| Objective:The effects of Sufentanil postconditioning on myocardial ischemia reperfusion injury(MI/R) as well as myocardial cell apoptosis in diabetic rats and its relationship with1-phosphatidlylinositol 3-kinase/protein-serine-threonine kinase(PI3K/Akt)pathway and AIFMethods:Healthy adult male Sprague Dawley(SD) rats weighing 260 ~ 300 g, were in the preparation of diabetic rats model by intraperitoneal injection of streptozotocin65mg/kg.Twenty-four rats which diabetes mellitus model was successfully established were randomly divided into four group(n=6 each): diabetic mellitus sham operation group(group DM-S); diabetic mellitus ischemia-reperfusion group(group DM-IR); diabetic mellitus sufentanil postconditioning group(group DM-SP)and diabetic mellitus sufentanil postconditioning+Wortmannin group(group DM-SP+W). Another 24 nondiabetic mellitus rats were also randomly divided into 4 group(n=6 each): nondiabetic mellitus sham operation group(group NDM-S), nondiabetic mellitus ischemia-reperfusion group(group NDM-IR); nondiabetic mellitus sufentanil postconditioning group(group NDM-SP) and nondiabetic mellitus sufentanil postconditioning+Wortmannin group(group NDM-SP+W).Myocardial I/R was induced by 30 minutes occlusion of left anterior descending branch of coronary artery followed by 120 minutes reperfusion. Group S receieved no occlusion or reperfusion. Group SP was induced by iv injection of sufentanil 1.0 μg/kg at 5 min before reperfusion, while group SP+W received wortmannin 15ug/kg before sufentanil injection.Abdominal aortic blood samples were collected at 120 min of reperfusion for measurement of the serum creatine kinase isoenzyme-MB(CK-MB) concentration; The animals were then sacrificed for determination of myocardial infarct size(IS) and area at risk(AAR),IS/AAR ratio was calculated; Apoptosis index(AI) was calculated by TUNEL; The expression of Akt and phosphorylated Akt(p-Akt)was determined by Western blotting.Separate the mitochondria and cytoplasm for the determination of Apoptosis-inducing factor(AIF) by Western blotting.Results:1. CK-MB concentration In diabetic and nondiabetic rats, compared with group S, serum CK-MB concentration inseased, in group IR, SP and SP+W(P<0.05). In nondiabetic rats, serum CK-MB concentration of group NDM-SP was lower than group NDM-IR(P<0.05), Compared with group NDM-SP, serum CK-MB concentration inseased in group NDM-SP+W(P<0.05).But in diabetic rats, there was no statistically significant difference of the above indicator between corresponding groups(P> 0.05). The CK-MB concentration of group DM-SP were significantly elevated than group NDM-SP(P<0.05).2. IS/AAR ratio Compared to their corresponding S group, all groups had a higher IS/AAR ratio(P<0.05). Compared with NDM-IR group, the IS/ARR ratio is significantly lower in NDM-SP group(P<0.05); The IS/ARR ratio was higher in NDM-SP+W group than NDM-SP group(P<0.05). However, no same significant difference was found between corresponding group of diabetic rats. Compared with NDM-SP group(P> 0.05), IS/ARR ratio was significantly decreased in DM-SP group(P<0.05).3. Akt and p Akt western blot analysis The total Akt levels did not vary between study groups(P> 0.05). Compared to their corresponding S group, all groups had a higher p Akt protein levels(P< 0.05). NDM-SP group had higher p Akt protein levels, compared with the NDM-IR group(P<0.05). p Akt protein levels was higher in DM-SP than NDM-SP+W group(P<0.05). However, no samesignificant difference was found between corresponding group of diabetic rats. Compared with NDM-SP group(P > 0.05), p Akt protein levels was significantly increased in DM-SP group(P<0.05).4. The percentage of AI Compared to their corresponding S group, all groups had a higher AI(P<0.05).Compared with NDM-IR group, the AI ratio is significantly lower in NDM-SP group(P<0.05); The AI ratio was higher in NDM-SP+W group than NDM-SP group(P<0.05). However, no same significant difference was found between corresponding group of diabetic rats. Compared with NDM-SP group(P>0.05), AI was significantly decreased in DM-SP group(P<0.05).5. AIF western blot analysis Compared to their corresponding S group, the serum AIF concentration from Mitochondria to Cytoplasm was higher other groups(P<0.05). Compared with NDM-IR group, thethe serum AIF concentration from Mitochondria to Cytoplasm was significantly lower in NDM-SP group(P<0.05); The the serum AIF concentration from Mitochondria to Cytoplasm was higher in NDM-SP+W group than NDM-SP group(P<0.05). However, no same significant difference was found between corresponding group of diabetic rats.Compared with NDM-SP group(P>0.05),the serum AIF concentration from Mitochondria to Cytoplasm was significantly decreased in DM-SP group(P<0.05).Conclusion:1. Sufentanil postconditioning can protect myocardium against I/R injury in nondiabetic rat heart.2. Diabetes mellitus factor can negate the effect of sufentanil postconditioning protection against myocardial ischemia-reperfusion injury, which may be associated with the abnormal pathway of PI3K/Akt indiabetes mellitus rats. |
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