Mitophagy mediated by ligustilide relieves OGD/R-induced injury in HT22 cells / 中国中药杂志

Mitochondrion, as the main energy-supply organelle, is the key target region that determines neuronal survival and death during ischemia. When an ischemic stroke occurs, timely removal of damaged mitochondria is very important for improving mitochondrial function and repairing nerve damage. This study investigated the effect of ligustilide(LIG), an active ingredient of Chinese medicine, on mitochondrial function and mitophagy based on the oxygen and glucose deprivation/reperfusion(OGD/R)-induced injury model in HT22 cells. By OGD/R-induced injury model was induced in vitro, HT22 cells were pre-treated with LIG for 3 h, and the cell viability was detected by the CCK-8 assay. Immunofluorescence and flow cytometry were used to detect indicators related to mitochondrial function, such as mitochondrial membrane potential, calcium overload, and reactive oxygen species(ROS). Western blot was used to detect the expression of dynamin-related protein 1(Drp1, mitochondrial fission protein) and cleaved caspase-3(apoptotic protein). Immunofluorescence was used to observe the co-localization of the translocase of outer mitochondrial membrane 20(TOMM20, mitochondrial marker) and lysosome-associated membrane protein 2(LAMP2, autophagy marker). The results showed that LIG increased the cell viability of HT22 cells as compared with the conditions in the model group. Furthermore, LIG also inhibited the ROS release, calcium overload, and the decrease in mitochondrial membrane potential in HT22 cells after OGD/R-induced injury, facilitated Drp1 expression, and promoted the co-localization of TOMM20 and LAMP2. The findings indicate that LIG can improve the mitochondrial function after OGD/R-induced injury and promote mitophagy. When mitophagy inhibitor mdivi-1 was administered, the expression of apoptotic protein increased, suggesting that the neuroprotective effect of LIG may be related to the promotion of mitophagy.

Effect of ligustilide on oxygen and glucose deprivation/reperfusion-induced mitochondria fission in PC12 cells / 中国中药杂志

This study aimed to investigate the effect and mechanism of ligustilide, the main active ingredient in Ligusticum wallichii, on mitochondria fission after PC12 cell injury induced by oxygen and glucose deprivation/reperfusion(OGD/R). In the experiment, an OGD/R model was established in vitro, and PC12 cells were pre-treated with ligustilide for 3 h, and then the cell viability was detected by CCK-8 method. The effect of different concentrations of ligustilide on the morphology of PC12 cells after OGD/R injury was observed under an inverted microscope. Transmission electron microscopy was used to observe the mitochondrial fission of PC12 cells after OGD/R injury. DCFH-DA immunofluorescence staining method was used to detect intracellular reactive oxygen species(ROS) changes. Changes in mitochondria membrane potential(MMP) were detected by flow cytometry. Hochest 33258 was used to observe the apoptosis of PC12 cells. Western blot was used to detect changes in cytochrome C(Cyt C) content in mitochondria and cytoplasm, and mitochondrial fission-related proteins Drp 1 and Fis 1. All results showed that compared with the model group, ligustilide significantly increased the survival rate of PC12 cells and the number of cells. Further experiments showed that ligustilide inhibited the release of ROS and decline of mitochondrial membrane potential in PC12 cells after OGD/R injury. Moreover, ligustilide reduced the release of Cyt C and promoted the expressions of Drp1 and Fis1 in mitochondrial fission proteins. Verification experiments showed that mitochondrial fission inhibitor mdivi-1 decreased cell survival rate and inhibited fission. The results indicated that ligustilide exerted neuro-protective effects by promoting mitochondrial fission and reducing cell damage. It preliminary proves that the mechanism of ligustilide on ischemic brain injury may be related to the promotion of mitochondrial fission and the maintenance of cell homeostasis.