The Study Of The Variance Of The Activity And Expression Of Myosin Light Chain Kinase In Artery Wall And Liver Of Atherosclerotic Rabbit

Objective: To study the effect of vitamin E on the activity and expression of mysin light chain kinase in the liver of atherosclerosis model rabbits. To analyze the variability of the expression of mysin light chain kinase in the artery of atherosclerotic model rabbits and analyze the variability of lactate dehydrogenase and creatine kinase in the serum of atherosclerotic rabbits. Methods: The rabbit model of atherosclerosis was established. The biochemical quotas such as blood lipid, AST, ALT, LDH, CK, BUN and Cre were assayed in the serum of atherosclerotic rabbits of each stage. The activity of MLCK of the rabbit liver was measured by the method of - 32P incorporated and its expression was detected by immunofluorescent. Western blot and immunohistochemical methods were used to analyse the expression of MLCK in the artery of atherosclerotic rabbits. Results: The atherosclerotic rabbits model was established successfully. The concentration of total cholesterol (CHO) and low density lipoprotein cholesterol ( LDL-ch ) in the blood of group ASa (feeding with cholesterol and lard for four weeks) and group ASb (feeding with cholesterol and lard for twelve weeks) increased markedly, and there was significantly statistical difference compared with the contrast group(P<0.05), whereas the activity of alanine aminotransferase(ALT) and aspartate aminotransferase (AST) and the concentration of blood urea nitrogen(BUN) and creatinine(Cre) is always the same (P>0.05) . In the group fed with cholesterol, lard and vitamin E for twelve weeks, the TG, CHO, HDL-ch, LDL-ch and VLDL-ch increased obviously and there is .significantly statistical difference compared with thecontrast group (P<0.05). The activities of lactate dehydrogenase (LDH) and creatine kinase (CK) increase along with the development of atherosclerosis. The activity of LDH in the blood of group ASa and group ASb increased by 2.2 times and 3.5 times respectively compared with that of contrast group; while the activity of CK increased by 2.4 times and 7.5 times respectively. After the rabbits being fed with cholesterol for four weeks and twelve weeks, the activity of MLCK in the liver increased markedly, and there is significantly statistical difference compared with the normal control respectively (P < 0.05). While the rabbits were fed with cholesterol and vitamin E for twelve weeks, the activity of MLCK did not change markedly, there is no statistical difference compared with the normal control (P > 0.05). The MLCK expression increased after the rabbits being fed with the feed of cholesterol for four weeks, and it increased more and more obviously after the rabbits being fed with the feed of cholesterol for twelve weeks. The expression of MLCK appears to be decreased when vitamin E was added into the cholesterol feed. After being fed with cholesterol and lard for four weeks or twelve weeks, the expression of MLCK in the artery of atherosclerotic rabbits increased markedly, whereas there was no obvious difference in the expression of MLCK in the artery of atherosclerotic rabbits being fed with cholesterol and lard and vitamin E for twelve weeks compared with that of control. Conclusions: The increase of the activities of LDH and CK in the serum of atherosclerotic rabbits may be well correlated with the development of atherosclerosis. The pathology of liver may be associated with the increase of the activity of MLCK. Vitamin E may be inhibiting the activity of MLCK and it may protect hepatocyte from injury. Our study suggests for the first time that increased expression of MLCK in the artery of atherosclerotic rabbits may be well correlated with the development of atherosclerosis. Vitamin E may play an important role in prevention of atherosclerosis by protecting endothelium and smooth muscle cell in arterial wall from destruction and by decreasing the expression of MLCK.