ABSTRACT
OBJECTIVE@#To investigate the protective effects of dexmedetomidine (DEX) against cerebral ischemia/reperfusion (I/R) injury in mice and its relation with mitochondrial fusion and fission.@*METHODS@#Male ICR mice were randomly divided into sham-operated group, I/R group, I/R+DEX group and I/R+DEX+dorsomorphin group. Mouse models of cerebral I/R injury were established by modified thread occlusion of the middle cerebral artery. DEX (50 μg/kg) was injected intraperitoneally at 30 min before cerebral ischemia, which lasted for 1 h followed by reperfusion for 24 h. The neurobehavioral deficits of the mice were evaluated based on Longa's scores. The volume of cerebral infarction was detected by TTC staining. The changes in mitochondrial morphology of the brain cells were observed with transmission electron microscopy. Western blotting was performed to detect the expressions of phosphorylated AMP-activated protein kinase (p-AMPK), mitochondrial fusion protein (Mfn2) and mitochondrial fission protein (p-Drp1) in the brain tissues.@*RESULTS@#DEX pretreatment significantly reduced the neurobehavioral score and the percent volume of cerebral infarction in mice with cerebral I/R injury. Treatment with dorsomorphin (an AMPK inhibitor) in addition to DEX significantly increased the neurobehavioral score and the percent volume of cerebral infarction in the mouse models. Transmission electron microscopy showed that DEX obviously reduced mitochondrial damage caused by cerebral I/R injury and restored mitochondrial morphology of the brain cells, and such effects were abolished by dorsomorphin treatment. Western blotting showed that DEX pretreatment significantly increased the expressions of p-AMPK and Mfn2 protein and decreased the expression of p-Drp1 protein in the brain tissue of the mice, and these changes were also reversed by dorsomorphin treatment.@*CONCLUSIONS@#Preconditioning with DEX produces protective effects against cerebral I/R injury in mice possibly by activating AMPK signaling to regulate mitochondrial fusion and fission in the brain cells.
Subject(s)
Animals , Male , Mice , Brain Ischemia , Dexmedetomidine , Mice, Inbred ICR , Mitochondrial Dynamics , Reperfusion InjuryABSTRACT
OBJECTIVE@#To investigate the effect of connexin43 (Cx43) protein on autophagy in cisplatin (DDP)-resistant testicular cancer I-10 cells.@*METHODS@#The expression of Cx43 proteins in testicular cancer I-10 cells and I-10/DDP cells were detected with Western blotting. I-10/DDP cells were transfected with a full- length mouse Cx43 vector (mCx43) Lipofectamine, the empty vector or Lipofectamine (blank control group), and the changes in the expressions of LC3 and p62 proteins were determined with Western blotting. mCherry-GFP-LC3B transfection and transmission electron microscopy were used to analyze the changes in autophagy of the cells with Cx43 overexpression.@*RESULTS@#Cx43 was significantly decreased in I-10/DDP cells compared with I-10 cells ( < 0.01). Transfection of the I-10/DDP cells with mCx43 vector resulted in significantly increased Cx43 expression in the cells ( < 0.01) and caused significantly decreased expression of LC3-Ⅱ ( < 0.01) and increased expression of p62 ( < 0.05) as compared with the negative control cells. Both transmission electron microscopy and mCherry-GFP-LC3B transfection showed that the number of autophagosomes was obviously reduced in mCx43-transfected cells as compared with the negative control cells.@*CONCLUSIONS@#Cx43 inhibits autophagy in cisplatin-resistant testicular cancer I-10 /DDP cells.