OBJECTIVETo explore the mitochondrial toxicities induced by zidovudine (AZT) and adefovir dipivoxil (ADV) antiviral drugs using a rat model system.

METHODSTwelve healthy Sprague-Dawley rats were randomly divided into three equal groups and treated by oral gavage with zidovudine (125 mg/kg/day), adefovir (40 mg/kg/day), or saline (equal volume) for 28 days. The rats' body weights were measured once a week, and blood was collected every two weeks for blood and biochemical tests. All animals were sacrificed at the end of treatment, and liver, kidney, skeletal muscle, and cardiac muscle were collected by necropsy. Mitochondria were isolated from the respective tissue samples, and the activities of respiratory chain complexes were measured. DNA was purified from each sample and the mitochondrial DNA (mtDNA) content was monitored by quantitative real time PCR. Mitochondrial morphology was analyzed under electron microscope.

RESULTSNo significant adverse effects, including body weight loss, abnormal blood or biochemistry, were observed in rats treated with AZT or ADV. The activities of mitochondrial cytochrome c oxidase in liver and cardiac muscle were slightly decreased in rats treated with AZT (liver: 9.44+/-3.09 vs. 17.8+/-12.38, P?=?0.21; cardiac muscle: 32.74+/-5.52 vs. 24.74+/-20.59, P?=?0.28; kidney: 4.42+/-1.53 vs. 14.45+/-13.75, P?=?0.18; skeletal muscle: 33.75+/-8.74 vs. 40.04+/-2.49, P?=?0.45). The mtDNA content was significantly decreased in cardiac muscle of AZT-treated rats (cardiac muscle: 0.15+/-0.13 vs. 0.32+/-0.42, P?=?0.85). The morphology of mitochondria in liver, kidney, skeletal muscle, and cardiac muscle was significantly altered in the AZT-treated rats and included disappearance of the outer membrane, severely damaged structure, and swollen or completely absent cristae. No obvious effects were noted in the ADV- or saline-treated rats.

CONCLUSIONSignificant adverse effects related to mitochondrial toxicity were observed in rats treated with AZT. The slightly decreased mtDNA content in ADV-treated rats may suggest that this antiviral drug can also cause mitochondrial toxic effects.

Adenine ; adverse effects ; analogs & derivatives ; Animals ; DNA, Mitochondrial ; drug effects ; Electron Transport Complex IV ; metabolism ; Female ; Kidney ; enzymology ; Liver ; enzymology ; Mitochondria ; drug effects ; metabolism ; Mitochondria, Heart ; drug effects ; Mitochondria, Liver ; drug effects ; Mitochondria, Muscle ; drug effects ; Muscle, Skeletal ; enzymology ; Myocardium ; enzymology ; Organophosphonates ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Zidovudine ; adverse effects

AIMTo study the effect of ligustrazine (LGT) and L-arginine(L-Arg)on function of mitochondria in myocardium after myocardial ischemia/reperfusion injury (MI/RI).

METHODS50 rabbits were randomly divided into five groups (n=10): Control group(A), MI/R group(B), MI/R + LGT group (C), MI/R+ L-Arg group (D), MI/R+ LGT + L-Arg group (E). The mitochondrial respiratory function, Ca2+ concentration ([Ca2+]m), malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were deter mined. Meanwhile, the contents of ATP and EC in the myocardial tissue were measured, respectively.

RESULTSIt was found that mitochondrial respiratory control rate (RCR), state 3 (ST3), SOD in C, D, E group were higher than those of B group, state 4 (ST4), [Ca2+]m, MDA were lower than those of B group, ATP and EC levels of myocardial tissue were higher than those in B group; and there were not significant differences between E and A group of above.

CONCLUSIONLGT and IL-Arg can improve function of mitochondria in myocardium after ischemia/reperfusion injury of myocardium in rabbits by decreasing oxygen free radical level and Ca" overload in the mitochondria.

Animals ; Arginine ; pharmacology ; Calcium ; metabolism ; Malondialdehyde ; analysis ; Mitochondria, Heart ; drug effects ; metabolism ; Myocardial Reperfusion Injury ; metabolism ; physiopathology ; Pyrazines ; pharmacology ; Rabbits ; Superoxide Dismutase ; metabolism

OBJECTIVETo investigate the effect of exogenous carnitine on function of respiratory chain and antioxidant capacity in mitochondria of myocardium in rats.

METHODSForty male Wistar rats were randomized to 4 groups (n = 10): static control (C), supplementation of carnitine (LC), exercise-training (T) and training with supplementation of carnitine (TLC). LC and TLC animals were perfused carnitine by the dose of 300 mg/kg bw x d. T and TLC animals were forced to performed 6-week treadmill training. Heart were prepared immediately after exhaustive running. Myocardium mitochondria was extracted by differential centrifugation. Spectrophotometric analysis was used to evaluate activities of respiratory chain complex (C) I -IV and superoxide dismutase (SOD), malondialdehyde (MDA) level in myocardium mitochondria.

RESULTSTo compare with C group, C I and C IV activity in LC, T and TLC group were increased significantly (P < 0.05, P < 0.01), CII and C III activity in T and TLC group were increased significantly (P < 0.05, P < 0.01); to compare with LC group, C I - IV activity in TLC group were increased significantly (P < 0.05, P < 0.01); to compare with T group, CI and C IV activity in TLC group increased significantly (P < 0.05). To compare with C group, SOD activity increased remarkably, MDA was remarkably lower (P < 0.05, P < 0.01) in LC, T and TLC group; To compare with LC and T group, SOD activity increased remarkably, MDA was remarkably lower (P < 0.05) in TLC group.

CONCLUSIONCarnitine and training could improve function of respiratory chain and increased antioxidant capacity in myocardium mitochondria, there was better function of cooperation between carnitine and training.

Animals ; Antioxidants ; metabolism ; Carnitine ; pharmacology ; Electron Transport ; Male ; Malondialdehyde ; metabolism ; Mitochondria, Heart ; drug effects ; metabolism ; physiology ; Physical Conditioning, Animal ; physiology ; Rats ; Rats, Wistar ; Superoxide Dismutase ; metabolism

OBJECTIVE: To observe whether HSP70 could protect against H2O2-induced apoptosis in C2C12 myogenic cells by inhibiting Smac release from the mitochondria. METHODS: HSP70 gene and full length Smac gene was transiently transfected in C2C12 myogenic cells by lipofectamine and the protein levels of HSP70 and Smac were analysed by Western blotting. Hoechst 33 258 staining was used to examine cell morphological changes and to calculate percentage of apoptotic nuclei. DNA ladder pattern on agarose gel electrophoresis was used to observe the DNA fragmentation. Activities of caspase-3 and caspase-9 were assayed with Western blotting. The release of Smac from the mitochondria to the cytoplasm was observed by immunofluorescence. RESULTS: H2O2 ( 0.5 mmol/L ) activated caspase-3, caspase-9 8 h after the treatment and specific morphological changes of apoptosis 12 h after the treatment, and overexpression of Smac significantly promoted H2O2-induced activation of caspase-3, caspase-9 and apoptosis in C2C12 myogenic cells. HSP70 overexpression significantly inhibited H2O2-induced and Smac-promoted apoptosis, as shown by no specific DNA ladder pattern in agarose gel electrophoresis, decrease of percentage of apoptotic nuclei, and marked inactivation of caspase-3 and caspase-9. HSP70 could inhibit the release of Smac from the mitochondria to the cytoplasm 2 h after the treatment by H2O2. CONCLUSION HSP70 inhibits Smac release from the mitochondria and protects against H2O2-induced apoptosis in C2C12 myogenic cells.
Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; Cells, Cultured ; HSP70 Heat-Shock Proteins ; pharmacology ; Humans ; Hydrogen Peroxide ; Intracellular Signaling Peptides and Proteins ; metabolism ; Mitochondria, Heart ; drug effects ; metabolism ; Mitochondrial Proteins ; antagonists & inhibitors ; metabolism ; Myoblasts ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism

OBJECTIVETo investigate the influence of pinacidil preconditioning on the protection of the structure and respiratory function of injured myocardial mitochondria in scalded rats.

METHODSSeventy-five healthy Wistar rats, weighed 250 approximately 300 g, were randomly divided into three groups: i.e. control (n = 9, with intraperitoneal injection of 50 microg/kg isotonic saline), scald (n = 33, with 30% TBSA full thickness scald) and pre-conditioning (n = 33, with same extent of scald injury after intraperitoneal injection of 50 microg/kg pinacidil) groups. Mitochondrial ultrastructure was observed by transmission electron microscope. The mitochondrial respiratory function, the MDA content and the superoxide anion level were determined with corresponding methods.

RESULTSThe degree of injury to rat myocardial mitochondria in pre-conditioning group was less intensive than that in scald group (P < 0.05 or 0.01). The respiratory control rate in pre-conditioning group was obviously higher than that in scald group (P < 0.05), and the contents of MDA and superoxide anion in pre-conditioning group were markedly lower than those in scald group (P < 0.05 or 0.01), as evidenced by their contents at 3 post scalding hours (0.60 +/- 0.09 micromol/g and 0.127 +/- 0.020) were obviously lower than those in scald group (0.83 +/- 0.07 micromol/g and 0.169 +/- 0.015) (P < 0.01).

CONCLUSIONPinacidil preconditioning was beneficial in the protection of myocardial mitochondria in scalded rats, and it might be related to the pre-opening of potassium channel which was sensitive to mitochondrial ATP.

Animals ; Burns ; drug therapy ; metabolism ; pathology ; Cell Respiration ; drug effects ; Disease Models, Animal ; Mitochondria, Heart ; metabolism ; pathology ; Pinacidil ; therapeutic use ; Rats ; Rats, Wistar ; Superoxides ; analysis

OBJECTIVETo explore changes of mitochondrial structure and functions, as well as the protection of ligustrazine in the process of myocardial hypertrophy.

METHODSNeonatal myocardial cells were isolated and cultured with angiotensin II (Ang II) for 72 or 96 h. The total protein content was detected using BCA method. The cell diameter was measured by inverted microscope, by which to reflect the proliferation situation of cardiomyocytes. The mitochondrial membrane potential (MMP) was measured by fluorescence microscope. The mitochondrial monoamine oxidase (MAO) activity was detected by spectrophotometer. The mitochondrial cytochrome oxidase (COX) activity and the mitochondrial damage percentage were detected by microplate reader, by which to reflect the damage of mitochondrial outer membrane's structure and the membranes' function. Also, cells were treated with ligustrazine and losartan and then the pharmacological effects on the mitochondrial structure and functions in the myocardial cells treated with Ang II were observed.

RESULTSAt 72 h and 96 h, when compared with the blank group, cells treated with Ang II had increased total protein content (P < 0.01) and enlarged diameter (P < 0.01). Treated with Ang II, the MAO activity and the outer membrane damage percentage of myocardial cells significantly increased (P < 0.01), and mitochondrial COX activity and the mitochondrial MMP significantly decreased (P < 0.01). Compared with the model group at the same time period, ligustrazine significantly reduced myocardial cells' total protein content and myocardial cell diameter, and significantly decreased myocardial cells' MAO activity, increased mitochondrial COX activity, improved the outer membrane damage percentage and inner membrane MMP at 72 and 96 h, all showing statistical difference (P < 0.01, P < 0.05).

CONCLUSIONSDuring the process of myocardial hypertrophy existed the damage to the mitochondrial structure and functions. Ligustrazine protected the mitochondrial structure and functions of the myocardial cells in reversing Ang II induced myocardial cell hypertrophy.

Angiotensin II ; adverse effects ; Animals ; Cardiomyopathy, Hypertrophic ; chemically induced ; metabolism ; pathology ; Cells, Cultured ; Electron Transport Complex IV ; metabolism ; Mitochondria, Heart ; drug effects ; enzymology ; Monoamine Oxidase ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; pathology ; Pyrazines ; pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate whether the cardioprotection of mitochondrial Slo channel (mitoSlo(1) channel) is associated with mitochondrial permeability transition in isolated rat hearts subjected to ischemia and reperfusion.

METHODSIsolated perfused rat hearts were subjected to 30 min regional ischemia (occlusion of left anterior descending artery) and 120 min reperfusion. The infarct size, lactate dehydrogenase (LDH) release during reperfusion and ventricular hemodynamic parameters were measured.

RESULTSPretreatment with mitoSlo(1) channel opener, NS1619 10 micromol/L for 10 min reduced the infarct size and LDH release, and improved the recovery of left ventricular developed pressure, left ventricular end-diastolic pressure, maximal rise/fall rate of left ventricular pressure and coronary flow during reperfusion. Administration of atractyloside (20 micromol/L), an opener of mitochondrial permeability transition pore, for 20 min (last 5 min of ischemia and first 15 min of reperfusion) attenuated the reduction of infarct size and LDH release and improvement of left ventricular performance induced by NS1619. In the isolated mitochondria, a significant inhibition of Ca(2+)-induced swelling was observed when mitochondria were incubated with NS1619.

CONCLUSIONMitoSlo(1) channel activation by NS1619 protects the myocardium against ischemia and reperfusion injury by inhibiting mitochondrial permeability transition pore opening.

Animals ; Atractyloside ; pharmacology ; Cardiotonic Agents ; pharmacology ; Heart ; In Vitro Techniques ; Ischemic Preconditioning, Myocardial ; Mitochondria, Heart ; drug effects ; Mitochondrial Membrane Transport Proteins ; Myocardial Reperfusion Injury ; metabolism ; prevention & control ; Permeability ; drug effects ; Potassium Channels ; metabolism ; Potassium Channels, Calcium-Activated ; metabolism ; Rats

BACKGROUNDMitochondrial dysfunction plays a pivotal role in the progression of left ventricular (LV) remodeling and heart failure (HF). Recombinant human neuregulin-1 (rhNRG-1) improves cardiac function in models of experimental HF and in clinical trials; however, its impact on mitochondrial function during chronic HF remains largely unknown. The purpose of this study was to investigate whether rhNRG-1 could attenuate the functional and structural changes that occur in cardiac mitochondria in a rat model of HF induced by myocardial infarction.

METHODSSixty adult rats underwent sham or coronary ligation to induce HF. Four weeks after ligation, 29 animals with LV ejective fraction ≤ 50% were randomized to receive either vehicle or rhNRG-1 (10 µg×kg(-1)×d(-1), I.V.) for 10 days, another 12 sham-operated animals were given no treatment. Echocardiography was used to determine physiological changes. Mitochondrial membrane potential (MMP), respiratory function and tissue adenosine triphosphate (ATP) production were analyzed. Cytochrome c expression and cardiomyocyte apoptosis were determined. Oxidative stress was evaluated by reactive oxygen species production using fluorescence assays and gene expression of glutathione peroxidase measured by real-time quantitative PCR.

RESULTSCompared with sham-operated animals, vehicle treated HF rats exhibited severe LV remodeling and dysfunction, significant mitochondrial dysfunction, increased mitochondrial cytochrome c release, increased myocyte apoptosis and enhanced oxidative stress. Short-term treatment with rhNRG-1 significantly attenuated LV remodeling and cardiac function. Concomitant with this change, mitochondrial dysfunction was significantly attenuated; with ATP production, MMP and respiratory function restored, cytochrome c release and apoptosis inhibited, and oxidative stress reduced.

CONCLUSIONThe present study demonstrated that rhNRG-1 can significantly improve LV remodeling and cardiac function in the failing heart, this beneficial effect is related to reducing mitochondrial dysfunction, myocyte apoptosis and oxidative stress.

Animals ; Apoptosis ; drug effects ; Blotting, Western ; Echocardiography ; Heart Failure ; Mitochondria ; drug effects ; metabolism ; Myocardial Infarction ; drug therapy ; metabolism ; pathology ; Neuregulin-1 ; therapeutic use ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Real-Time Polymerase Chain Reaction

OBJECTIVETo investigate the effect of hydrogen sulfide (H2S) on mitochondrial function in acute myocardial ischemia in rats.

METHODSAcute myocardial ischemia models were established by ligating the left anterior descending coronary artery (LADC) of rats. Fourty-eight male SD rats were randomly divided into 6 groups (n = 8): sham operation group, ischemia group, ischemia + sodium hydrosulfide (NaHS) low, middle and high dose groups and ischemia + DL-proparglycine(PPG) group. The ultrastructures of myocardial mitochondria were observed with electron microscope. The content of H2S in plasma and the activity of cystathionine-gamma-lyase (CSE) in myocardial tissue of rats were respectively detected. The swelling and activity of myocardial mitochondria were determined. The activities of ATPase, GSH-Px, SOD and the content of malondial-dehyde (MDA) in myocardial mitochondria of rats were also measured.

RESULTSCompared with those of the sham operation group, the content of H2S in plasma, the activity of CSE in myocardial tissue and the activity of myocardium mitochondria were significantly decreased. The activities of ATPase, SOD, GSH-Px in myocardial mitochondria were significantly decreased, The content of malondial dehyde(MDA) in myocardial mitochondria and the swelling of mitochondria were distinctly increased in the ischemia group (P < 0.01). Compared with those of the ischemia group, the content of H2S in plasma and the activity of CSE in myocardial tissue were increased, and the activities of mitochondria, ATPase, SOD, and GSH-Px in myocardial mitochondria were significantly increased in ischemia + NaHS low, middle and high-dose groups; the swelling of mitochondria and the content of MDA in myocardial mitochondria were significantly decreased in ischemia + NaHS middle and high-dose groups (P < 0.05 or P < 0.01). The administration of PPG could partially reduce the myocardial protection of hydrogen sulfide (P < 0.05 or P < 0.01).

CONCLUSIONIt could be concluded that the administration of hydrogen sulfide could enhance the activities of mitochondrial ATPase, SOD, GSH-Px, decrease the level of mitochondrial lipid peroxidation, and play a protective effect against acute myocardial ischemia.

Adenosine Triphosphatases ; metabolism ; Animals ; Glutathione Peroxidase ; metabolism ; Hydrogen Sulfide ; pharmacology ; Lipid Peroxidation ; drug effects ; Male ; Mitochondria, Heart ; drug effects ; metabolism ; physiology ; Myocardial Ischemia ; physiopathology ; prevention & control ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; metabolism

OBJECTIVETo explore the intervention effect and the possibly mechanism of the glutamine (Gln) on the opening change of the permeability transition pore (PTP) in the myocardial mitochondrial membrane under the overtraining state.

METHODS30 SD rats were randomly divided into 3 groups (n = 10): control group (CG group), overtraining group (OG group) and supplementary (Gln) + overtraining group group). Spectrophotometry was used to test the openness of the permeability transition pore in the myocardial mitochondrial membrane. Electrochemistry was used to test the malondialdehyde (MDA) and the glutathione (GSH) content and the phospholipase A2 (PLA2) activity.

RESULTSOG group compared with the GOG group, the absorbance (A0) and the absorbance change (Delta A) were decreased significantly (P < 0.05). Rh123 fluorescence (F0) intensity was significantly increased (P < 0.05). Rhodamine123 (Rh123) fluorescence change (delta F) was significantly decreased (P < 0.05). Compared with the GOG, the mitochondrial GSH was significantly decreased (P < 0.05), the PLA2 activity and the content of MDA were significantly increased (P <0.05).

CONCLUSIONOvertraining could lead to opening increase of permeability transition pore in the myocardial mitochondrial membrane, after overtraining, the production of the reactive oxygen species (ROS) and PLA2 activity were increased, GSH content was decreased. But added exogenous Gln had a significant intervention effect for these changes.

Animals ; Glutamine ; pharmacology ; Glutathione ; metabolism ; Male ; Mitochondria, Heart ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; metabolism ; Mitochondrial Membranes ; drug effects ; physiology ; Myocardium ; metabolism ; Permeability ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism