Cajanus cajan ameliorated CCl4-induced oxidative stress in Wistar rats via the combined mechanisms of anti-inflammation and mitochondrial-membrane transition pore inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Liver diseases is a public health issue in sub-saharan Africa and has been reported to be the major cause of many hospital admissions. Oxidative stress, mitochondrial dysfunction and inflammation play important roles in several diseases including liver injury. Cajanus cajan is an indigenous medicinal plant useful in the traditional treatment of jaundice, inflammation and liver injury.

AIM OF STUDY

This study assessed the effects of methanol extract Cajanus cajan (MECC) on mitochondrial permeability transition (mPT) pore opening, biomarkers of oxidative stress and inflammation in CCl_4-induced liver injury in rats.

METHODS

Wistar albino rats (200-210g) were completely randomized into five (5) groups of six animals each. Group I (control) was given distilled water orally once daily. Animals in group II were administered CCl₄ in parafin (1:1) at a dose of 0.5 mL/kg i.p on the seventh day. Animals in groups III, IV and V were administered methanol extract of Cajanus cajan (MECC) at doses of 100, 200 mg/kg and silymarin (100 mg/kg) respectively for 7 days prior to a single intraperitoneal dose of CCl₄. After 24 h of CCl₄ treatment, serum and liver tissues were collected. Mitochondrial permeability transition (mPT) pore opening, mitochondrial ATPase activities and biomarkers of oxidative stress were determined spectrophotometrically. Tumor necrosis factor (TNFα), NF-κB and COX-2 were determined by immunohistochemistry and the phytochemicals present in the extract were determined by GC-MS.

RESULTS

Liver enzyme (AST, ALP, ALT and γGT) activities and MDA levels were significantly decreased in rats pretreated with MECC at the dose of 100, 200 and silymarin (100 mg/kg) when compared to the rats administered CCl₄ alone (p < 0.05). GSH, GST, CAT and SOD increased and the expressions of TNFα, NF-κB and COX- 2 were also reduced when compared to the CCl₄- treated animals. In addition, the liver histopathological analyses revealed that MECC markedly alleviated inflammatory cell infiltration, hepatic fibrosis, hepatocyte ballooning, necrosis and severe apoptosis of hepatocytes induced by CCl₄. GC-MS analysis yielded 23 compounds including flavonoids, terpenoids and fatty acids.

CONCLUSION

Cajanus cajan leaf extract elicited hepatoprotective action on CCl₄-induced liver injury via inhibition of mPT pore opening, prevention of CCl₄-induced hepatic oxidative stress and suppression of inflammatory response thus it may become useful for chemoprevention of liver injury. This supports its traditional use.

Nanoparticle-Mediated Simultaneous Targeting of Mitochondrial Injury and Inflammation Attenuates Myocardial Ischemia-Reperfusion Injury

Background The opening of mitochondrial permeability transition pore and inflammation cooperatively progress myocardial ischemia-reperfusion (IR) injury, which hampers therapeutic effects of primary reperfusion therapy for acute myocardial infarction. We examined the therapeutic effects of nanoparticle-mediated medicine that simultaneously targets mitochondrial permeability transition pore and inflammation during IR injury. Methods and Results We used mice lacking cyclophilin D (CypD, a key molecule for mitochondrial permeability transition pore opening) and C-C chemokine receptor 2 and found that CypD contributes to the progression of myocardial IR injury at early time point (30-45 minutes) after reperfusion, whereas C-C chemokine receptor 2 contributes to IR injury at later time point (45-60 minutes) after reperfusion. Double deficiency of CypD and C-C chemokine receptor 2 enhanced cardioprotection compared with single deficiency regardless of the durations of ischemia. Deletion of C-C chemokine receptor 2, but not deletion of CypD, decreased the recruitment of Ly-6Chigh monocytes after myocardial IR injury. In CypD-knockout mice, administration of interleukin-1β blocking antibody reduced the recruitment of these monocytes. Combined administration of polymeric nanoparticles composed of poly-lactic/glycolic acid and encapsulating nanoparticles containing cyclosporine A or pitavastatin, which inhibit mitochondrial permeability transition pore opening and monocyte-mediated inflammation, respectively, augmented the cardioprotection as compared with single administration of nanoparticles containing cyclosporine A or pitavastatin after myocardial IR injury. Conclusions Nanoparticle-mediated simultaneous targeting of mitochondrial injury and inflammation could be a novel therapeutic strategy for the treatment of myocardial IR injury.

Aconitine attenuates mitochondrial dysfunction of cardiomyocytes via promoting deacetylation of cyclophilin-D mediated by sirtuin-3

ETHNOPHARMACOLOGICAL RELEVANCE

Aconite is a processed product of seminal root of perennial herbaceous plant Aconitum Carmichaclii Debx. of Ranunculaceae. It has the effects of warming and tonifying heart yang and restoring yang to save from collapse. Aconitine is the main effective constituent of aconite and used to prevent and treat heart disease. However, how aconitine exerts myocardial protection is still poorly understood.

AIM OF THE STUDY

The present study aimed to investigate the effects of aconitine on mitochondrial dysfunction and explore its mechanism of action.

MATERIALS AND METHODS

The model of myocardial injury was induced by Angiotensin II (Ang II) (1 × 10-6 mol L-1), and H9c2 cells were incubated with different concentrations of aconitine. The effect of aconitine on mitochondrial was determined by flow cytometry, transmission electron microscopy, luciferase, Seahorse technique and Western blot. The effects of aconitine on sirtuin-3 (Sirt3) activity and Cyclophilin D (CypD) acetylation were detected by immunofluorescence, RT-PCR and co-immunoprecipitation.

RESULTS

We demonstrate that aconitine alleviates the energy metabolic dysfunction of H9c2 cells by activating Sirt3 to deacetylate CypD and inhibiting mitochondrial permeability transition pore (mPTP) opening. In cardiomyocytes, aconitine significantly reduced mitochondrial fragmentation, inhibited acetylation of CypD, suppressed the mPTP opening, mitigated mitochondrial OXPHOS disorders, and improved the synthesis ability of ATP. In contrast, Sirt3 deficiency abolished the effects of aconitine on mPTP and OXPHOS, indicating that aconitine improves mitochondrial function by activating Sirt3.

CONCLUSIONS

These results showed that aconitine attenuated the energy metabolism disorder by promoting Sirt3 expression and reducing CypD-mediated mPTP excess openness, rescuing mitochondrial function. Improve mitochondrial function may be a therapeutic approach for treating heart disease, which will generate fresh insight into the cardioprotective of aconitine.

Preconditioning and anti-apoptotic effects of Metformin and Cyclosporine-A in an isolated bile duct-ligated rat heart

Despite all previous studies relating to the mechanism of cirrhotic cardiomyopathy (CCM), the role of cirrhosis on Ischemic Preconditioning (IPC) has not yet been explored. The present study strives to assess the cardioprotective role of IPC in bile duct ligated (BDL) rats as well as the cardioprotective role of Cyclosporin-A (CsA) and Metformin (Met) in CCM. Cirrhosis was induced by bile duct ligation (BDL). Rats' hearts were isolated and attached to a Langendorff Apparatus. The pharmacological preconditioning with Met and CsA was done before the main ischemia. Myocardial infarct size, hemodynamic and electrophysiological parameters, biochemical markers, and apoptotic indices were determined at the end of the experiment. Infarct size, apoptotic indices, arrhythmia score, and incidence of VF decreased significantly in the IPC group in comparison with the I/R group. These significant decreases were abolished in the IPC (BDL) group. Met significantly decreased the infarct size and apoptotic indices compared with I/R (BDL) and normal groups, while CsA led to similar decreases except in the level of caspase-3 and -8. Met and CsA decreased and increased the arrhythmia score and incidence of VF in the BDL groups, respectively. Functional recovery indices decreased in the I/R (BDL) and IPC (BDL) groups. Met improved these parameters. Therefore, the current study depicted that the cardioprotective effect of Met and CsA on BDL rats is mediated through the balance between pAMPK and apoptosis in the mitochondria.

Reduction of elevated proton leak rejuvenates mitochondria in the aged cardiomyocyte

Aging-associated diseases, including cardiac dysfunction, are increasingly common in the population. However, the mechanisms of physiologic aging in general, and cardiac aging in particular, remain poorly understood. Age-related heart impairment is lacking a clinically effective treatment. Using the model of naturally aging mice and rats, we show direct evidence of increased proton leak in the aged heart mitochondria. Moreover, our data suggested ANT1 as the most likely site of mediating increased mitochondrial proton permeability in old cardiomyocytes. Most importantly, the tetra-peptide SS-31 prevents age-related excess proton entry, decreases the mitochondrial flash activity and mitochondrial permeability transition pore opening, rejuvenates mitochondrial function by direct association with ANT1 and the mitochondrial ATP synthasome, and leads to substantial reversal of diastolic dysfunction. Our results uncover the excessive proton leak as a novel mechanism of age-related cardiac dysfunction and elucidate how SS-31 can reverse this clinically important complication of cardiac aging.

Comparison of Effects of Metformin, Phenformin, and Inhibitors of Mitochondrial Complex I on Mitochondrial Permeability Transition and Ischemic Brain Injury

Damage to cerebral mitochondria, particularly opening of mitochondrial permeability transition pore (MPTP), is a key mechanism of ischemic brain injury, therefore, modulation of MPTP may be a potential target for a neuroprotective strategy in ischemic brain pathologies. The aim of this study was to investigate whether biguanides-metformin and phenformin as well as other inhibitors of Complex I of the mitochondrial electron transfer system may protect against ischemia-induced cell death in brain slice cultures by suppressing MPTP, and whether the effects of these inhibitors depend on the age of animals. Experiments were performed on brain slice cultures prepared from 5-7-day (premature) and 2-3-month old (adult) rat brains. In premature brain slice cultures, simulated ischemia (hypoxia plus deoxyglucose) induced necrosis whereas in adult rat brain slice cultures necrosis was induced by hypoxia alone and was suppressed by deoxyglucose. Phenformin prevented necrosis induced by simulated ischemia in premature and hypoxia-induced-in adult brain slices, whereas metformin was protective in adult brain slices cultures. In premature brain slices, necrosis was also prevented by Complex I inhibitors rotenone and amobarbital and by MPTP inhibitor cyclosporine A. The latter two inhibitors were protective in adult brain slices as well. Short-term exposure of cultured neurons to phenformin, metformin and rotenone prevented ionomycin-induced MPTP opening in intact cells. The data suggest that, depending on the age, phenformin and metformin may protect the brain against ischemic damage possibly by suppressing MPTP via inhibition of mitochondrial Complex I.

Cyclosporine A Plus Ischemic Postconditioning Improves Neurological Function in Rats After Cardiac Resuscitation

BACKGROUND AND OBJECTIVE

Attenuation of neuronal apoptosis helps maintain neurological function in patients after cardiac arrest. After ischemia-reperfusion, both cyclosporin A (CsA) and ischemic postconditioning independently protect mitochondria and thus reduce nerve injury. This study employed a rat model to evaluate the neuroprotective effect of combining ischemic postconditioning with CsA after cardiopulmonary resuscitation (CPR).

METHODS

Rats were apportioned equally to model control, postconditioned, CsA-treated, or CsA + postconditioned groups. Asphyxial cardiac arrest was imposed using modified Utstein-style guidelines. In the appropriate groups, postconditioning was implemented by ischemia and reperfusion (clamping and loosening the left femoral artery); CsA treatment was delivered with a single intravenous dose. Neurological deficits were scored at different times after CPR. Histological evaluation and electron microscopy were used to evaluate tissue damage, and TUNEL and flow cytometry were used to measure the apoptotic rate of hippocampal neurons and size of the mitochondrial permeability transition pore (mPTP) opening.

RESULTS

The apoptotic rate was significantly lower in the postconditioned and CsA-treated groups compared with the model control and lowest in the CsA + postconditioned group. By histological evaluation and electron microscopy, the least damage was observed in the CsA + postconditioned group. The neurological deficit score of the CsA + postconditioned group was significantly higher than that of the CsA-treated group, but the size of the mPTP openings of these two groups was comparable.

CONCLUSION

Ischemic postconditioning combined with CsA exerted a better neuroprotective effect after CPR than did either postconditioning or CsA alone. Inhibiting the opening of the mPTP is not the only neuroprotective mechanism.