摘要
目的观察褪黑素(MLT)对实验性动脉粥样硬化兔心脏的保护作用及其可能的分子机制。方法普通级纯种新西兰大耳白兔随机分为3组,正常组:饲喂普通饲料;模型组:饲喂高脂饲料(普通饲料+1%胆固醇+5%猪油);褪黑素组:饲喂高脂饲料的同时MLT灌胃10 mg/(kg·d)治疗。纯种大耳白兔适应性饲养一周后,采用高脂饮食诱导造模,同时给予褪黑素药物治疗。于12周后处死进行采血,检测血清中血脂等指标。取动脉进行油红染色,检测脂质斑块形成情况;取心脏组织,包埋后HE染色观察心肌组织的形态变化;Masson染色检测心肌组织中胶原纤维的变化;Western blot法检测p38/丝裂原活化蛋白激酶(MAPK)通路相关蛋白及肌球蛋白轻链激酶(MLCK)、肌球蛋白轻链(MLC)、肌球蛋白轻链磷酸化(p-MLC)的表达水平。结果动脉油红染色结果显示模型组出现大量脂质斑块,证明造模成功。血脂结果显示模型组总胆固醇(TCH)、三酰甘油(TG)浓度明显上升,而褪黑素组相对模型组下降。油红染色HE染色结果显示MLT能改善心肌组织形态的紊乱情况,Masson染色结果显示MLT能缓解心肌组织胶原纤维的堆积。Western blot结果显示MLT能下调p38的磷酸化水平以及MLCK蛋白的表达水平,以及下调MLC的磷酸化表达水平(P<0.05)。结论 MLT可能通过降低MAPK通路中相关蛋白p38的磷酸化调控MLCK蛋白的表达,从而降低MLC的磷酸化水平对动脉粥样硬化兔心肌组织起到保护作用。
Objective To explore the effects of melatonin on myocardial tissue of experimental atherosclerosis rabbits and the possible mechanism. Methods New Zealand white rabbits were randomly divided into 3 groups： the normal group were fed with standard diet; high-fat diet model group were fed with high-fat diet（ standard diet supplemented with 1% cholesterol ＋ 5% lard）; MLT group were fed with high-fat diet and MLT [10 mg/（ kg·d）].Rabbits were adaptability raised after 1 week,high fat diet were used to induce model,melatonin was given by medical treatment. After 12 weeks,rabbits were sacrificed to get blood,detection in serum lipid indexes. Artery of lipid plaque was observed by oil red staining. Haematoxylin-eosin（ HE） staining was used to detect myocardial tissue morphological changes. Masson staining was used to detect myocardial tissue changes of collagen fibers. Mitogen-activated protein kinase（ MAPK） pathways related proteins p38 and myosin light chain kinase（ MLCK）,myosin light chain（ MLC）,phophorylation,myosin light chain（ p-MLC） were detected by Western blot. Results Arterial oil red staining showed a large number of lipid plaques in the model group,demonstrating successful modeling. Compared with the normal group,concentration of total cholesterol（ TCH） and triglyceride（ TG） in model group increased significantly. HE,Masson staining showed that MLT can improve myocardial disorder in the form of organization situation and alleviate myocardial tissue accumulation of collagen fibers. Western blot showed that MLT can reduce p38 degree of phosphorylation,MLCK protein expression level,and decrease the phosphorylation of the degree of MLC（ P〈0. 05）. Conclusion MLT may regulate the expression of MLCK protein by decreasing the phosphorylation of MAPK/p38 signaling pathway related proteins p38,thereby reducing the phosphorylation level of MLC to protect the myocardium of atherosclerotic rabbits.
出处
《安徽医科大学学报》
CAS
北大核心
2017年第12期1747-1751,共5页
Acta Universitatis Medicinalis Anhui
基金
国家自然科学基金(编号:81570419)
安徽省高校省级自然科学研究项目(编号:KJ2013Z127)
