The Expression Of Myosin Light Chain Kinase In Endothelial Cell Is Regulated By The Melatonin Through The Pathway Of ERK/MAPK In Atherosclerosis Model Rabbit

Objective To study the possibility of the expression of myosin light chain kinase(MLCK) in endothelial cell is regulated by the melatonin through the pathway of ERK/MAPK in atherosclerosis model rabbit. Methods To establish the model rabbit of atherosclerosis(AS) and analyze the dynamic variability of the lipids and other related biochemistry quotas in the serum of model rabbits. The MLCK activity of artery tissue of model rabbits was measured by the method ofγ-32P-ATP incorporated and the endothelial permeability was detected by immunofluorescent. The expression of MLCK in the endothelial cell was detected by immunohistochemistry and western blot, meanwhile, the phosphorylation of ERK in the endothelial cell was also detected by western blot. The change of morphology of artery wall in modle rabbits was examined according to the HE stain. The human umbilical vein endothelial cells (HUVECs) were treated by ox-LDL to analyze the levels of transcription and translation of MLCK. Results The AS rabbit model was established successfully. After being fed with the high cholesterol(CHO) for 1,2,3,4 weeks,the triglyceride(TG), CHO, high-density lipoprotein(HDL) and low-density lipoprotein(LDL) increased obviously in the serum, there is significantly statistical difference compared with the normal control( P<0.05,P<0.01,P<0.05,P<0.01). After being fed with high CHO for 8 weeks, the TG, CHO, HDL and LDL increased little in the serum and no statistical difference is found compared with the model group of 4 weeks. While after being fed with high CHO for 12 weeks,the content of the TG, CHO and LDL degraded compared with the model group of 8 weeks. In group fed with high CHO and melatonin, the concentrations of the TG, CHO and LDL decreased compared with the model group which fed with high CHO. After feeding with high CHO for 1,2,3,4,8,12 weeks, the MLCK activity of artery tissue of model rabbits increased gradually,and there is significantly statistical difference when compared with normal control(P<0.05). The permeability of arterial intima, the expression of MLCK and the phosphorylation of ERK in the artery tissue were raised gradually after the rabbits were fed with high CHO for 1,2,3,4,8,12 weeks. At the same time,the HE staining indicated that there are a lot of foam cells products gradually. When melatonin(MLT) was added into the high CHO food,the activity of MLCK,the permeability of arterial wall,the expression of MLCK and the phosphorylation of ERK in artery tissue degraded all,the aortic tunica intima symptom seem to be reliefed. Conclutions With the development of AS, the changes of endarterium integrity may be related with the augmented activity of MLCK. The expression of MLCK and the phosphorylation of ERK present consistency in artery tissue of AS model rabbit. MLT may relief the pathological changes of plaque in the AS model rabbit through the pathway of ERK/MAPK to down regulation the activity of MLCK in endothelial cell.