Early Administration of Fluvastatin, but not at the Onset of Ischemia or Reperfusion, Attenuates Myocardial Ischemia-Reperfusion Injury Through the Nitric Oxide Pathway Rather Than Its Antioxidant Property

Fluvastatin attenuated ischemia/reperfusion-induced autophagy and apoptosis in cardiomyocytes through down-regulation HMGB1/TLR4 signaling pathway

Fluvastatin, a traditional fat-decreasing drug, is widely used for curing cardiovascular disease. Previous reports demonstrated that fluvastatin pretreatment protected against myocardial ischemia/reperfusion (I/R) by inhibiting TLR4 signaling pathway and/or reducing proinflammatory cytokines. However, whether fluvastatin has a cardioprotective effect against apoptosis and autophagy remains unknown. This study aims to evaluate whether the cardioprotective role of fluvastatin in I/R is mediated by high-mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4) pathway via anti-apoptotic and anti-autophagic functions. Sprague-Dawley rats were anesthetized, artificially ventilated and subjected to 30 min of coronary occlusion, followed by 4 h of reperfusion. The animals were randomized into four groups: (i) Sham operation; (ii) I/R; (iii) I/R + low-dosage fluvastatin (10 mg/kg); and (iv) I/R + high-dosage fluvastatin (20 mg/kg). After reperfusion, the hemodynamic parameters, myocardial infarct size, structural alteration of myocardium, apoptosis index, pro-inflammatory cytokine production, Beclin-1, Light chain 3 (LC3), HMGB1, TLR4 and Nuclear factor kappa B (NF-κB) protein levels were measured and recorded. It was found that fluvastatin preconditioning improved left ventricular dysfunction, reduced HMGB1/TLR4/NF-κB expressions, and inhibited cardiomyocyte apoptosis, autophagy, and inflammation reaction. Moreover, treatment with fluvastatin ameliorated myocardial injury by reducing infarct size, causing less damage to cardiac structure, downregulating autophagy-related protein expression and releasing pro-inflammation mediators. Our findings indicate that fluvastatin exerts beneficial effects on cardiac ischemic damage, which may be associated with its anti-autophagic and anti-apoptotic functions via inhibition of HMGB1/TLR4-related pathway during I/R injury.

Polymers and Nanoparticles for Statin Delivery: Current Use and Future Perspectives in Cardiovascular Disease

Atherosclerosis-related coronary artery disease (CAD) is one of the leading sources of mortality and morbidity in the world. Primary and secondary prevention appear crucial to reduce CAD-related complications. In this scenario, statin treatment was shown to be clinically effective in the reduction of adverse events, but systemic administration provides suboptimal results. As an attempt to improve bioavailability and effectiveness, polymers and nanoparticles for statin delivery were recently investigated. Polymers and nanoparticles can help statin delivery and their effects by increasing oral bioavailability or enhancing target-specific interaction, leading to reduced vascular endothelial dysfunction, reduced intimal hyperplasia, reduced ischemia-reperfusion injury, increased cardiac regeneration, positive remodeling in the extracellular matrix, reduced neointimal growth and increased re-endothelization. Moreover, some innovative aspects described in other cardiovascular fields could be translated into the CAD scenario. Recent preclinical studies are underlining the effect of statins in the stimulation and differentiation of endogenous cardiac stem cells, as well as in targeting of local adverse conditions implicated in atherosclerosis, and statin delivery through poly-lactic-co-glycolic acid (PLGA) appears the most promising aspect of current research to enhance drug activity. The present review intends to summarize the current evidence about polymers and nanoparticles for statin delivery in the field of cardiovascular disease, trying to shed light on this topic and identify new avenues for future studies.

Cellular and molecular approaches to enhance myocardial recovery after myocardial infarction

Reperfusion therapy has resulted in significant improvement in post-myocardial infarction morbidity and mortality in over the last 4 decades. Nonetheless, it is well recognized that simply restoring patency of the epicardial artery may not stop or reverse damage at microvascular level, and myocardial salvage is often suboptimal. Numerous efforts have been undertaken to elucidate the mechanisms underlying extensive myonecrosis to facilitate the discovery of therapies to provide additional and incremental benefits over current therapeutic pathways. To date, conclusively effective strategies to promote myocardial recovery have not yet been established. Novel approaches are investigating the foundational cellular and molecular bases of myocardial ischemia and irreversible injury. Herein, we review the emerging concepts and proposed therapies that may improve myocardial protection and reduce infarct size. We examine the preclinical and clinical evidence for reduced infarct size with these strategies, including anti-inflammatory agents, intracellular ion channel modulators, agents affecting the reperfusion injury salvage kinase (RISK) and nitric oxide signaling pathways, modulators of mitochondrial function, anti-apoptotic agents, and stem cell and gene therapy. We review the potential reasons of failures to date and the potential for new strategies to further promote myocardial recovery and improve prognosis.

Effects of Intensive Statin Therapy on Left Ventricular Function in Patients with Myocardial Infarction and Abnormal Glucose Tolerance

Objectives: Abnormal glucose tolerance in patients with acute myocardial infarction (AMI) is associated with greater mortality and adverse cardiovascular effects. As statins possess a range of beneficial pleiotropic effects on the cardiovascular system, we sought to assess the cardioprotective effects of statins on left ventricular function in patients with AMI in relation to glycometabolic state. Methods: In a prospective, randomized trial, 140 patients with AMI were randomized to intensive statin therapy receiving statin loading with 80 mg of rosuvastatin followed by 40 mg daily or standard statin therapy. Patients were assessed with an oral glucose tolerance test and their left ventricular (LV) function was assessed with speckle-tracking echocardiography measuring regional longitudinal systolic strain (RLSS) in the infarct area. Results: Overall RLSS in the infarct area improved by a mean (±SD) of -4.22% (±5.19) in the intensive-care group and -2.48% (±4.01) in the usual-care group after 1 month (p = 0.047). In patients with abnormal glucose tolerance, RLSS improved by -5.01% (±5.28) in the intensive-care group and -2.15% (±4.22) in the usual-care group (p = 0.01). Conclusions: Early high-dose statin treatment improved RLSS in the infarct area in patients with AMI, and a trend of greater improvement was seen in patients with abnormal glucose tolerance.

A review of strategies for infarct size reduction during acute myocardial infarction

Advances in medical and interventional therapy over the last few decades have revolutionized the treatment of acute myocardial infarction. Despite the ability to restore epicardial coronary artery patency promptly through percutaneous coronary intervention, tissue level damage may continue. The reported 30-day mortality after all acute coronary syndromes is 2 to 3%, and around 5% following myocardial infarction. Post-infarct complications such as heart failure continue to be a major contributor to cardiovascular morbidity and mortality. Inadequate microvascular reperfusion leads to worse clinical outcomes and potentially strategies to reduce infarct size during periods of ischemia-reperfusion can improve outcomes. Many strategies have been tested, but no single strategy alone has shown a consistent result or benefit in large scale randomised clinical trials. Herein, we review the historical efforts, current strategies, and potential novel concepts that may improve myocardial protection and reduce infarct size.

A New Therapeutic Modality for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin Induces Cardioprotection from Ischemia-Reperfusion Injury via Activation of PI3K/Akt Pathway and Anti-Inflammation in a Rat Model

Aim

There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction (AMI), for which the effectiveness of interventional reperfusion therapy is hampered by myocardial ischemia-reperfusion (IR) injury. Pretreatment with statins before ischemia is shown to reduce MI size in animals. However, no benefit was found in animals and patients with AMI when administered at the time of reperfusion, suggesting insufficient drug targeting into the IR myocardium. Here we tested the hypothesis that nanoparticle-mediated targeting of pitavastatin protects the heart from IR injury.

Methods and Results

In a rat IR model, poly(lactic acid/glycolic acid) (PLGA) nanoparticle incorporating FITC accumulated in the IR myocardium through enhanced vascular permeability, and in CD11b-positive leukocytes in the IR myocardium and peripheral blood after intravenous treatment. Intravenous treatment with PLGA nanoparticle containing pitavastatin (Pitavastatin-NP, 1 mg/kg) at reperfusion reduced MI size after 24 hours and ameliorated left ventricular dysfunction 4-week after reperfusion; by contrast, pitavastatin alone (as high as 10 mg/kg) showed no therapeutic effects. The therapeutic effects of Pitavastatin-NP were blunted by a PI3K inhibitor wortmannin, but not by a mitochondrial permeability transition pore inhibitor cyclosporine A. Pitavastatin-NP induced phosphorylation of Akt and GSK3β, and inhibited inflammation and cardiomyocyte apoptosis in the IR myocardium.

Conclusions

Nanoparticle-mediated targeting of pitavastatin induced cardioprotection from IR injury by activation of PI3K/Akt pathway and inhibition of inflammation and cardiomyocyte death in this model. This strategy can be developed as an innovative cardioprotective modality that may advance currently unsatisfactory reperfusion therapy for AMI.

Fluvastatin-induced reduction of oxidative stress ameliorates diabetic cardiomyopathy in association with improving coronary microvasculature

Diabetic cardiomyopathy is associated with increased oxidative stress and vascular endothelial dysfunction, which lead to coronary microangiopathy. We tested whether statin-induced redox imbalance improvements could ameliorate diabetic cardiomyopathy and improve coronary microvasculature in streptozotocin-induced diabetes mellitus (DM). Fluvastatin (10 mg/kg/day) or vehicle was orally administered for 12 weeks to rats with or without DM. Myocardial oxidative stress was assessed by NADPH (nicotinamide adenine dinucleotide phosphate) oxidase subunit p22(phox) and gp91(phox) mRNA expression, and myocardial 8-iso-prostaglandin F(2α) (PGF(2α)) levels. Myocardial vascular densities were assessed using anti-CD31 and anti-α-smooth muscle actin (SMA) antibodies. Fluvastatin did not affect blood pressure or plasma cholesterol, but attenuated increased left ventricular (LV) minimum pressure and ameliorated LV systolic dysfunction in DM rats in comparison with vehicle (LV dP/dt, 8.9 ± 1.8 vs 5.4 ± 1.0 × 10(3) mmHg/s, P < 0.05). Myocardial oxidative stress increased in DM, but fluvastatin significantly reduced p22(phox) and gp91(phox) mRNA expression and myocardial PGF(2α) levels. Fluvastatin enhanced myocardial endothelial nitric oxide synthase (eNOS) protein levels and increased eNOS, vascular endothelial growth factor, and hypoxia-inducible factor-1α mRNA expression. CD31-positive cell densities were lower in DM rats than in non-DM rats (28.4 ± 13.2 vs 48.6 ± 4.3/field, P < 0.05) and fluvastatin restored the number (57.8 ± 18.3/field), although there were no significant differences in SMA-positive cell densities between groups. Fluvastatin did not affect cardiac function, oxidative stress, or vessel densities in non-DM rats. These results suggest that beneficial effects of fluvastatin on diabetic cardiomyopathy might result, at least in part, from improving coronary microvasculature through reduction in myocardial oxidative stress and upregulation of angiogenic factor.

Fluvastatin inhibits the induction of inducible nitric oxide synthase, an inflammatory biomarker, in hepatocytes

AIM

Statins (3-hydroxy-3-methylglutaryl coenzyme A [HMG-CoA] reductase inhibitors), which were originally designed to lower plasma cholesterol levels, are increasingly recognized as anti-inflammatory agents. In the inflamed liver, pro-inflammatory cytokines stimulate the induction of inducible nitric oxide synthase (iNOS). Overproduction of NO by iNOS has been implicated as a factor in liver injury. We examined pro-inflammatory cytokine-stimulated hepatocytes as a simple in vitro injury model to determine liver-protective effects of statins. We hypothesized that statins are involved in the downregulation of iNOS, resulting in decreased hepatic inflammation.

METHODS

Hepatocytes were isolated from rats by collagenase perfusion and centrifugation. Primary cultured hepatocytes were treated with interleukin (IL)-1β in the presence or absence of fluvastatin. The induction of iNOS and its signaling pathway were analyzed.

RESULTS

IL-1β produced increased levels of NO. This effect was inhibited by fluvastatin, which exerted its maximal effects at 100 μM. Fluvastatin decreased the levels of iNOS protein and its mRNA expression. Fluvastatin had no effects on IκB degradation and nuclear factor-κB activation. However, fluvastatin inhibited the upregulation of type I IL-1 receptor mRNA and protein expression. Transfection experiments demonstrated that fluvastatin suppressed iNOS induction by the inhibition of promoter transactivation and mRNA stabilization. Fluvastatin reduced the expression of an iNOS gene antisense-transcript, which is involved in iNOS mRNA stability.

CONCLUSION

Results indicate that fluvastatin inhibits the induction of iNOS at both transcriptional and post-transcriptional steps, leading to the prevention of NO production. Fluvastatin may provide therapeutic potential in iNOS induction involved in various liver injuries.

Glycyrrhizin protects rat heart against ischemia-reperfusion injury through blockade of HMGB1-dependent phospho-JNK/Bax pathway

AIM

Glycyrrhizin (GL) has been found to inhibit extracellular HMGB1 cytokine's activity, and protect spinal cord, liver and brain against I/R-induced injury in experimental animals. The purpose of this study was to investigate the protective effect of GL in rat myocardial I/R-induced injury and to elucidate the underlying mechanisms.

METHODS

Male adult Sprague-Dawley rats underwent a 30-min left coronary artery occlusion followed by a 24-h reperfusion. The rats were treated with glycyrrhizin or glycyrrhizin plus recombinant HMGB1 after 30 min of ischemia and before reperfusion. Serum HMGB1, TNF-α and IL-6 levels, and hemodynamic parameters were measured at the onset and different time points of reperfusion. At the end of the experiment, the heart was excised, and the infarct size and histological changes were examined. The levels of Bcl2, Bax and cytochrome c, as well as phospho-ERK1/2, phospho-JNK and phospho-P38 in the heart tissue were evaluated using Western blot analysis, and myocardial caspase-3 activity was measured colorimetrically using BD pharmingen caspase 3 assay kit.

RESULTS

Intravenous administration of GL (10 mg/kg) significantly reduced the infarct size, but did not change the hemodynamic parameters at different time points during reperfusion. GL significantly decreased the levels of serum HMGB1, TNF-α and IL-6. GL changed the distribution of Bax and cytochrome c expression between the mitochondrial and cytosolic fractions in the heart tissue, resulting in inhibition of myocardial apoptosis. Moreover, expression of phospho-JNK, but not ERK1/2 and P38 was decreased by GL in the heart tissue. All of the effects produced by GL treatment were reversed by co-administration with the recombinant HMGB1 (100 μg). Intravenous administration of SP600125, a selective phospho-JNK inhibitor (0.5 mg/kg), attenuated HMGB1-dependent Bax translocation and the subsequent apoptosis.

CONCLUSION

These results demonstrate that GL alleviates rat myocardial I/R-induced injury via directly inhibiting extracellular HMGB1 cytokine activity and blocking the phospho-JNK/Bax pathway.

The Effect of Statins and Other Cardiovascular Medication on Ischemia-Reperfusion Damage in a Human DIEP Flap Model: Theoretical and Epidemiological Considerations

Background. Statins and other cardiovascular medication possess antioxidant capacity. It was examined whether chronic use of these medications protects from the development of ischemia-reperfusion (I/R) related complications after DIEP (Deep Inferior Epigastric Perforator Free Flap) surgery. This paper contains a literature study on the antioxidant working mechanisms of these drugs. Methods. Medical information of 134 DIEP patients (173 flaps) was studied from their medical files. Patient and operative characteristics were registered, as well as I/R related complications. Results. Of the group that didnot use statins, 16.3% developed complications versus 30.8% amongst patients that did use these drugs (P = 0.29). Amongst patients that chronically use other cardiovascular medication, 26.8% developed I/R related complications versus 14.4% of the patients without medication (P = 0.10). Conclusions. Chronic use of statins or other cardiovascular medication didnot decrease the occurrence of I/R related complications after DIEP surgery. Therefore, research should be aimed at evaluating short-term pre-treatment with statins.

Tongxinluo reduces myocardial no-reflow and ischemia-reperfusion injury by stimulating the phosphorylation of eNOS via the PKA pathway

The objective of the present study was to investigate whether pretreatment with single low loading dose of tongxinluo (TXL), a traditional Chinese medicine, 1 h before myocardial ischemia could attenuate no-reflow and ischemia-reperfusion injury by regulating endothelial nitric oxide synthase (eNOS) via the PKA pathway. In a 90-min ischemia and 3-h reperfusion model, minipigs were randomly assigned to the following groups: sham, control, TXL (0.05 g/kg, gavaged 1 h before ischemia), TXL + H-89 (a PKA inhibitor, intravenously infused at a dose of 1.0 μg·kg(-1)·min(-1) 30 min before ischemia), and TXL + N(ω)-nitro-L-arginine (L-NNA; an eNOS inhibitor, intravenously administered at a dose of 10 mg/kg 30 min before ischemia). TXL decreased creatine kinase (CK) activity (P < 0.05) and reduced the no-reflow area from 48.6% to 9.5% and infarct size from 78.5% to 59.2% (P < 0.05), whereas these effects of TXL were partially abolished by H-89 and completely reversed by L-NNA. TXL elevated PKA activity and the expression of PKA, Thr(198) phosphorylated PKA, Ser(1179) phosphorylated eNOS, and Ser(635) phosphorylated eNOS in the ischemic myocardium. H-89 repressed the TXL-induced enhancement of PKA activity and phosphorylation of eNOS at Ser(635), and L-NNA counteracted the phosphorylation of eNOS at Ser(1179) and Ser(635) without an apparent influence on PKA activity. In conclusion, pretreatment with a single low loading dose of TXL 1 h before ischemia reduces myocardial no-reflow and ischemia-reperfusion injury by upregulating the phosphorylation of eNOS at Ser(1179) and Ser(635), and this effect is partially mediated by the PKA pathway.

Pleiotropic effects of statins. - Basic research and clinical perspectives -

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are widely used to lower serum cholesterol levels in the primary and secondary prevention of cardiovascular disease. Recent experimental and clinical evidence suggests that the beneficial effects of statins may extend beyond their cholesterol-lowering effects, to include so-called pleiotropic effects. These cholesterol-independent effects include improving endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammation and oxidation, and stabilizing atherosclerotic plaques. The mechanism underlying some of these pleiotropic effects is the inhibition of isoprenoid synthesis by statins, which leads to the inhibition of intracellular signaling molecules Rho, Rac and Cdc42. In particular, inhibition of Rho and one of its downstream targets, Rho kinase, may be a predominant mechanism contributing to the pleiotropic effects of statins. The aim of the present review is to provide an update on the non-cholesterol-dependent statin effects in the cardiovascular system and highlight some of the recent findings from bench to bedside to support the concept of statin pleiotropy.

Effect of atorvastatin on expression of IL-10 and TNF-alpha mRNA in myocardial ischemia-reperfusion injury in rats

Myocardial ischemia and reperfusion (MI/R) is associated with an intense inflammatory reaction, which may lead to myocyte injury. Because statins protect the myocardium against ischemia-reperfusion injury via a mechanism unrelated to cholesterol lowering, we hypothesized that the protective effect of statins was related to the expression of TNF-alpha (TNF-alpha) and interleukin-10 (IL-10) mRNA. Seventy-two rats were randomly divided into three groups as follows: sham, I/R and I/R+atorvastatin. Atorvastatin (20 mg kg(-1)day(-1)) treatment was administered daily via oral gavage to rats for 2, 7 or 14 days. Ischemia was induced via a 30-min coronary occlusion. Reperfusion was allowed until 2, 7 or 14 days while atorvastatin treatment continued. We measured infarct size, hemodynamics and the plasma levels and the mRNA expression of TNF-alpha and IL-10 in the three groups. We demonstrated that the up-regulation of expression of both TNF-alpha mRNA and IL-10 mRNA was associated the increased plasma levels of TNF-alpha and IL-10 in the ischemic and reperfused myocardium compared with that in the sham group (P<0.01). Atorvastatin treatment prevented ischemia-reperfusion-induced up-regulation of both TNF-alpha and IL-10 mRNA, and improved left ventricular function (P<0.01). Our findings suggested that atorvastatin may attenuate MI/R and better recovery of left ventricle function following ischemia and reperfusion and IL-10 was not directly likely involved in this protective mechanism.

Simvastatin reduces myocardial infarct size via increased nitric oxide production in normocholesterolemic rabbits

OBJECTIVE

Statins have been reported to be protective against myocardial infarction (MI). Moreover, statin drugs upregulate nitric oxide (NO) in coronary artery independent of lipid-lowering effects. However their precise mechanism for MI-protection is unclear. We investigated the effect of lipophilic statin administration in a normocholesterolemic rabbit MI model.

METHODS

Nω-nitro-L-arginine methylester (L-NAME, 10 mg/kg) or vehicle alone was intravenously administered 20 min before inducing ischemia, followed by intravenous administration of simvastatin (5 mg/kg) or saline 10 min before ischemia. Rabbits then underwent 30 min of coronary occlusion followed by 48 h of reperfusion. The at-risk and infarct areas were calculated as a percentage of the total left ventricular slice area.

RESULTS

Determination of infarct size revealed that pre-ischemic treatment with simvastatin reduced infarct size (30.5 ± 4%) in comparison to controls (45.0 ± 3%) (P < 0.05). This infarct size-reducing effect of simvastatin could be completely abrogated by pretreatment with L-NAME (42.0 ± 4%).

CONCLUSIONS

Pre-ischemic treatment with simvastatin reduces MI size via NO production. Simvastatin could be a useful drug for coronary artery disease patients without dyslipidemia as it has direct protective effects.

Effects of HMGB1 on ischemia-reperfusion injury in the rat heart

BACKGROUND

Coronary ischemia-reperfusion (I/R) injury causes cardiomyocyte necrosis in a multi-step process that includes an inflammatory reaction. A recent study has suggested that high-mobility group box 1 (HMGB1) is a late mediator of lethal sepsis and an early mediator of inflammation and necrosis following I/R injury. In the present study a neutralizing monoclonal antibody (mAb) for HMGB1 was used to clarify the role of HMGB1 in cardiac I/R injury.

METHODS AND RESULTS

Rats underwent 30 min of left coronary artery occlusion followed by 60 min reperfusion. An intravenous injection of anti-HMGB1 mAb or control IgG was administered just before reperfusion. The infarct size was enlarged in the anti-HMGB1 mAb group in comparison with the control group (p<0.05). The treatment of anti-HMGB1 mAb significantly increased the plasma troponin-T and norepinephrine (NE) content in the heart in comparison with the control (p<0.05). Moreover, the production of dihydroxyphenylglycol was reduced in the anti-HMGB1-treated group (p<0.05).

CONCLUSION

This study shows for the first time the effects of treatment with neutralizing anti-HMGB1 mAb on I/R injury in the rat heart. The findings support the novel view that I/R-induced HMGB1 may be an important factor in the modulation of interstitial NE.

Potential therapeutic role of statins in neurological disorders

Statins, the inhibitors of HMG-CoA reductase, are currently among the most commonly prescribed agents for the prevention of cardiovascular disease. It is well established that statins reduce cholesterol levels and prevent coronary heart disease. Moreover, evidence suggests that statins have additional properties such as endothelial protection via actions on the nitric oxide synthetase system as well as antioxidant, anti-inflammatory and antiplatelet effects. There is evidence that all these actions might have potential therapeutic implications not only in stroke, but also in various neurological disorders, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis and primary brain tumors. In this review, we summarize the protective effects of statins on various neurological diseases. Currently available data suggest that statins are safe and effective in the treatment of these neurological disorders, although further experiments and new data are required.

Pravastatin Reduces Myocardial Infarct Size Via Increasing Protein Kinase C-Dependent Nitric Oxide, Decreasing Oxyradicals and Opening the Mitochondrial Adenosine Triphosphate-Sensitive Potassium Channels in Rabbits

BACKGROUND

Statins reportedly protect against myocardial infarction, but the precise mechanism is unclear.

METHODS AND RESULTS

Rabbits underwent 30 min of coronary occlusion followed by 48 h of reperfusion. Pravastatin (1 or 5 mg/kg) or saline was intravenously administered 10 min before ischemia. Pravastatin (5 mg/kg) was also administered 10 min before reperfusion. N(omega)-nitro-L-arginine methylester (L-NAME, 10 mg/kg), chelerythrine (5 mg/kg) or 5-hydroxydecanoic acid sodium salt (5-HD, 5 mg/kg) was intravenously administered 10 min before pravastatin injection. The infarct size was determined. The myocardial interstitial levels of 2,5-dihydroxybenzoic acid (DHBA) and nitrogen oxide (NOx), and the intensity of myocardial dihydroethidium staining were measured. Pre-ischemic treatment with pravastatin reduced the infarct size (34+/-5% and 24+/-4%, 1 and 5 mg/kg, respectively), but not pre-reperfusion treatment (42.1+/-3.7%), compared with the control (45+/-3%). This effect was blocked by L-NAME (42.6+/-4%), chelerythrine (50.9+/-3%) and 5-HD (52.7+/-2%). Pre-ischemic treatment with pravastatin increased myocardial NOx levels, and attenuated both the 2,5-DHBA level and the intensity of dihydroethidium staining during reperfusion. Chelerythrine abolished the increase in NOx levels by pravastatin.

CONCLUSION

Pre-ischemic treatment with pravastatin reduces the myocardial infarct size via protein kinase C-dependent nitric oxide production, decreasing hydroxyl radicals and superoxide, and opening the mitochondrial adenosine triphosphate-sensitive potassium channels.