Allopurinol attenuates oxidative stress and cardiac fibrosis in angiotensin II-induced cardiac diastolic dysfunction

Centella asiatica (L.) Urb. Prevents Hypertension and Protects the Heart in Chronic Nitric Oxide Deficiency Rat Model

Background: Hypertension is a major risk factor for cardiovascular disease (CVD), which is the number one cause of global mortality. The potential use of natural products to alleviate high blood pressure has been demonstrated to exert a cardioprotective effect. Centella asiatica (L.) Urb. belongs to the plant family Apiaceae (Umbelliferae). It contains a high amount of triterpenoid and flavonoid that have antioxidant properties and are involved in the renin-angiotensin-aldosterone system which is an important hormonal system for blood pressure regulation. Objective: This study aimed to investigate the effects of C. asiatica ethanolic extract on blood pressure and heart in a hypertensive rat model, which was induced using oral N(G)-nitro-l-arginine methyl ester (l-NAME). Methods: Male Sprague-Dawley rats were divided into five groups and were given different treatments for 8 weeks. Group 1 only received deionized water. Groups 2, 4, and 5 were given l-NAME (40 mg/kg, orally). Groups 4 and 5 concurrently received C. asiatica extract (500 mg/kg, orally) and captopril (5 mg/kg, orally), respectively. Group 3 only received C. asiatica extract (500 mg/kg body weight, orally). Systolic blood pressure (SBP) was measured at weeks 0, 4, and 8, while serum nitric oxide (NO) was measured at weeks 0 and 8. At necropsy, cardiac and aortic malondialdehyde (MDA) contents, cardiac angiotensin-converting enzyme (ACE) activity, and serum level of brain natriuretic peptide (BNP) were measured. Results: After 8 weeks, the administrations of C. asiatica extract and captopril showed significant (p < 0.05) effects on preventing the elevation of SBP, reducing the serum nitric oxide level, as well as increasing the cardiac and aortic MDA content, cardiac ACE activity, and serum brain natriuretic peptide level. Conclusion: C. asiatica extract can prevent the development of hypertension and cardiac damage induced by l-NAME, and these effects were comparable to captopril.

Insight into the Pro-inflammatory and Profibrotic Role of Macrophage in Heart Failure With Preserved Ejection Fraction

The prevalence of heart failure (HF) with preserved ejection fraction (HFpEF) is higher than that of HF with reduced/midrange ejection fraction (HFrEF/HFmrEF). However, no evidence-based guidelines for managing HFpEF have been generated. The current body of knowledge indicates that fibrosis and inflammation are important components of the cardiac remodeling process in HFpEF. In addition, macrophages potentially play an important role in pro-inflammatory and profibrotic processes in HFpEF patients, whereas HFpEF comorbidities could be a driving force for systemic microvascular inflammation and endothelial dysfunction. Under such circumstances, macrophages reportedly contribute to inflammation and fibrosis through 3 phases namely, inflammation, repair, and resolution. Signal transduction pathway-targeted therapies using animal experiments have generated important discoveries and breakthroughs for understanding the underlying mechanisms of HFpEF. However, only a handful of studies have reported promising results using human trials. Further investigations are therefore needed to elucidate the exact mechanisms underlying HFpEF and immune-pathogenesis of cardiac fibrosis.

Molecular Mechanisms of Obesity-Linked Cardiac Dysfunction: An Up-Date on Current Knowledge

Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.

Hyperuricemia and the Risk of Heart Failure: Pathophysiology and Therapeutic Implications

The association between hyperuricemia and cardiovascular disease (CVD) has been reported and studied in the past two decades. Xanthine oxidase (XO) induced uric acid (UA) serves as a risk factor and has the independent prognostic and functional impact of heart failure (HF), but whether it plays a positive role in the pathogenesis of HF has remained unclear. Growing evidence suggest the up-regulated XO avtivity and increased production of free oxygen radical (ROS) correspondingly are the core pathogenesis of HF with hyperuricemia, which results in a whole cluster of pathophysiologic cardiovascular effects such as oxidative stress, endothelial dysfunction, vascular inflammation, left ventricular (LV) dysfunction as well as insulin resistance (IR). The use of XO inhibition represents a promising therapeutic choice in patients with HF due to its dual effect of lowering serum UA levels as well as reducing ROS production. This review will discuss the pathophysiologic mechanisms of hyperuricemia with HF, the targeted therapeutic interventions of UA lowering therapies (ULT) with XO inhibition and mechanism underlying beneficial effects of ULT. In addition, the review also summarizes current evidence on the role of ULT in HF and compares CV risk between allopurinol and febuxostat for practical and clinical purposes. Guidelines and implementation of CV risk management in daily practice will be discussed as well.

Redox State in Atrial Fibrillation Pathogenesis and Relevant Therapeutic Approaches

BACKGROUND

Myocardial redox state is a critical determinant of atrial biology, regulating cardiomyocyte apoptosis, ion channel function, and cardiac hypertrophy/fibrosis and function. Nevertheless, it remains unclear whether the targeting of atrial redox state is a rational therapeutic strategy for atrial fibrillation prevention.

OBJECTIVE

To review the role of atrial redox state and anti-oxidant therapies in atrial fibrillation.

METHOD

Published literature in Medline was searched for experimental and clinical evidence linking myocardial redox state with atrial fibrillation pathogenesis as well as studies looking into the role of redoxtargeting therapies in the prevention of atrial fibrillation.

RESULTS

Data from animal models have shown that altered myocardial nitroso-redox balance and NADPH oxidases activity are causally involved in the pathogenesis of atrial fibrillation. Similarly experimental animal data supports that increased reactive oxygen / nitrogen species formation in the atrial tissue is associated with altered electrophysiological properties of atrial myocytes and electrical remodeling, favoring atrial fibrillation development. In humans, randomized clinical studies using redox-related therapeutic approaches (e.g. statins or antioxidant agents) have not documented any benefits in the prevention of atrial fibrillation development (mainly post-operative atrial fibrillation risk).

CONCLUSION

Despite strong experimental and translational data supporting the role of atrial redox state in atrial fibrillation pathogenesis, such mechanistic evidence has not been translated to clinical benefits in atrial fibrillation risk in randomized clinical studies using redox-related therapies.

Traditional Chinese medicine baoxin decoction improves cardiac fibrosis of rats with dilated cardiomyopathy

We investigated the effect of baoxin decoction (BXD) on myocardial fibrosis and clarified the possible mechanism of action. Dilated myocardiopathy was induced by doxorubicin injected intraperitoneally for 6 weeks. Rats that demonstrated dilated myocardiopathy were randomly divided into five groups plus a control group. Three groups were treated with BXD (7.5/kg, 15 g/kg and 30 g/kg) daily for 4 weeks. One group was treated with 8.75 g/kg of captopril (positive control), and with physiologic saline (negative control). Cardiac function was evaluated using echocardiography. Hematoxylin and eosin, and Massons trichrome staining were performed, PICP and PIIINP were assessed by ELISA, the expression of galectin-3 and collagen types I and III was evaluated with reverse transcription-quantitative PCR, and interrelated proteins were detected by western blot analysis. BXD downregulated galectin-3, collagen I and III and was correlated with a high expression of fibrosis markers. It also significantly decreased myocardial collagen volume fraction (CVF), together with markedly preventing the upregulation of collagen I and III. In addition, BXD downregulated the expression of TGF-β1 and Smad3 in the myocardial fibrosis rats. Therefore, BXD treatment significantly improved cardiac function and alleviated myocardial fibrosis in a rat model of doxorubicin-induced dilated cardiomyopathy (DCM), which is the mechanism that may be associated with inhibiting the TGF-β1 signaling pathway.

Cardiac stem cells transplantation enhances the expression of connexin 43 via the ANG II/AT1R/TGF-beta1 signaling pathway in a rat model of myocardial infarction

BACKGROUND

In this study, we hypothesized that CSCs mediated the expression of Cx43 after transplantation post MI via the ANG II/AT1R/TGF-beta1 signaling pathway.

METHODS

Myocardial infarction (MI) was induced in twenty male Sprague-Dawley rats. The rats were randomized into two groups and were then received the injection of 5 × 10(6) CSCs labeled with PKH26 in phosphate buffer solution (PBS) or equal PBS alone into the infarct anterior ventricular free wall two weeks after MI. Six weeks later, relevant signaling molecules involved were all examined.

RESULTS

In the CSCs group, an increased expression of Cx43 could be observed in different zones of the left ventricle (P<0.01). There was a significant reduction of the angiotensin II (ANG II) level in plasma and different regions of the left ventricular cardiac tissues (P<0.05; P<0.01). The angiotensin II type I receptor (AT1R) was decreased accompanied with an enhanced expression of angiotensin II type II receptor (AT2R) (P<0.01). Transforming growth factor beta-1(TGF-beta1) was downregulated (P<0.01). The expression of mothers against decapentaplegic homolog (SMAD) proteins including SMAD2 and SMAD3 was attenuated whereas SMAD7 was elevated (P<0.01, P<0.01, P<0.05). In addition, the expression of mitogen-activated protein kinases (MAPKs) including extracellular kinases 1/2 (ERK1/2) and p38 was also found to be reduced (P<0.01).

CONCLUSION

CSCs transplantation could enhance the level of Cx43 after MI. They might function through intervening the ANGII/AT1R/TGF-beta1 signaling pathway to regulate the expression of Cx43.

Xanthine Oxidase Inhibitor, Allopurinol, Prevented Oxidative Stress, Fibrosis, and Myocardial Damage in Isoproterenol Induced Aged Rats

We evaluated the preventive effect of allopurinol on isoproterenol (ISO) induced myocardial infarction in aged rats. Twelve- to fourteen-month-old male Long Evans rats were divided into three groups: control, ISO, and ISO + allopurinol. At the end of the study, all rats were sacrificed for blood and organ sample collection to evaluate biochemical parameters and oxidative stress markers analyses. Histopathological examinations were also conducted to assess inflammatory cell infiltration and fibrosis in heart and kidneys. Our investigation revealed that the levels of oxidative stress markers were significantly increased while the level of cellular antioxidants, catalase activity, and glutathione concentration in ISO induced rats decreased. Treatment with allopurinol to ISO induced rats prevented the elevated activities of AST, ALT, and ALP enzymes, and the levels of lipid peroxidation products and increased reduced glutathione concentration. ISO induced rats also showed massive inflammatory cells infiltration and fibrosis in heart and kidneys. Furthermore, allopurinol treatment prevented the inflammatory cells infiltration and fibrosis in ISO induced rats. In conclusion, the results of our study suggest that allopurinol treatment is capable of protecting heart of ISO induced myocardial infarction in rats probably by preventing oxidative stress, inflammation, and fibrosis.

Allopurinol alleviates hypertension and proteinuria in high fructose, high salt and high fat induced model of metabolic syndrome

Metabolic syndrome (MetS) is a global epidemic associated with great socioeconomic and public health impact. Prevalence of the MetS has been consistently associated with cardiorenal mortality. The objective of this study was to investigate the effect of allopurinol treatment on various components of an established MetS in rats. In a first group, MetS was induced in male Wistar rats by the addition of 10% fructose to drinking water and placing the rats on high-fat and high-salt diet for 12 weeks (M). In the second group, MetS was induced for 12 weeks plus allopurinol administration (20 mg/kg/d) orally for 4 weeks starting at week 9 (MA). The third group was control (C) group that received a normal diet. The M group had higher blood pressure (BP) (85.5 ± 3.17 vs 66.1 ± 3.3 mm Hg) and proteinuria (1.8 ± 0.3 vs 0.59 ± 0.13 g/d) compared with the C group. Allopurinol reversed the BP and proteinuria in MA rats to the control level. Allopurinol administration suppressed the low-grade inflammation associated with MetS and reversed the increases in kidney transforming growth factor beta and urine 8-isoprostane acid observed in the MA group to control levels. In addition, allopurinol reduced angiotensin II and angiotensin receptor type 1 levels in the kidney of MA rats compared with the M group. The administration of allopurinol for short term in an established MetS model reduced features of the MetS especially hypertension and proteinuria. Addition of allopurinol to the therapy of MetS may provide superior means to alleviate hypertension and proteinuria associated with MetS.

Xanthine oxidase inhibition alleviates the cardiac complications of insulin resistance: effect on low grade inflammation and the angiotensin system

BACKGROUND

We have previously shown that hyperuricemia plays an important role in the vascular complications of insulin resistance (IR). Here we investigated the effect of xanthine oxidase (XO) inhibition on the cardiac complications of IR.

METHODS

IR was induced in rats by a high fructose high fat diet for 12 weeks. Allopurinol, a standard XO inhibitor, was administered in the last 4 weeks before cardiac hemodynamics and electrocardiography, serum glucose, insulin, tumor necrosis factor alpha (TNFα), 8-isoprostane, uric acid, lactate dehydrogenase (LDH) and XO activity were measured. Expression of cardiac angiotensin II (AngII) and angiotensin receptor 1 (AT1) were assessed by immunofluorescence.

RESULTS

IR animals had significant hyperuricemia which was inhibited by allopurinol administration. IR was associated with impaired ventricular relaxation (reflected by a decreased diastolic pressure increment and prolonged diastolic duration) and XO inhibition greatly attenuated impaired relaxation. IR was accompanied by cardiac ischemia (reflected by increased QTc and T peak trend intervals) while XO inhibition alleviated the ECG abnormalities. When subjected to isoproterenol-induced ischemia, IR hearts were less resistant (reflected by larger ST height depression and higher LDH level) while XO inhibition alleviated the accompanying ischemia. In addition, XO inhibition prevented the elevation of serum 8-isoprostane and TNFα, and blocked elevated AngII and AT1 receptor expression in the heart tissue of IR animals. However, XO inhibition did not affect the developed hyperinsulinemia or dyslipidemia.

CONCLUSIONS

XO inhibition alleviates cardiac ischemia and impaired relaxation in IR through the inhibition of low grade inflammation and the angiotensin system.

Uric acid promotes left ventricular diastolic dysfunction in mice fed a Western diet

The rising obesity rates parallel increased consumption of a Western diet, high in fat and fructose, which is associated with increased uric acid. Population-based data support that elevated serum uric acids are associated with left ventricular hypertrophy and diastolic dysfunction. However, the mechanism by which excess uric acid promotes these maladaptive cardiac effects has not been explored. In assessing the role of Western diet-induced increases in uric acid, we hypothesized that reductions in uric acid would prevent Western diet-induced development of cardiomyocyte hypertrophy, cardiac stiffness, and impaired diastolic relaxation by reducing growth and profibrotic signaling pathways. Four-weeks-old C57BL6/J male mice were fed excess fat (46%) and fructose (17.5%) with or without allopurinol (125 mg/L), a xanthine oxidase inhibitor, for 16 weeks. The Western diet-induced increases in serum uric acid along with increases in cardiac tissue xanthine oxidase activity temporally related to increases in body weight, fat mass, and insulin resistance without changes in blood pressure. The Western diet induced cardiomyocte hypertrophy, myocardial oxidative stress, interstitial fibrosis, and impaired diastolic relaxation. Further, the Western diet enhanced activation of the S6 kinase-1 growth pathway and the profibrotic transforming growth factor-β1/Smad2/3 signaling pathway and macrophage proinflammatory polarization. All results improved with allopurinol treatment, which lowered cardiac xanthine oxidase as well as serum uric acid levels. These findings support the notion that increased production of uric acid with intake of a Western diet promotes cardiomyocyte hypertrophy, inflammation, and oxidative stress that lead to myocardial fibrosis and associated impaired diastolic relaxation.

Allopurinol is an independent determinant of improved arterial stiffness in chronic kidney disease: a cross-sectional study

Background

Arterial stiffness is increased in patients with CKD and is a powerful predictor of cardiovascular morbidity and mortality. Use of the xanthine oxidase inhibitor allopurinol has been shown to improve endothelial function, reduce left ventricular hypertrophy and possibly improve cardiovascular outcome. We explored the relationship between use of allopurinol and arterial stiffness in patients with chronic kidney disease (CKD).

Methods

Cross-sectional observational study of 422 patients with CKD with evidence of, or at high risk of, renal disease progression. Arterial stiffness was determined by carotid-femoral pulse wave velocity (PWV).

Results

The mean age was 63±16 years, median estimated glomerular filtration rate was 25 (interquartile range: 19–31) ml/min/1.73 m² and mean PWV was 10.2±2.4 m/s. Seventy-seven patients (18%) were receiving regular allopurinol, 61% at a dose of 100 mg/day (range: 50–400 mg/day). Patients receiving allopurinol had significantly lower peripheral pulse pressure, central pulse pressure, central systolic blood pressure, serum uric acid level tissue advanced glycation end product levels but comparable high-sensitivity C-reactive protein levels. Use of allopurinol was associated with lower PWV. After adjusting for age, gender, ethnicity, tissue advanced glycation end product level, peripheral pulse pressure, smoking pack years, presence of diabetes mellitus and use of angiotensin converting enzyme inhibitor or angiotensin II receptor blocker, the use of allopurinol remained a significant independent determinant of PWV (mean difference: −0.63 m/s; 95% CI, −0.09 to −1.17 m/s, p = 0.02).

Conclusion

In patients with CKD, use of allopurinol is independently associated with lower arterial stiffness. This study provides further justification for a large definitive randomised controlled trial examining the therapeutic potential of allopurinol to reduce cardiovascular risk in people with CKD.

Angiotensin II and oxidative stress in the failing heart

SIGNIFICANCE

Despite recent medical advances, cardiovascular disease and heart failure (HF) continue to be major health concerns, and related mortality remains high. As a result, investigation of the mechanisms involved in the development of HF continues to be an active field of study.

RECENT ADVANCES

The renin-angiotensin system (RAS) and its effector molecule, angiotensin (Ang) II, affect cardiac function through both systemic and local actions, and have been shown to play a major role in cardiac remodeling and dysfunction in the failing heart. Many of the downstream effects of AngII signaling are mediated by elevated levels of reactive oxygen species (ROS) and oxidative stress, which have also been implicated in the pathology of HF.

CRITICAL ISSUES

Inhibitors of the RAS have proven beneficial in the treatment of patients at risk for and suffering from HF, but remain only partially effective. ROS can be generated from several different sources, and the oxidative state is normally tightly regulated in the heart. How AngII increases ROS levels and causes dysregulation of the cardiac oxidative state has been the subject of considerable interest in recent years.

FUTURE DIRECTIONS

A better understanding of this process and the mechanisms involved should lead to the development of more effective HF therapies and improved outcomes.

Apocynin attenuates oxidative stress and cardiac fibrosis in angiotensin II-induced cardiac diastolic dysfunction in mice

AIM

To investigate whether apocynin, a NADPH oxidase inhibitor, produced cardioproteictive effects in Ang II-induced hypertensive mice, and to elucidate the underlying mechanisms.

METHODS

C57BL/6 mice were subcutaneously infused Ang II for 4 weeks to mimic cardiac remodeling and fibrosis. Concomitantly the mice were administered apocynin (100 mg·kg(-1)·d(-1)) or/and the aldosterone receptor blocker eplerenone (200 mg·kg(-1)·d(-1)) via gavage for 4 weeks. Systolic blood pressure (SBP) and heart rate were measured, and transthoracic echocardiography was performed. For in vitro study, cardiac fibroblasts were treated with Ang II (10(-7) mol/L) in the presence of apocynin (10(-5) mol/L) or/and eplerenone (10(-5) mol/L). Immunohistochemistry and Western blotting were used to quantify the expression levels of NADPH oxidase and osteopontin (OPN) proteins in the cells.

RESULTS

Both apocynin and eplerenone significantly decreased SBP, and markedly improved diastolic dysfunction in Ang II-induced hypertensive mice, accompanied with ameliorated oxidative stress and cardiac fibrosis. In the Ang II-treated cardiac fibroblasts, the expression levels of NOX4 and OPN proteins were markedly upregulated. Both Apocynin and eplerenone significantly suppressed the increased expression levels of NOX4 and OPN proteins in the Ang II-treated cells. In all the experiments, apocynin and eplerenone produced comparable effects. Co-administration of the two agents did not produce synergic effects.

CONCLUSION

Apocynin produces cardioproteictive effects comparable to those of eplerenone. The beneficial effects of apocynin on myocardial oxidative stress and cardiac fibrosis might be mediated partly through a pathway involving NADPH oxidase and OPN.

Inhibition of signal transducer and activator of transcription 3 (STAT3) attenuates interleukin-6 (IL-6)-induced collagen synthesis and resultant hypertrophy in rat heart

IL-6 has been shown to play a major role in collagen up-regulation process during cardiac hypertrophy, although the precise mechanism is still not known. In this study we have analyzed the mechanism by which IL-6 modulates cardiac hypertrophy. For the in vitro model, IL-6-treated cultured cardiac fibroblasts were used, whereas the in vivo cardiac hypertrophy model was generated by renal artery ligation in adult male Wistar rats (Rattus norvegicus). During induction of hypertrophy, increased phosphorylation of STAT1, STAT3, MAPK, and ERK proteins was observed both in vitro and in vivo. Treatment of fibroblasts with specific inhibitors for STAT1 (fludarabine, 50 μM), STAT3 (S31-201, 10 μM), p38 MAPK (SB203580, 10 μM), and ERK1/2 (U0126, 10 μM) resulted in down-regulation of IL-6-induced phosphorylation of specific proteins; however, only S31-201 and SB203580 inhibited collagen biosynthesis. In ligated rats in vivo, only STAT3 inhibitors resulted in significant decrease in collagen synthesis and hypertrophy markers such as atrial natriuretic factor and β-myosin heavy chain. In addition, decreased heart weight to body weight ratio and improved cardiac function as measured by echocardiography was evident in animals treated with STAT3 inhibitor or siRNA. Compared with IL-6 neutralization, more pronounced down-regulation of collagen synthesis and regression of hypertrophy was observed with STAT3 inhibition, suggesting that STAT3 is the major downstream signaling molecule and a potential therapeutic target for cardiac hypertrophy.

Amelioration of diabetes-induced cavernosal fibrosis by antioxidant and anti-transforming growth factor-β1 therapies in inducible nitric oxide synthase-deficient mice

OBJECTIVE

•  To investigate whether sustained long-term separate treatments of diabetic inducible nitric oxide synthase knockout (iNOSKo) mice with allopurinol, an antioxidant inhibiting xanthine oxidoreductase, decorin, a transforming growth factor-β1 (TGFβ1) -binding antagonist, and molsidomine, a long-life nitric oxide donor, prevent the processes of diabetes-induced cavernosal fibrosis.

MATERIALS AND METHODS

•  Eight week old male iNOS knock out (iNOSKo) mice were made diabetic by injecting 150 mg/kg B.W Streptozotocin (1P) with were either left untreated or treated with the oral antioxidant allopurinol (40 mg/kg/day), or decoin (50 mg, 1P, twice), as an anti-TGFβ1 agent (n = 8/group). •  Glycemia and oxidative stress markers were determined in blood and urine. •  Paraffin-embedded tissue sections from the penile shaft were subjected to Masson trichrome staining for the smooth muscle (smc)/collagen ratio, and imunostaining for smc content, profibrotic factors, oxidative stress, cell replication and cell death markers followed by quantitative image analysis.

RESULTS

•  Eight-week treatment with either allopurinol or decorin counteracted the decrease in smooth muscle cells and the increase in apoptosis and local oxidative stress within the corpora tissue. •  Decorin but not allopurinol increased the smooth muscle cell/collagen ratio, whereas allopurinol but not decorin inhibited systemic oxidative stress. •  Molsidomine was effective in reducing both local and systemic oxidative stress, but did not prevent corporal fibrosis.

CONCLUSION

•  Both allopurinol and decorin appear as promising approaches either as a single or a combined pharmacological modality for protecting the diabetic corpora from undergoing apoptosis and fibrosis although their functional effects still need to be defined.