Protective effect of naloxone on mitochondrial membranal potential of hypoxic myocardial cells and apoptosis
- VernacularTitle:缺氧心肌细胞线粒体膜电位及细胞凋亡与纳洛酮的保护效应
- Author:
Yuhong QIN
;
Tiande LI
;
Hong SHEN
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2007;11(8):1573-1576
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND: Studies confirm that ischemia/reperfusion (I/R) injury can induce myocardial apoptosis. The loss of mitochondrial membrane potential (MMP) after reperfusion is the inevitable pathway of apoptosis. Protection of MMP may reduce apoptosis.OBJECTIVE: To observe the effect of naloxone on MMP of hypoxic myocardial cells and apoptosis in neonatal rats, and investigate the protective effect of naloxone on hypoxic myocardial cells.DESIGN: Observation and controlled trial.SETTING: Department of Cardiology, the General Hospital of Chinese PLA.MATERIALS: Detection of apoptosis of myocardial cells was carried out in the Laboratory of Pathophysiology, General Hospital of Chinese PLA in December 2004. Ten neonatal rats were used, and detection of MMP of myocardial cells was carried out in the same laboratory in March 2006 and 20 rats were used. All the involved rats were provided by the Animal Center of the General Hospital of Chinese PLA on the day of birth, were involved in this trial. Reagents: Naloxone hydrochloride injection (0.4 g/L, Beijing Sihuan Pharmaceutical Factory, Batch No. 0206272); the lowest and essential medium (Dulbecco, DEME,GIBCO company); phosphate buffer solution and fetal bovine serum (PBS and FBS, SIGMA Company).METHODS: The neonate rats were cut open along the median line of chest bone after local sterilization with iodine tincture on the day of birth. 1/3 ventricular myocardium before cardiac apex was harvested. On the 4th day of the culture,culture flasks of cells in good growth status ( ＞ 106 cells/bottle) were selected and divided into 3 groups: control group (normal culture, n =3 bottles), hypoxia group (hypoxia/reoxygenation, n =15 bottles) and naloxone group (hypoxia/reoxygenation, and treated by naloxone, n =15 bottles). Three time points were set in hypoxia group and naloxone group according to different time of hypoxia and reoxygenation: hypoxia 2 hours/reoxygenation 0 hour; hypoxia 2 hours/reoxygenation 2 hours; hypoxia 2 hours/reoxygenation 4 hours, 5 bottles at each time point. In the hypoxia group, DEME medium, which was pre-filled with 0.95 volume fraction of N2 and 0.05 volume fraction of CO2, containing 0.01 volume fraction of FBS, was used and 0.95 volume fraction of N2 and 0.05 volume fraction of CO2 was also filled to replace the air in the culture flasks. The culture flasks were enveloped for incubation at 37 ℃. The cells in the hypoxia group were incubated at normal condition (0.95 volume fraction of air and 0.05 volume fraction of CO2) at set time. In the naxolone group, hypoxia/reoxygenation treatment was the same as above, and naloxone hydrochloride was added at the sametime and the final concentration of naloxone in culture flasks was 5 μmol/L (The volume for naloxone ≤ 0.5% of the total medium). In the control group, hypoxia/reoxygenation and naloxone treatment were not given, but the same volume of normal saline was added, and this time served as time point of hypoxia 0 hour/reoxygenation 0 hour. After intervention,myocardial MMP changes and apoptosis were detected with fluorescent staining-flow cytometer at different time after hypoxia/reoxygenation.MAIN OUTCOME MEASURES: ① MMP changes of hypoxia group and naloxone group at different time points; ② Comparison of survival, apoptosis and necrosis of cells at hypoxia 2 hours/reoxygenation 4 hours in each group.RESULTS: ① After hypoxia, MMPs of the cells in hypoxia group and naloxone group were decreased. MMP of the cells in the naloxone group was higher than that in the hypoxia group at each time point (P ＜ 0.01). The great amplitude of decrease of MMP occurred in hypoxia period, but not in reoxygenation period. ② At hypoxia 2 hours/reoxygenation 4 hours, the apoptotic and necrotic rates in the hypoxia group were significantly higher than those in the naloxone group [(9.88±0.98)% vs. (2.41±0.52)%; (5.10±0.29)% vs. (3.56±0.56)%, both P ＜ 0.01]. The apoptotic rate was significantly higher than the necrotic rate in the hypoxia group (P ＜ 0.05).CONCLUSION: Early application of naloxone can significantly alleviate and postpone the decrease of myocardial MMP after I/R, and reduce apoptosis and necrosis.
