| Dipfluzine (Dip), a novel calcium antagonist ofdiphenylpiperazines with similar structure of flunarizine, wassynthesized by Hebei Medical University. It had been testedthat Dip could prevent calcium flowing into the cytoplasm andmaintain the homestasis of calcium. And it could reach higherconcentration in the brain tissue and increase brain blood flow.Moreover, Dip could improve amnesia and protect mice againstthe acute cerebral hypoxia. At present, more and morethrombolysis drugs are applied on the clinical, which has bringnew hope to the patients with cerebral infarction. But at thesame time the new cerebral ischemia-reperfusion injuryproblems occur. So, the present study is to observe whether Dippossesses the protective effects on the brain injury in model ofthe global cerebral ischemia-reperfusion induced by the fourvessel occlusion (4-VO) through measuring the content ofmitochondria calcium, and to shed light on the protective effectsof Dip on the global cerebral ischemia-reperfusion injury in rats.And we also want to further study the protective effects of Dipon mitochondria injury induced by exogenous Ca2+ viameasuring mitochondria viability (MTT), mitochondriapermeability transition (MPT) and mitochondria membrane 7potential (△?). The experiments procedures are as follows: 1 Comparison of the models of mitochondrial injury inglobal cerebral ischemia-reperfusion for different time. Objective: To evaluate the best model by measuring thecontent of mitochondria calcium and some biochemistry indexesafter global cerebral ischemia-reperfusion in different time. Methods: The model of global cerebral ischemia-reperfusion was made by using Pusinellis 4-VO method.Twenty-four SD rats (weighing 250-300g, male, healthy) wererandomly divided into 4 groups :(1) sham operation controlgroup; (2) reperfusion 1 hour after 15 min global cerebralischemia group; (3) reperfusion 2 hour after 15 min globalcerebral ischemia group; (4) reperfusion 4 hour after 15 minglobal cerebral ischemia group. Rats in sham operation controlgroup only underwent an operating procedure, and were killed24 hours after reperfusion. Rats in test groups were occluded thecommon carotid arteries and vertebral arteries and killed afterreperfusion. Cerebellum and olfactory bulb were removed, theother parts were used to measure the content of mitochondriacalcium, the activity of Ca2+-ATPase and SDH. The proteincontent of mitochondria was determined by Coomassivetechnique. Results: The average content of mitochondrial calcium insham operation control group was 310±35nmol/L. Afterreperfusion 1h, 2h and 4h, the content of mitochondria calciumincreased remarkedly, which reached to 862±75nmol/L, 81224±113nmol/L, 1735±142nmol/L respectively. So, Thecontent of mitochondria calcium in the model groups was higherthan that of the sham operation control group (p<0.01).Moreover, from the biochemical indexes, the OD660 value thatrepresented the activity of Ca2+-ATPase was10.34±0.61U/mgpro in sham operation control group, while theOD660 values were 8.53±0.28U/mgpro, 7.87±0.53U/mgpro, and7.00±0.67U/mgpro in the reperfusion 1h, 2h, and 4h groupsrespectively. And the OD600 value that represented the activity ofSDH was 5.8±0.6U/mgpro in sham operation control group, inthe ischemia-reperfusion groups above the OD600 values weredecreased by 4.8±0.5U/mgpro, 3.9±0.6U/mgpro, and3.4±0.7U/mgpro respectively. Conclusion: The model of reperfusion 2 hours waschoosed as the best model to observe the effects of drugs on themitochondrial injury.
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