ABSTRACT
The aim of this study is to explore the mechanism of ligustilide, the main active constituent of essential oils of traditional Chinese medicine Angelicae Sinensis Radix, on alleviating oxygen-glucose deprivation/reperfusion(OGD/R) injury in PC12 cells from the perspective of ferroptosis. OGD/R was induced in vitro, and 12 h after ligustilide addition during reperfusion, cell viability was detected by cell counting kit-8(CCK-8) assay. DCFH-DA staining was used to detect the level of intracellular reactive oxygen species(ROS). Western blot was employed to detect the expression of ferroptosis-related proteins, glutathione peroxidase 4(GPX4), transferrin receptor 1(TFR1), and solute carrier family 7 member 11(SLC7A11), and ferritinophagy-related proteins, nuclear receptor coactivator 4(NCOA4), ferritin heavy chain 1(FTH1), and microtubule-associated protein 1 light chain 3(LC3). The fluorescence intensity of LC3 protein was analyzed by immunofluorescence staining. The content of glutathione(GSH), malondialdehyde(MDA), and Fe was detected by chemiluminescent immunoassay. The effect of ligustilide on ferroptosis was observed by overexpression of NCOA4 gene. The results showed that ligustilide increased the viability of PC12 cells damaged by OGD/R, inhibited the release of ROS, reduced the content of Fe and MDA and the expression of TFR1, NCOA4, and LC3, and improved the content of GSH and the expression of GPX4, SLC7A11, and FTH1 compared with OGD/R group. After overexpression of the key protein NCOA4 in ferritinophagy, the inhibitory effect of ligustilide on ferroptosis was partially reversed, indicating that ligustilide may alleviate OGD/R injury of PC12 cells by blocking ferritinophagy and then inhibiting ferroptosis. The mechanism by which ligustilide reduced OGD/R injury in PC12 cells is that it suppressed the ferroptosis involved in ferritinophagy.
Subject(s)
Animals , Rats , PC12 Cells , Ferroptosis/genetics , Reactive Oxygen Species , Transcription Factors , GlutathioneABSTRACT
OBJECTIVE To explore the effect of total flavonoids of Rhododendra simsii (TFR) on improving cerebral ischemia/reperfusion injury (CIRI) and its relationship with STIM/Orai-regulated operational Ca2+influx (SOCE) pathway. METHODS Oxygen-glucose deprivation/reoxygenation (OGD/R) PC12 cells were used to simulate CIRI in vitro, and the intracellular Ca2+ concentration and apoptosis rate of PC12 cells were detected by laser confocal microscope and flow cytometry, respectively. The regulation of STIM/Orai on SOCE was analyzed by STIM/Orai gene silencing and STIM/Orai gene overexpression. The CIRI model was established by MCAO in SD rats. The activities of inflammatory cyto?kines IL-1, IL-6 and TNF-αin serum were detected by ELISA. The pathological changes of ischemic brain tissue and the infarction of rat brain tissue were detected by HE staining and TTC staining. The protein and mRNA expression levels of STIM1, STIM2, Orai1, caspase-3 and PKB in brain tissue were detected by Western blotting and RT-qPCR, respectively. RESULTS The results of in vitro experiment showed that the fluorescence intensity of Ca2+ and apoptosis rate in PC12 cells treated with TFR were significantly lower than those in OGD/R group, and this trend was enhanced by SOCE antagonist 2-APB. STIM1/STIM2/Orai1 gene silencing significantly reduced apoptosis and Ca2+overload in OGD/R model, while TFR combined with overexpression of STIM1/STIM2/Orai1 aggravated apoptosis and Ca2+overload. In the in vivo experiment, TFR significantly reduced the brain histopathological damage, infarction of brain tissue, the contents of IL-1, IL-6 and TNF-α in the serum in MCAO rats and down-regulated the expression of STIM1, STIM2, Orai1 and caspase-3 protein and mRNA in the brain tissue, and up-regulated the expression of PKB. The above effects were enhanced by the addition of 2-APB. CONCLUSION The above results indicate that TFR may reduce the contents of inflammatory factors and apoptosis, decrease Ca2+ overload and ameliorate brain injury by inhibiting SOCE pathway mediated by STIM and Orai, suggesting that it has a protective effect against subacute CIRI.