Post Stroke Safinamide Treatment Attenuates Neurological Damage by Modulating Autophagy and Apoptosis in Experimental Model of Stroke in Rats

Sophoricoside ameliorates cerebral ischemia-reperfusion injury dependent on activating AMPK

AIMS

Ischemic stroke accounts for 87% of all strokes, and its death and disability bring a huge burden to society. Brain injury caused by ischemia-reperfusion (I/R) is also a major difficulty in clinical treatment and prognosis. Sophoricoside (SOP) is an isoflavone glycoside isolated from the seed of medical herb Sophora japonica L. Previously, SOP was found to be effective in anti-inflammation and glucose-lipid metabolism-related diseases. In order to investigate whether SOP has a regulatory effect on cerebral I/R injury, we conducted this study.

METHODS

Here, by application of SOP into MCAO (transient middle cerebral artery occlusion)-induced mice and OGD/R (oxygen glucose deprivation/reperfusion)-induced primary neurons, the regulation effects of SOP was analyzed by detecting neurological score of post-stroke mice, phenotypes of brains and brain sections, cell viabilities, and apoptosis- and inflammation-regulation. RNA sequencing and molecular biology experiments were performed to explore the mechanism of SOP regulating cerebral I/R injury.

RESULTS

SOP administration decreased the infarct size, neurological deficit score, neuronal cell injury, inflammation and apoptosis. Mechanistically, SOP exerted its protective effect by activating the AMP-activated protein kinase (AMPK) signaling pathway.

CONCLUSION

SOP inhibits cerebral I/R injury by promoting the phosphorylation of AMPK.

AMPA receptor modulation through sequential treatment with perampanel and aniracetam mitigates post-stroke damage in experimental model of ischemic stroke

The present study evaluates the effect of modulating α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) by inhibiting them in the acute phase and activating them in the sub-acute phase on post-stroke recovery in middle cerebral artery occlusion (MCAo) model of stroke in rats. After 90 min of MCAo, perampanel (an AMPAR antagonist, 1.5 mg/kg i.p) and aniracetam (an AMPA agonist, 50 mg/kg i.p.) were administered for different durations after MCAo. Later, after obtaining the best time point for the antagonist and the agonist treatment protocols, sequential treatment with perampanel and aniracetam were given, and the effect on neurological damage and post stroke recovery were assessed. Perampanel and aniracetam significantly protected MCAo-induced neurological damage and diminished the infarct percentage. Furthermore, treatment with these study drugs improved the motor coordination and grip strength. Sequential treatment with perampanel and aniracetam reduced the infarct percentage as assessed by MRI. Moreover, these compounds diminished the inflammation via reducing the levels of pro-inflammatory cytokines (TNF-α, IL-1β) and increasing the levels of anti-inflammatory cytokine (IL-10) along with reductions in GFAP expression. Moreover, the neuroprotective markers (BDNF and TrkB) were found to be significantly increased. Levels of apoptotic markers (Bax, cleaved-caspase-3; Bcl2 and TUNEL positive cells) and neuronal damage (MAP-2) were normalized with the AMPA antagonist and agonist treatment. Expressions of GluR1 and GluR2 subunits of AMPAR were significantly enhanced with sequential treatment. The present study thus showed that modulation of AMPAR improves neurobehavioral deficits and reduces the infarct percentage through anti-inflammatory, neuroprotective and anti-apoptotic effects.

Decanoic acid mitigates ischemia reperfusion injury by modulating neuroprotective, inflammatory and oxidative pathways in middle cerebral artery occlusion model of stroke in rats

OBJECTIVE

Amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) is an ionotropic transmembrane receptor for glutamate. AMPA receptor blockers have been reported to prevent neurological damage and enhance the post stroke recovery in rats. Decanoic acid, a medium-chain fatty acid, has been reported to exhibit non-competitive AMPA receptor antagonism. This study evaluated the effect of decanoic acid administered before and after ischemia reperfusion injury on neurological damage and post stroke recovery in rats.

METHODS

Middle cerebral artery occlusion (MCAo) was performed by using the intraluminal method to induce focal cerebral ischemia. Decanoic acid (120 mg/kg) was administered orally for 1 day (5-10 min post reperfusion) in one group and for 2 days (24 h pre and 5-10 min post reperfusion) in the other group. Effect on neurological damage and post stroke recovery was assessed by neurobehavioral parameters, MRI and TTC staining along with inflammatory, oxidative, apoptotic, and neuroprotective biomarkers.

RESULTS

Decanoic acid significantly reduced the MCAo induced neurological damage and infarct size. Decanoic acid treatment increased the motor coordination and grip strength. Furthermore, levels of inflammatory (TNFα, IL-1β and IL-6), oxidative stress (MDA), apoptotic (TUNEL positive cells) and neurological injury (GFAP) biomarkers were reduced after decanoic acid treatment. Anti-inflammatory cytokine (IL-10) and neuroprotective markers (NT-3, BDNF and TrkB) were found to be significantly increased with decanoic acid treatment.

CONCLUSION

This study showed protective effects of decanoic acid against ischemia reperfusion injury in rats. Anti-inflammatory, antioxidant, neuroprotective, and anti-apoptotic properties may be responsible for the beneficial effects of decanoic acid observed in the study.

Dexmedetomidine alleviates cerebral ischemia-reperfusion injury via inhibiting autophagy through PI3K/Akt/mTOR pathway

Dexmedetomidine has been shown to protect against cerebral ischemia-reperfusion injury (CIRI). Nevertheless, the precise mechanism is obscure. In order to explore the effect of dexmedetomidine pre-conditioning on autophagy against CIRI in rats, middle cerebral artery occlusion (MCAO) was conducted to establish cerebral ischemia-reperfusion (I/R) model in male SD rats with 2 h ischemia and 24 h reperfusion. Dexmedetomidine was delivered to rats at 10, 50 and 100 µg/kg doses respectively, and LY294002, a PI3K/Akt/mTOR pathway inhibitor, was administered at 10 mg/kg intraperitoneally 30 min before MCAO. Neurological deficit score was assessed and cerebral infarct size was detected by TTC staining. Morris water maze (MWM) was performed to estimate spatial learning and memory ability. Furthermore, to detect activity of PI3K/Akt/mTOR pathway and autophagy, p-Akt, p-mTOR, Beclin-1 and LC3 were measured by western blot. Our findings revealed that 50 and 100 µg/kg of dexmedetomidine pretreatment could improve the neurological deficit score and reduce cerebral infarct size after CIRI, while these effects were markedly suppressed by LY294002. In MWM test, dexmedetomidine was confirmed to shorten escape latency and increase times across platform after CIRI. Nevertheless, LY294002 pretreatment eliminated the improvement of dexmedetomidine on spatial learning and memory ability. Furthermore, dexmedetomidine pretreatment reduced ratios of Beclin-1 and LC3II/LC3I and elevated p-Akt/Akt and p-mTOR/mTOR after CIRI. However, above effects of dexmedetomidine were partly reversed by LY294002. Overall, dexmedetomidine pretreatment exerted neuroprotection against CIRI in rats by attenuating autophagy via the PI3K/Akt/mTOR pathway.

The autophagy in ischemic stroke: A regulatory role of non-coding-RNAs

Ischemic stroke (IS) is a central nervous system neurological disorder ascribed to an acute focal trauma, with high mortality and disability, leading to a heavy burden on family and society. Autophagy is a self-digesting process by which damaged organelles and useless proteins are recycled to maintain cellular homeostasis, and plays a pivotal role in the process of IS. Non-coding RNAs (ncRNAs), mainly contains microRNA, long non-coding RNA and circular RNA, have been extensively investigated on regulation of autophagy in human diseases. Recent studies have implied that ncRNAs-regulating autophagy participates in pathophysiological process of IS, including cell apoptosis, inflammation, oxidative stress, blood-brain barrier damage and glial activation, which indicates that regulating autophagy by ncRNAs may be beneficial for IS treatment. This review summarizes the role of autophagy in IS, as well as focuses on the role of ncRNAs-mediated autophagy in IS, for the development of potential therapeutic strategies in this disease.

Macamide B Pretreatment Attenuates Neonatal Hypoxic-Ischemic Brain Damage of Mice Induced Apoptosis and Regulates Autophagy via the PI3K/AKT Signaling Pathway

Lepidium meyenii (maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb possesses antioxidant and antiapoptotic activities, enhances autophagy functions, prevents cell death, and protects neurons from ischemic damage. Macamide B, an effective active ingredient of maca, exerts a neuroprotective effect on neonatal hypoxic-ischemic brain damage (HIBD), but the mechanism underlying its neuroprotective effect is not yet known. The purpose of this study was to explore the effect of macamide B on HIBD-induced autophagy and apoptosis and its potential neuroprotective mechanism. The modified Rice-Vannucci method was used to induce HIBD in 7-day-old (P7) macamide B- and vehicle-pretreated pups. TTC staining was performed to evaluate the cerebral infarct volume in pups, the brain water content was measured to evaluate the neurological function of pups, neurobehavioural testing was conducted to assess functional recovery after HIBD, TUNEL and FJC staining was performed to detect cellular autophagy and apoptosis, and Western blot analysis was used to detect the levels of proteins in the pro-survival phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway and autophagy and apoptosis-related proteins. Macamide B pretreatment significantly decreases brain damage and improves the recovery of neural function after HIBD. At the same time, macamide B pretreatment activates the PI3K/AKT signaling pathway after HIBD, enhances autophagy, and reduces hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of the PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that a macamide B pretreatment might regulate autophagy through the PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.