal Musclementioning

confidence: 99%

Protective Effects of Modeled Superoxide Dismutase Coordination Compound (MSODa) Against Ischemia/Reperfusion Injury in Rat Skeletal Muscle

Wang¹,

Tian²,

Xu³

et al. 2015

“…Hypoxia inducible factor-1 (HIF-1) as an important endogenous signaling protein contributes to pathophysiologic changes of homeostasis under conditions of oxygen deprivation [5][6][7][8][9][10]. Accumulated subunit HIF-1α in the cellular nucleus and cytoplasm modulates the expression of several target genes that involve in neuroprotection, erythropoiesis, and apoptosis modulation [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, inadequate oxygen supply appears in the brain regions during global ischemia, which is associated with ischemiaevoked pathophysiologic changes [13,14]. Recent studies have demonstrated that HIF-1α is expressed in the brain tissues including hippocampus, indicating that HIF-1α is engaged in hippocampal apoptosis after induction of global ischemia [6,[13][14][15]. Using a rat model of asphyxial cardiac arrest (CA), our recent study has further demonstrated that HIF-1α is increased in the hippocampus of rats with CA [16].…”

Section: Introductionmentioning

confidence: 99%

HIF-1α Activation Attenuates IL-6 and TNF-α Pathways in Hippocampus of Rats Following Transient Global Ischemia

Xing

2016

Background/Aims: This study was to examine the role played by hypoxia inducible factor-1 (HIF-1α) in regulating pro-inflammatory cytokines (PICs) pathway in the rat hippocampus after cardiac arrest (CA) induced-transient global ischemia followed by cardiopulmonary resuscitation (CPR). Those PICs include interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Methods: A rat model of CA induced by asphyxia was used in the current study. Following CPR, the hippocampus CA1 region was obtained for ELISA to determine the levels of HIF-1α and PICs; and Western Blot analysis to determine the protein levels of PIC receptors. Results: Our data show that IL-1β, IL-6 and TNF-α were significant elevated in the hippocampus after CPR as compared with control group. This was companied with increasing of HIF-1α and the time courses for HIF-1α and PICs were similar. In addition, PIC receptors, namely IL-1R, IL-6R and TNFR1 were upregulated in CA rats. Also, stimulation of HIF-1α by systemic administration of ML228, HIF-1α activator, significantly attenuated the amplified IL-6/IL-6R and TNF-α /TNFR1 pathway in the hippocampus of CA rats, but did not modify IL-1β and its receptor. Moreover, ML228 attenuated upregulated expression of Caspase-3 indicating cell apoptosis evoked by CA. Conclusion: Transient global ischemia induced by CA increases the levels of IL-1β, IL-6 and TNF-α and thereby leads to enhancement in their respective receptor in the rat hippocampus. Stabilization of HIF-1α plays a role in attenuating amplified expression IL-6R, TNFR1 and Caspase-3 in the processing of transient global ischemia. Results of our study suggest that PICs contribute to cerebral injuries evoked by transient global ischemia and in this pathophysiological process activation of HIF-1α improves tissues against ischemic injuries. Our data revealed specific signaling pathways in alleviating CA-evoked global cerebral ischemia by elucidating that HIF-1α plays an important role in regulating PIC signal pathways and Caspase-3. The subsequent induction of HIF-1α and its target signals is likely a part of the intrinsic neuroprotective effects aimed at attenuating damage as a result of global cerebral ischemia. Thus, targeting one or more of these signaling molecules has clinical implications for treatment and improvement of CA-evoked global cerebral ischemia often observed in clinics.

“…A great deal of evidence has demonstrated that IL-1β and TNF-α play a role mainly via p38 MAPK, ERK and JNK signaling transduction pathways, but IL-6 plays a role via JAK-STAT pathways [27][28][29]. After activation of those signaling pathways, gene transcription occurs [30][31][32]. What different mechanisms by which those signaling transduction pathways are responsible for regulating expression of GAT-1 and GAT-3 via PIC receptors needs to be determined.…”

Section: Discussionmentioning

confidence: 99%

Nefiracetam Attenuates Pro-Inflammatory Cytokines and GABA Transporter in Specific Brain Regions of Rats with Post-Ischemic Seizures

Fu¹,

He²,

Li³

et al. 2015

Background/Aims: Prior studies demonstrated that pro-inflammatory cytokines (PICs) including IL-1β, IL-6 and TNF-α contribute to regulation of epilepsy-associated pathophysiological processes in the specific brain regions, namely the parietal cortex, hippocampus and amygdala. Moreover, GABA transporter type 1 and 3 (GAT-1 and GAT-3) modulating extracellular GABA levels are engaged in the role played by PICs in epileptogenesis. Note that brain ischemic injury also elevates cerebral PICs. Thus, in this report we examined the effects of nefiracetam (NEF), a pyrrolidone derivative, on the levels of IL-1β, IL-6 and TNF-α, and expression of GAT-1 and GAT-3 in the parietal cortex, hippocampus and amygdala using a rat model of post-ischemic nonconvulsive seizure (NCS). Methods: NCS was evoked by the middle cerebral artery occlusion (MCAO). ELISA and Western Blot analysis were employed to determine the levels of PICs and GAT-1/GAT-3, respectively. Results: MCAO significantly increased IL-1β, IL-6 and TNF-α in the parietal cortex, hippocampus and amygdala as compared with sham control animals (P<0.05 vs. control rats). Also, in these specific brain regions expression of GAT-1 and GAT-3 was amplified; and the levels of GABA were decreased in rats following MCAO (P<0.05 vs. control rats). Systemic administration of NEF significantly attenuated the elevated PICs, amplified GAT-1 and GAT-3 as well as impaired GABA. NEF also attenuated the number of NCS events following MCAO. Conclusion: our data demonstrate that NEF improves post-ischemia evoked-NCS by altering PICs, GABA transporters thereby alleviating GABA in the parietal cortex, hippocampus and amygdala. This support a role for PICs and GABA in engagement of the adaptive responses associated with epileptic activity, but also suggests that NEF has anti-epileptic effects via PICs-GABA mechanisms, having pharmacological implications to target the specific PICs for neuronal dysfunction and vulnerability related to post-ischemic seizures and cognitive impairment.