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Objective To evaluate the effect of propofol pretreatment on dephosphorylation of phospho-dynamin-related protein 1 (p-Drp1) Ser637 during kidney injury induced by hepatic ischemia-reperfusion (I/R) in mice.Methods Thirty healthy SPF male C57 mice,weighing 20-25 g,were divided into 3 groups (n=10 each) using a random number table method:sham operation group (group S),hepatic I/R group (group HI/R) and propofol pretreatment group (group P).Hepatic I/R was produced by occluding the blood supply to the left lateral and median lobes of liver for 60 min followed by reperfusion in anesthetized mice.In group P,1％ propofol 30 mg/kg was intraperitoneally injected at 30 min before operation,while the equal volume of normal saline was given instead in S and HI/R groups.Blood samples were collected from the left ventricle at 6 h of reperfusion for determination of the concentrations of serum blood urea nitrogen (BUN) and creatinine (Cr).Renal tissues were obtained for determination of cell apoptosis (by TUNEL) and expression of Drp1,p-Drp1 Ser637,cytochrome c (Cyt c) and cleaved caspase-3 (by Western blot) and for examination of the ultrastructure of mitochondria (by transmission electron microscopy).Apoptosis index was calculated.Results Compared with group S,the serum BUN and Cr concentrations and apoptosis index were significantly increased,the expression of p-Drp1 Ser637 was down-regulated,and the expression of Cyt c and cleaved caspase-3 was up-regulated (P＜0.05),and microscopic examination showed that mitochondria was swollen with vacuolization and mitochondrial cristae was irregularly distributed or disrupted and shortened in HI/R and P groups.Compared with group HI/R,serum BUN and Cr concentrations and apoptosis index were significantly decreased,the expression of p-Drp1 Ser637 was up-regulated,the expression of Cyt c and cleaved caspase-3 was down-regulated (P＜0.05),and the ultrastructure of mitochondria was markedly improved in group P.There was no significant difference in the expression of Drp1 in renal issues between the three groups (P＞0.05).Conclusion The mechanism by which propofol pretreatment mitigates hepatic I/R-induced kidney injury is related to inhibiting dephosphorylation of Drpl Ser637 in mice.
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Objective To evaluate the effect of electroacupuncture (EA) preconditioning on the activity of dynamin-related protein 1 (Drp1) in brain tissues during cerebral ischemia-reperfusion (I/R) in rats.Methods A total of 126 pathogen-free healthy adult male Wistar rats,weighing 250-300 g,were divided into 3 groups (n =42 each) using a random number table:sham operation group (group S),group I/R and EA preconditioning group (group EA).In group S,the blood vessels were only separated but not occluded.In group I/R,a nylon thread with rounded tip was inserted into the left middle cerebral artery advanced cranially until resistance was met,and middle cerebral artery occlusion was maintained for 2 h followed by reperfusion.In group EA,Baihui acupoints were stimulated with an electric stimulator (2/ 15 Hz disperse-dense waves,intensity 1 mA) for 30 min,lasting for 5 consecutive days,and the model of focal cerebral I/R was established at 24 h after the last stimulation.At 6,24 and 48 h of reperfusion,the neurologic deficit was assessed and scored,the mitochondria in the cerebral cortex on the ischemic side were extracted,the expression of Drpl in mitochondria was detected using Western blot,the mitochondrial uhrastructure was examined with an electron microscope,and neuroapoptosis was measured using TUNEL.The apoptosis rate was calculated.Results Compared with group S,the neurological deficit score and apoptosis rate were significantly increased,and the expression of Drpl in mitochondria was up-regulated at each time point in I/R and EA groups (P＜0.05).Compared with group I/R,the neurological deficit score and apoptosis rate were significantly decreased,and the expression of Drpl in mitochondria was down-regulated at each time point in group EA (P＜0.05).Conclusion The mechanism by which EA preconditioning reduces cerebral I/R injury may be related to inhibiting the activity of Drpl and thus inhibiting the excessive fission of mitochondria in rats.
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Objective To evaluate the effect of hypothermia on the expression of dynamin?related protein 1 ( Drp1) in brain tissues during global cerebral ischemia?reperfusion ( I∕R) in rats. Methods Thirty?six healthy male Sprague?Dawley rats, weighing 280-320 g, were divided into 3 groups ( n=12 each) using a random number table: sham operation group ( group Sham ) , global cerebral I∕R group ( group I∕R) and hypothermia group ( group H) . Cardiac arrest was induced by transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I∕R model in anesthetized rats in I∕R and H groups. In group H, the body temperature ( rectal temperature) was cooled down to 32-34 ℃ within 15 min starting from the beginning of reperfusion, and maintained at this level for 6 h. At 72 h of reperfusion, neurological deficit was scored, and the rats were sacrificed, and the whole brain was removed for examination of the pathological changes in hippocampal CA1 region and for determination of nor?mal pyramidal cell count and neuronal apoptosis in hippocampal CA1 region and expression of Drp1 and cy?tochrome c (Cyt c) in hippocampal tissues (by Western blot). The apoptosis rate was calculated. Re?sults Compared with group S, the neurological deficit score and apoptosis rate were significantly in?creased, and the number of normal pyramidal cells was decreased in I∕R and H groups, the expression of Drp1 and Cyt c in hippocampal tissues was significantly up?regulated in group I∕R ( P0.05) . Compared with group I∕R, the neurological deficit score and apoptosis rate were significantly de?creased, the number of normal pyramidal cells was increased, and the expression of Drp1 and Cyt c in hip?pocampal tissues was down?regulated in group H ( P<0.05) . Conclusion The mechanism by which hypo?thermia inhibits cell apoptosis during global cerebral I∕R may be related to down?regulation of Drp1 expres?sion in rats.
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Dynamin-related protein 1 (Drpl) is a major protein for regulating mitochondrial fission.Its activity is associated with the post-translational modification,mainly including phosphorylation,ubiquitination,sumoylation,and S-nitrosylation.During the cerebral ischemia,Drpl is activated and translocates from the cytoplasm to the mitochondrial outer membrane,mediates mitochondrial fission and eliminates damaged mitochondria.Drpl plays the important roles in the pathological processes of ischemic neuronal apoptosis,necrotic apoptosis,and mitophagy.Excessive mitochondria fission or accumulation of damaged mitochondria will aggravate neuronal injury.