| Nowdays cerebrovascular diseases still are the third cause for death in the whole world, therefore the study in this field has been an important aspect of medical research. Once stroke occurs, it often leads to neurologic deficit which seriously influence the quality of life and even threaten the life of patients. Although many protective treatment measures, such as Chinese medical science and western medicine, against brain ischemia damage have been found, few of them show satisfactory curative effect. Therefore, prevention measures are gradually emphasized in the treatment of brain ischemia. Recently, a lot of studies have focused on preconditioning measures of brain ischemia . Some anesthetics have been proved to have preconditioning effect on brain ischemia. However, whether desflurane preconditioning can induce brain ischemic tolerance has not been reported. In this study, we evaluated the effects of desflurane preconditioning of neuroprotection against middle cerebral artery occlusion injury in rat with diffusion -weighted MR imaging for the first time. The present study was designed to evaluate the following objectives in a rat middle cerebral artery occlusion (MCAO) model. (1) To investigate if desflurane preconditioning induces ischemic toleranceagainst neuronal injury produced by MCAO in rats.(2) To investigate if once short-duration desflurane preconditioning induces ischemic tolerance against brain injury produced by MCAO in rats.(3) To investigate the effects of DPCPX, an adenosine receptor antagonist, on the brain ischemic tolerance induced by preconditioning with once short-duration desflurane. Experiment 1:AIM To investigate if desflurane preconditioning induces delayed ischemic tolerance against neuronal damage produced by MCAO in rats. METHODS Thirty male Sprague-Dawley (SD) rats weighing 280-320g were randomly divided into three groups: control group (C), without pretreatment; desflurane preconditioning group (Des), inhalation of 5.7% desflurane mixing with 94% O2 lh per day for 5d;oxygen preconditioning group (Oi), inhalation of 94%O2 1h per day for 5d. Right MCAO (120min) was induced by a 3-0 nylon thread with round tip inserted cranially into right internal carotid artery. The neurologic deficit score (NDS) was evaluated 24h after reperfusion and the infarct volume was determined 24h after reperfusion. RESULTS The NDS of Des group was lower than other two groups (P<0.01). The infarct volume of C, O2 and Des group was (276.10+155.63) mm3, (253.84+174.39) mm3 and (59.56+30.37) mm3 respectively. The difference between Des group and C group was significant (P<0.01). CONCLUSION Desflurane pretreatment was able to induce delayed ischemic tolerance against neuronal injury produced by transient MCAO in rats. Experiment 2:AIM To investigate if once short-duration desflurane preconditioning induces acute ischemic tolerance against brain injury produced by MCAO in rats. Methods Thirty male SD rats weighing 280-320 g were randomized into threegroups: control group (C), without pretreatment; oxygen-inhaling group (O2), with inhaling 94% O2 1h; desflurane preconditioning group, inhalation of 5.7% desflurane mixing with 94% O2 1h, n=10, (Des). Each animal was then subjected to 2-hour MCAO by the intraluminal suture technique. The NDS were evaluated 24h after reperfusion and the infarct volume were measured with diffusion-weighted imaging (DWI) and TTC staining at 24 hours of reperfusion. Results Rectal temperature, PH, PaO2, PaCO2, blood pressure and blood glucose were controlled and not different among groups during preconditioning. The NDS of Des group was lower than those of other two groups at 24 hours of reperfusion. The infarct volume was smaller in Des group(TTC:323.44+50.12 mm3 ;DWI:281.48+35.16mm3) compared with O2 group (TTC:427.96+87.26 mm3 ;DWI:386.70+27.86 mm3) and control group (TTC:498+43.88 mm3;DWI: 402.53+28.14 mm3), but the infarct volume was no significant difference between O2 group and control group (P>0.05). Conclusions Once short-duration desflurane pretrea... |
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