Effect Of Simvastatin On P-selectin Expression In Rats Of Type 1 Diabetes Myocardial Disease

Objective:To investigate the effect of Simvastatin on p-selectin expression in rats of type 1 diabetes myocardial disease.Methods::54 male Wistar rats weighing 190-230g were divided randomly into three groups, namely normal control (NC, n=18), diabetes mellitus group (DM, n=18), and Simvastatin group (S, n=18). After fasting for 12 hours, STZ with a concentration of 55mg/kg was dissolved in the Citric Acid balanced solution and was injected into the rats of group DM and group S to establish the models of diabetes rats. The rats of the group NC was injected with the same amount of Citric Acid balanced solution. The models would be successfully established if concentration of the random blood sugar≥16.7mmol/L three times consecutively 72 hours later. One week after the establishment of the models, the S group received the intragastric administration with the suspension of Simvastatin and physiological saline of 10mg.kg-1.d-1, while the other groups with the same amount of physiological saline. At weeks of 4,8 and 12,6 rats were taken from each group and were weighed. We collected the blood from the cut nail and tested the blood sugar; we collected the blood from the caval vein after anesthetizing the rats, abstracted the blood serum and tested the amounts of the Insulin and P-selectin; at the end of the experiment, we took the heart away from the rats, abscise the envelope, blot it and weighed it. After that we tested the heart weight index (heart mg/weight g), and cut cardiac muscles from the same site of left cardiac ventricle. Part of the muscles was froze at the temperature of minus70℃. We determined the P-selectin mRNA by RT-PCR. The other part of cardiac muscles was fixed by neutral formaldehyde with a concentration of 10%, dehydrated, wraped with paraffin, made pathologic slices and dyed with HE. And then through optical microscope we observed the morphological change of the cardiac tissue and measured the area of the cardiac cells. At last we tested the concentration of P-selectin by immunohistochemistry manner.Results:1.72 hours after the injection of STZ, the fasting glucose of rats in DM group and S group was significantly higher than normal, and compared with the NC group, the differences were significant(P<0.05); The concentration of insulin of DM group and S group was lower than that of NC group, and the differences was significant(P<0.05).2. Compared with the NC group, the heart weight index and the area of the cardiac cells of the DM group and S group increased, and the differences were significant(P<0.05); compared with the DM group, the heart weight index and the area of the cardiac cells of S group decreased, and the differences were significant(P<0.05)3. Compared with the NC group, the serum concentration of P-selectin of DM and S group was higher, and the differences were significant (P<0.01); compared with DM group, the serum concentration of P-selectin of S group was lower, and the differences were significant (P<0.01).4. Through the observation by optical microscope of the HE dyeing slices, we found that collagen fibers of cardiac muscle of NC group were slim, equally distributed, and orderly, without pathological changes. the cardiac muscle cells of DM group were swollen and loose, the collagen fibers of cardiac muscle were disorganized 4 weeks later; the changes mentioned above were more serious and accompanied with inflammatory cell infiltrate, collagen fibers fragmented, a great amount of collagen fibers appeared in and among the cardiac muscle fibers 8 weeks later; the pathological changes became more serious, fragmented the collagen fibers and fibrous degeneration became more significant 12 weeks later。these changes of Simvastatin group were gradually reduced with the intervention time going,5. Compared with NC group, the result of immunohistochemistry tests showed the P-selectin expressions in rats of DM group and S group were much higher, the differences were significant (P<0.01); compared with DM group, the P-selectin expression in rats of S group was lower, the differences were significant (P<0.01)6. Copmpared with NC group, the result of RT-PCR tests showed that the mRNA for P-selectin expression in cardiac tissue of DM group and S group increased significantly, the differences were significant(P<0.05); compared with DM group, that in S group decreased,and the difference were significant(P<0.05).7. Through the scatterplot of P-selectin expression in cardiac tissue of rats with DM, we found that the heart weight index and the area of the cardiac cells increased with the expression of P-selectin. Pearson correlation analysis showed P-selectin expression in cardiac tissue of rats with DM was in positive correlation with the heart weight index(r1=0.895,P1<0.01) and the area of the cardiac cells(r2=0.863,P2<0.01).Conclusion:The rising of the P-selectin in the cardiac muscle tissues is closely related to the occurrence of the diabetic cardiomyopathy. P-selectin plays an important role in the development of diabetic cardiomyopathy. Simvastatin plays a protection role in the development of diabetic cardiomyopathy by decreasing the expression of P-selectin.