丙泊酚对大鼠局脑缺血后线粒体膜电位及ROS生成的影响

Objective To observe the effects of propofol on membrane potential and reactive oxygen species in mitochondria isolated from brain subregions during focal cerebral ischemia in rat. Methods Eighteen Wistar rats (weight 250~300g) were recruited after 2 h of focal ischemia. The focal cerebral ischemia was induced by an intraluminal middle cerebral artery occlusion (MCAO) technique. The cortical focal tissue and the same position from the contralateral hemisphere were quickly removed, and then the mitochondria were isolated by the procedures that combine differential centrifugation and discontinuous Percoll density gradient centrifugation. As the mitochondria were detected by flow cytometric, the low Purity (<95%) of the preparations were discard. The preparations were divided into 3 groups at random(n=6), which were ischemic groups (A,B,C) and contralateral group (Ⅰ,Ⅱ,Ⅲ). Mitochondria (30ug/0.3ml) were incubated in reaction buffer for 2 min and then were disposed differently. The extracted mitochondria of group A and group Ⅰ were not disposed; The extracted mitochondria of group B and group Ⅱ was incubated by TMRM for 10 min at 37℃ or incubated by H2DCFDA for 30 min at 37℃; The extracted mitochondria of group C and group Ⅲ was incubated by propofol for 2 min at 37℃ and then incubated by TMRM for 10 min at 37℃ or incubated by H2DCFDA for 30 min at 37℃.Flow cytometric detected the signal intensity of TMRM and DCF. TMRM for measuring mitochondrial membrane potential and DCF for measuring mitochondrial reactive oxygen species was evaluated by signal intensity. Results Purity of mitochondria in group was more than 98% ( P<0.05); Mitochondria isolated from the contralateral hemisphere showed high membrane potential and lower production of reactive oxygen species( P<0.05); propofol has been demonstrated to increase membrane potential of mitochondria isolated from focal cerebral ischemia ,and inhibit reactive oxygen species generation of mitochondria isolated from focal cerebral ischemia( P<0.05); propofol has been demonstrated to increase membrane potential of mitochondria isolated from contralateral hemisphere, while it has no effect on reactive oxygen species generation of mitochondria isolated from contralateral hemisphere( P<0.05). Conclusion Propofol shows better preservation of mitochondrial function after focal cerebral ischemia, indicated by inhibition of reactive oxygen species generation and increasing membrane potential of mitochondria. This may be involved in the mechanism of the brain protection of propofol.