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Aim To investigate the mechanism by which ginsenoside Rgl regulates autophagy anrl delays brain aging in mice through AMPK/mTOR signaling pathway.Methods C57BL/6J male mice were ran¬domly divided into four groups, namely brain aging model group ,control group, Rgl anti-aging group,auto¬phagy activator Rapamycin anti-aging group.After the modeling was completed, the test of each experimental index would be carried out on the next day.Morris wa¬ter maze experiment was used to detect the learning and memory ability of mice.Paraffin sections of the hippocampus were prepared, HE , Nissl and immunohis- tochemical staining were used to observe the morpholo¬gy of hippocampal neurons, the number of neurons and Nissl bodies was counted, and autophagy-related proteins p62 , ATG5 , ULK1 were detected.Brain tissue homogenates were prepared to detect the aetivity of brain tissue acetylcholinesterase ( AChE ).Western blot was userl to detect brain tissue autophagy-related proteins LC3II, P62, beclinl, P-AMPK/AMPK, P- mTOR/mTOR and apoptosis protein P53.Results Water maze test showed that Rgl and Hap significantly improved the learning and memory abilities of brain-ag¬ing mice.HE and Nissl staining showed that Rgl and Rap decreased necrotic cells and increased the number of Nissl bodies in the hippocampus of brain-aging mice.Immunohistochemistry staining showed that Rgl and Rap decreased the expression of neuronal autoph- agv protein P62 in hippocampus and increased the ex-pression of ATG5 and ULK1.Rgl and Rap decreased the activity of AhcE in brain-aging mice.Western blot showed that Rgl and Rap increased autophagy-related proteins LC3II, Beclinl , P-AMPK/AMPK, but de¬creased the expression of P-mTOR/mTOR, P62, P53.Conclusions Ginsenoside Rgl can effectively antago¬nize the aging effect of D-gal on mouse brain.The pos¬sible mechanism is related to the regulation of autoph- agv by Rgl through AMPK/mTOR signaling pathway.
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ATG5 and BECLIN-1 belong to two kind of crucial autophagy-related proteins included the formation of autoph-agosomes,in addition to the promotion of autophagy,enhances susceptibility towards apoptotic stimuli,therefore,ATG5 and BECLIN-1 are considered to be a molecular link between autophagy and apoptosis.Preliminary data revealed that ATG5 media-ted the formation of autophagosomes by ATG5-ATG12-ATG16L ubiquitination system,while BECLIN-1 induces autophagy by phosphatidylino3-kinase (PtdIns3KC3)complex.But now it is believed that truncated ATG5(tATG5-N)and truncated BEC-LIN-1(BECLIN-1-C),an amino-terminal cleavage product of ATG5 and carboxyl-terminal cleavage product of BECLIN-1, could induce apoptosis.The research summarize the progress on ATG5 and BECLIN-1 regulated autophagy and apoptosis,so as to further reveal the molecular mechanism of they regulate autophagy and apoptosis.
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Objective @#To explore the regulatory effects of ResolvinD1 (RVD1) on autophagy and apoptosis of cardiomyocytes in aging rats , and the effects of RVD1 on mitochondria⁃associated endoplasmic reticulum membranes (MAMs) of myocardial tissue . @*Methods @#Thirty 18⁃month⁃old SD rats were randomly divided into model group , low⁃dose RVD1 group and high⁃dose RVD1 group , with 10 rats in each group , and another 10 6 ⁃month⁃old SD rats were selected as control group . The low⁃dose RVD1 group and high⁃dose RVD1 group were injected with 50 ng/ml and 100 ng/ml RVD1 through the tail vein , respectively , control group and model group were injected with the same amount of phosphate buffered saline (PBS) for 21 days . The β ⁃galactosidase activity of rat myocardial tissue was determined by p ⁃nitrophenol method , the histopathological changes of rat myocardial tissue were detected by hematoxylin⁃eosin (HE) staining , and the collagen deposition in rat myocardial tissue was observed by Masson staining , apoptosis of rat myocardial cells was detected by dUTP in situ end labeling mediated by terminal deoxynucleotide transferase(TUNEL) , the expression of autophagy marker microtubule⁃associated protein 3 (LC3) was detecotide transferase(TUNEL) , the expression of autophagy marker microtubule⁃associated protein 3 (LC3) was detected by immunohistochemical S ⁃P method , the ratio of LC3 ⁃ Ⅱ/LC3 ⁃ Ⅰ and the expression of Beclin⁃1 , p62 in rat myocardial tissue were determined by Western blot , the structure of MAMs in rat myocardial tissue was observed by transmission electron microscopy , the expression levels of glucose⁃regulatory protein 75 (GRP75) , volt⁃dependent anion channel 1 (VDAC1) and mitochondrial fusion protein 2 (Mfn2) in rat myocardial tissue were determined by Western blot .@*Results @#Compared with model group , β ⁃galactosidase activity of myocardial tissue decreased in low⁃dose RVD1 group and high⁃dose RVD1 group (P < 0. 05) , myocardial fiber breakage and myocardial cell damag were significantly alleviated , collagen fiber deposition was significantly reduced , and the proportion of TUNEL positive cells in myocardial tissue decreased (P < 0. 05) , the positive rate of LC3 protein increased (P < 0. 05) , the ratio of LC3 ⁃ Ⅱ/LC3 ⁃ Ⅰ increased , the relative expression level of Beclin⁃1 protein was up⁃regulated and the relative expression level of p62 protein was down⁃regulated ( P < 0. 05) , the structure of MAMs was tighter , and the percentage of MAMs in mitochondrial circumference also increased (P < 0. 05) , the relative protein expressions of GRP75 , VDAC1 and Mfn2 were up⁃regulated (P < 0. 05) . Compared with low⁃dose RVD1 group , β ⁃galactosidase activity in high⁃dose RVD1 group further decreased ( P < 0. 05) , no obvious damage was observed in myocardial tissue , collagen fiber deposition was further decreased , the proportion of TUNEL positive cells in myocardial tissue decreased (P < 0. 05 ) , and the positive rate of LC3 protein increased ( P < 0. 05 ) , LC3 ⁃ Ⅱ/LC3 ⁃ Ⅰ ratio increased , Beclin⁃1 relative expression level was up⁃regulated and p62 relative expression level was down⁃regulated (P < 0. 05) , the structure of MAMs was more compact , and their percentage in mitochondrial circumference further increased (P < 0. 05 ) , the relative expressions of GRP75 , VDAC1 and Mfn2 were further up⁃regulated ( P <0. 05) . @*Conclusion @#RVD1 can activate autophagy , alleviate myocardial apoptosis and collagen fiber deposition, and promote mitochondria⁃associated endoplasmic reticulum membranes in aging rats .
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Aim To investigate the effect of asiatic acid on apoptosis and autophagy in human glioblastoma T98G cells. Methods MTT colorimetry was employed to assay the cellular proliferating activity. The fluores-cence microscope and Hoechst 33258 staining were used to detect the morphological changes. The cell ap-optosis and autophagy were analyzed by flow cytometry with Annexin-V/7-AAD and MDC staining respective-ly. The expressions of associated proteins were detected by Western blot to analyze the mechanism of apoptosis and autophagy. Results MTT assay showed that the growth of T 9 8 G cells was inhibited by asiatic acid ( IC50 =46. 3 μmol · L-1 ) . Annexin V/7-AAD stai-ning and Western blot revealed that asiatic acid in-duced apoptosis in T98 G cells by reducing the expres-sion of Akt, decreasing the mitochondrial membrane potential, and increasing the expression of Caspase-3. MDC staining and Western blot showed that the per-centage of MDC-positive cells was decreased and the expressions of Beclin-1 , LC3-II and Atgs were inhibi-ted by asiatic acid treatment. 5 μmol·L-1 chloroquine was used to up-regulate the expressions of LC3-Ⅱand Beclin-1 . Asiatic acid-inhibited autophagy was blocked and the total apoptotic rate was reduced remarkably. Conclusion Asiatic acid suppresses T98 G cells pro-liferation by inducing apoptosis and inhibiting cell au-tophagy, and the very role of inhibiting autophagy could promote apoptosis to a certain extent.