Protective Effects Of Lycopene On Hypoxia/Reoxygenation Injury In Rat Cardiomyocytes And It's Mechanism

BackgroundChina Health Yearbook 2000 published cardiovascular (including cerebrovascular) disease mortality, which were 236.08/10 million people in the city, accounting for 38.45%; 186.56/10 million in rural, accounting for 30.77%, both on the first place of total mortality; about 300 Million people die of cardiovascular disease per year; coronary heart disease has become hospitalized due to cardiovascular disease in patients with the most common species. Acute myocardial infarction is the major pathophysiological basis of complete or incomplete thrombosis artery blockage, and then cause myocardial injury caused by ischemia, after aggressive treatment of coronary reperfusion after blocking, the blood flow re-create the secondary reperfusion injury. Present study suggests that oxidative stress and leukocyte infiltration are the main reasons to ischemia / reperfusion injury.Lycopene is found a very popular natural anti-oxidants in recent years, studies show that lycopene is the strongest antioxidant in the natural class of carotene, the antioxidant activity of lycopene is far better thanβ-carotene and vitamin E, it can significantly block the body's lipid peroxidation, increased the activity of various antioxidant enzymes, which enhance the body's antioxidant capacity to maintain normal cell metabolism.Whether the lycopene has the protective effect on the myocardial hypoxia/reoxygenation injury caused by the factors such as the oxidative stress or leukocyte infiltration has not been reported. Therefore, this study will explore the effects of lycopene on myocardial hypoxia/reoxygenation injury and its mechanisms.Objective:1 Identify the protective effects of lycopene on myocardial hypoxia/reoxygenation injury in rats.2. Preliminary explore the mechanisms of lycopene's protective effects on on myocardial hypoxia/reoxygenation injury.Methods:ExperimentⅠ:Identify the protective effects of lycopene on myocardial hypoxia/reoxygenation injury in rats. The H/R injury model of primary cultured neonatal rat cardiomyocytes was established. The cultured cardiomyocytes were divided into eight groups: control group, H/R group, H/R + lycopene (1, 2, 4, 8, 16, 32μmol / L) dose groups. The cells were observed by H/R injury, intracellular aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD) activity and malondialdehyde (MDA) content changes. ExperimentⅡ: Preliminary explore the mechanisms of lycopene's protective effects on on myocardial hypoxia/reoxygenation injury. According to the data of each group in the ExperimentⅠ, choose the most significant protective effect of use-dose(16μmol/L) as the test dose for the experimentⅡ. The experimentⅡ: still uses the original establishment of cultured myocardial cells during hypoxia/reoxygenation injury model, which were divided into three groups: control group, H/R group, H/R_+lycopene(16μmol/L) group. MTT in each group was analyzed for apoptosis, Western-Blot detected of TRL 4 and NF-κB expression.Results:ExperimentⅠ: After 30 min hypoxia and 2 h reoxygenation, The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R group were 580.6±109.63,523.57±95.22,314.37±17.38,29.44±8.47,24.66±9.44;The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(1μmol/L) group were 512.37±68.46,436.42±107.43,294.85±18.03,29.44±8.47,25.83±5.32, compared with H/R group, all the indexes were not statistically different.The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(2μmol/L) group were 463.92±90.72,440.57±112.35,271.26±19.38,33.79±8.48,24.23±4.91, compared with H/R group, the AST's release is lower(P﹤0.01).The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(4μmol/L) group were 408.05±103.38,387.46±101.95,268.44±23.05,34.58±7.02,21.39±5.12, compared with H/R group, all the indexes were lower. (P﹤0.05)The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(8μmol/L) group were 375.29±88.58,329.59±108.33,253.61±25.01,36.62±7.22,18.94±4.77, compared with H/R group, all the indexes were lower. (P﹤0.01).The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(16μmol/L) group were 306.50±100.16,307.41±90.98,241.76±22.11,41.93±8.67,15.96±3.17, compared with H/R group, all the indexes were lower. (P﹤0.01).The LDH, CK, AST's release (U/L), SOD concentration (U/L) and the amount of MDA formation (nmol/ml) in myocardial cells in H/R_+lycopene(32μmol/L) group were 523.63±110.17,506.83±113.42,298.58±23.89,32.11±7.87,25.04±4.06, compared with H/R group, all the indexes were not statistically different.ExperimentⅡ: After 30 min hypoxia and 2 h reoxygenation, compared with H/R group, the MTT results of apoptosis showed the cardiomyocyte survival rate had increased 37.6% (P﹤0.05), but it was lower than that in the normal control group(P< 0.05). The expression of TLR-4 protein and NF-κB protein in lycopene group was significantly lower than that in the H/R group but it was higher than that in the normal control group.(P< 0.05). Conclusion:1. Lycopene groups(2, 4, ,8, 16μmol/L) decreased the activities of AST, CK, LDH and the production of MDA, and significantly increased the activity of SOD.2. Lycopene has anti-hypoxia/reoxygenation injury, protection of myocardial cells, which may be by inhibiting pathways to TRL 4.