Butylphthalide inhibits ferroptosis and ameliorates cerebral Ischaemia-Reperfusion injury in rats by activating the Nrf2/HO-1 signalling pathway.

This study aims to investigate whether butylphthalide can inhibit ferroptosis and ameliorate cerebral ischaemia-reperfusion (I/R) injury in rats by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) / heme oxygenase-1 (HO-1) signalling pathway, known for its antioxidative and cytoprotective properties. Middle cerebral artery occlusion reperfusion (MCAO/R) rat models were established. Male rats were randomly divided into five groups: a sham-operated group (sham), MCAO/R group, MCAO/R ​+ ​ML385 (Nrf2-specific inhibitor) group, MCAO/R ​+ ​NBP (butylphthalide) group and MCAO/R ​+ ​ML385 ​+ ​NBP group. The effect of butylphthalide on cerebral I/R injury was evaluated using neurological deficit scores. The expression levels of Nrf2, HO-1, glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long-chain family member 4 (ACSL4) and transferrin receptor 1 (TfR1) protein were detected using Western blot. Moreover, the expression levels of GPX4, HO-1 and TfR1 mRNA were determined through real-time fluorescence quantitative reverse transcription polymerase chain reaction. The distribution of Nrf2, HO-1, GPX4 and TfR1 was detected using immunohistochemical staining. The levels of iron and related lipid peroxidation indexes, such as reduced glutathione, reactive oxygen species, malondialdehyde and nitric oxide, were measured using a kit. The changes in mitochondria were observed through transmission electron microscopy. Butylphthalide treatment significantly improved neurological dysfunction, reduced cerebral infarction volume and mitigated histopathological damage in MCAO/R rats. It induced the nuclear translocation of Nrf2 and upregulated HO-1 expression, which was attenuated by ML385. Butylphthalide also attenuated lipid peroxidation, iron accumulation and mitochondrial damage induced by MCAO/R. The expression of GPX4, ACSL4 and TfR1 proteins, as well as their mRNA levels, was modulated through butylphthalide treatment, with improvements observed in mitochondrial morphology. Butylphthalide exerts neuroprotective effects by attenuating neurological dysfunction and ferroptosis in MCAO/R rats through the activation of the Nrf2/HO-1 pathway and inhibition of lipid peroxidation and iron accumulation.

Sun M ，Chen J ，Liu F ，Li P ，Lu J ，Ge S ，Wang L ，Zhang X ，Wang X ... -  《-》

β-Caryophyllene suppresses ferroptosis induced by cerebral ischemia reperfusion via activation of the NRF2/HO-1 signaling pathway in MCAO/R rats.

Ischemic stroke is a complex brain disease regulated by several cell death processes, including apoptosis, autophagy, and ferroptosis. β-Caryophyllene (BCP), a natural bicyclic sesquiterpene abundantly found in essential oils, has been demonstrated to have potential pharmacological benefits in many diseases, including ischemic stroke. This research was to determine the existence of ferroptosis in the pathogenesis of acute ischemic stroke and investigate whether BCP can inhibit ferroptosis to improve cerebral ischemia injury by activating the NRF2/HO-1 signaling pathway in rats. First, we verified ferroptosis by assessing proferroptotic changes after middle cerebral artery occlusion reperfusion (MCAO/R), along with protein and lipid peroxidation levels. Then male rats were divided randomly into Sham, MCAO/R, ML385 (NRF2-specific inhibitor) and BCP groups. The effects of BCP on cerebral injury were detected by the modified neurological severity score, TTC staining, and hematoxylin-eosin staining. We conducted western blotting analyzes of proteins, including those involved in ferroptosis and related signaling pathways. To demonstrate the neuroprotective effect of BCP in vitro, primary astrocytes were pretreated with different concentrations of BCP (10, 20, and 40 μM) for 24 h before oxygen-glucose deprivation/re-oxygenation (ODG/R). We concluded that ferroptosis was engaged in the process of I/R-induced neurological damage, implying that this novel type of cell death might provide new therapeutic options for the clinical treatment of ischemic stroke. In vivo study proved that BCP improved neurological scores, infarct volume, and pathological features after MCAO/R. We demonstrated that BCP evidently enhanced NRF2 nuclear translocation, activated the NRF2/HO-1 pathway, which protected against ferroptosis. In vitro investigation revealed the same results. BCP decreased OGD/R-induced ROS generation and iron accumulation. Furthermore, the neuroprotective effects of BCP were reversed by the NRF2 inhibitor ML385. Our results indicated the critical role of ferroptosis in cerebral I/R injury. For the first time, we showed that the significant neuroprotective effects of BCP in attenuating ischemic stroke injury are correlated with ferroptosis regulation, and its mechanism is associated with activation of the NRF2/HO-1 axis.

Hu Q ，Zuo T ，Deng L ，Chen S ，Yu W ，Liu S ，Liu J ，Wang X ，Fan X ，Dong Z ... -  《-》

Pentoxifylline protects against cerebral ischaemia-reperfusion injury through ferroptosis regulation via the Nrf2/SLC7A11/GPX4 signalling pathway.

To investigate whether pentoxifylline (PTX) attenuates cerebral ischaemia-reperfusion injury (IRI) in rats by inhibiting ferroptosis and to explore the underlying molecular mechanisms. Cerebral IRI was induced in male Sprague-Dawley (SD) rats using middle cerebral artery occlusion (MCAO). The effects of PTX on cerebral ischaemia-reperfusion brain samples were detected through neurological deficit score, staining and electron microscopy; levels of ferroptosis biomarkers from brain samples were detected using kits. Additionally, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), transferrin receptor protein 1, divalent metal transporter 1, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were determined by immunohistochemistry, real-time quantitative polymerase chain reaction and western blotting. Pre-treatment with PTX was found to improve neurological function, evidenced by reduced neurological deficit scores, decreased infarct volume and alleviated pathological features post-MCAO. This improvement was accompanied by reduced lipid peroxidation levels and mitigated mitochondrial damage. Notably, PTX's inhibitory effect on ferroptosis was characterised by enhanced Nrf2 nuclear translocation and regulation of ferroptosis-related proteins. Moreover, inhibition of Nrf2 using ML385 (an Nrf2-specific inhibitor) reversed PTX's neuroprotective effect on MCAO-induced ferroptosis via the SLC7A11/GPX4 signalling pathway. Ferroptosis is evident following cerebral ischaemia-reperfusion in rats. Pentoxifylline confers protection against IRI in rats by inhibiting ferroptosis through the Nrf2/SLC7A11/GPX4 signalling pathway.

Li P ，Chen JM ，Ge SH ，Sun ML ，Lu JD ，Liu F ，Wang LL ，Zhang X ，Wang XP ... -  《-》

Edaravone dexborneol protects against cerebral ischemia/reperfusion-induced blood-brain barrier damage by inhibiting ferroptosis via activation of nrf-2/HO-1/GPX4 signaling.

Ferroptosis has recently been recognized as a mechanism of cerebral ischemia-reperfusion (I/R) injury, attributed to blood-brain barrier (BBB) disruption. Edaravone dexboneol (Eda.B) is a novel neuroprotective agent widely employed in ischemic stroke, which is composed of edaravone (Eda) and dexborneol. This study aimed to investigate the protective effects of Eda.B on the BBB in cerebral I/R and explore its potential mechanisms. Transient middle cerebral artery occlusion (tMCAO) Sprague-Dawley-rats model was used. Rats were randomly assigned to sham-operated group (sham, n = 20), model group (tMCAO, n = 20), Eda.B group (Eda.B, n = 20), Eda group (Eda, n = 20) and dexborneol group (dexborneol, n = 20), and Eda.B + Zinc protoporphyria group (Eda.B + ZnPP, n = 5). Infarct area, cellular apoptosis and neurofunctional recovery were accessed through TTC staining, TUNEL staining, and modified Garcia scoring system, respectively. BBB integrity was evaluated via Evans blue staining. Nuclear factor E2 related factor 2 (Nrf-2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) signaling were qualified by Western blot. Transmission electron microscopy (TEM) revealed alterations in ipsilateral brain tissue among groups. Glutathione (GSH) and malondialdehyde (MDA) levels, and Fe2+ tissue content determination were detected. Eda.B effectively improved neurological deficits, diminished infarct area and cellular apoptosis, as well as ameliorated BBB integrity in tMCAO rats. Further, Eda.B significantly inhibited ferroptosis, as evidenced by ameliorated pathological features of mitochondria, down-regulated of MDA and Fe2+ levels and up-regulated GSH content. Mechanistically, Eda.B attenuated BBB disruption via Nrf-2-mediated ferroptosis, promoting nuclear translocation of Nrf-2, increasing HO-1, GPX4 expression, alleviating the loss of zonula occludens 1 (ZO-1) and occludin as well as decreasing 4-hydroxynonenal (4-HNE) level. This study revealed for the first time that Eda.B safeguarded the BBB from cerebral I/R injury by inhibiting ferroptosis through the activation of the Nrf-2/HO-1/GPX4 axis, providing a novel insight into the neuroprotective effect of Eda.B in cerebral I/R.

Xiao P ，Huang H ，Zhao H ，Liu R ，Sun Z ，Liu Y ，Chen N ，Zhang Z ... -  《-》

Loureirin C inhibits ferroptosis after cerebral ischemia reperfusion through regulation of the Nrf2 pathway in mice.

Ischemic stroke (IS) is considered as a serious cerebral vascular disease. Ferroptosis is a novel type of regulated cell death (RCD), that closely related to the occurrence and progress of IS. Loureirin C, a type of dihydrochalcone compound derived from the Chinese Dragon's blood (CDB). The effective components extracted from CDB have shown neuroprotective effects in ischemia reperfusion models. However, the role of Loureirin C in mice after IS is not well understood. Thus, it is worth to identify the effect and mechanism of Loureirin C on IS. The present research aims to prove the existence of ferroptosis in IS and explore whether Loureirin C can inhibit ferroptosis by regulating nuclear factor E2 related factor 2 (Nrf2) pathway in mice and exert neuroprotective effects on IS models. Middle cerebral artery occlusion and reperfusion (MCAO/R) model was established to evaluate the occurrence of ferroptosis and the potential Loureirin C brain-protective effect in vivo. The analysis of free iron, glutamate content, reactive oxygen species (ROS) and lipid peroxidation levels, along with transmission electron microscope (TEM) was applied to prove the existence of ferroptosis. The function of Loureirin C on Nrf2 nuclear translocation was verified by immunofluorescence staining. In vitro, primary neurons and SH-SY5Y cells were processed with Loureirin C after oxygen and glucose deprivation-reperfusion (OGD/R). ELISA kits, western blotting, co-immunoprecipitation (Co-IP) analysis, immunofluorescence, and quantitative real-time PCR were devoted to proving the neuroprotective effects of Loureirin C on IS via regulating ferroptosis and Nrf2 pathways. The results showed that Loureirin C not only dramatically alleviated brain injury and inhibited neurons ferroptosis in mice after MCAO/R, but also dose-dependently reduce ROS accumulation in ferroptosis after OGD/R. Further, Loureirin C inhibits ferroptosis by activating Nrf2 pathway, and promoting nuclear translocation of Nrf2. Besides, Loureirin C increases heme oxygenase 1 (HO-1), quinone oxidoreductase 1 (NQO1) and glutathione peroxidase 4 (GPX4) content after IS. Intriguingly, the anti-ferroptosis effect of Loureirin C is weakened by Nrf2 knockdown. Our discoveries first revealed that the inhibitory action of Loureirin C on ferroptosis may greatly depend on its adjusting effect on the Nrf2 pathway, suggesting that Loureirin C could act as a novel anti-ferroptosis candidate and play a therapeutic role in IS. These novel discoveries on the role of Loureirin C on IS models reveal an innovative method that may contribute to neuroprotection for the prevention of IS.

Liu Y ，Mi Y ，Wang Y ，Meng Q ，Xu L ，Liu Y ，Zhou D ，Wang Y ，Liang D ，Li W ，Li N ，Hou Y ... -  《-》