Reno-protective effect of NECA in diabetic nephropathy: implication of IL-18 and ICAM-1

NECA alleviates inflammatory responses in diabetic retinopathy through dendritic cell toll-like receptor signaling pathway

Introduction

This study examined the impact of 5'-(N- ethylcarboxamido)adenosine (NECA) in the peripheral blood of healthy individuals, those with diabetes mellitus, diabetic retinopathy (DR), and C57BL/6 mice, both in vivo and in vitro.

Methods

Enzyme-linked immunosorbent assay (ELISA) and flow cytometry (FCM) were used to evaluate the effects of NECA on dendritic cells (DCs) and mouse bone marrow-derived dendritic cells (BMDCs) and the effects of NECA-treated DCs on Treg and Th17 cells. The effect of NECA on the Toll-like receptor (TLR) pathway in DCs was evaluated using polymerase chain reaction (PCR) and western blotting (WB).

Results

FCM and ELISA showed that NECA inhibited the expression of surface markers of DCs and BMDCs, increased anti-inflammatory cytokines and decreased proinflammatory cytokines. PCR and WB showed that NCEA decreased mRNA transcription and protein expression in the TLR-4-MyD88-NF-kβ pathway in DCs and BMDCs. The DR severity in streptozocin (STZ) induced diabetic mice was alleviated. NECA-treated DCs and BMDCs were co-cultivated with CD4+T cells, resulting in modulation of Treg and Th17 differentiation, along with cytokine secretion alterations.

Conclusion

NECA could impair DCs' ability to present antigens and mitigate the inflammatory response, thereby alleviating the severity of DR.

The diagnostic value of lipoprotein-associated phospholipase A2 in early diabetic nephropathy

OBJECTIVE

The aim of this study was to investigate diagnosis of lipoprotein-associated phospholipase A2 (Lp-PLA2) in early diabetic nephropathy (DN).

METHODS

A total of 342 type 2 diabetes mellitus (T2DM) patients hospitalized in department of metabolism and nephrology in our hospital from January 2019 to December 2019 were randomly selected. Patients were divided into three groups via urine albumin level: diabetes mellitus (DM) group, simple diabetes group (114 patients, urinary albumin creatinine ratio (UACR) < 30 mg/g); DN1 group, early DN group (114 patients, UACR: 30-300 mg/g); DN2 group: clinical DN group (114 patients, UACR > 300mg/g). Eighty healthy adults were examined at the same time. Lp-PLA2, fasting blood glucose (FBG), creatinine (Cr), triglyceride (TG), total cholesterol (TCHOL), high-density lipoprotein (HDL), low-density lipoprotein (LDL), haemoglobin A1c (HbA1c), blood urea nitrogen/creatinine (BUN/Cr), estimated glomerular filtration rate (eGFR), 24-h urine protein, albumin and creatinine of all subjects were detected and compared. Pearson's correlation analysis and multiple ordered logistic regression were used to investigate the correlation between serum Lp-PLA2 level and DN. The possibility of Lp-PLA2 in the diagnosis of early DN was studied by using the subject working curve.

RESULTS

Lp-PLA2 level in DN1 and DN2 groups was significantly higher than that in DM group, with statistical difference (p < .05). With the progression of DN, the level of Lp-PLA2 gradually increased p < .05. Lp-PLA2 was positively correlated with FBG, TG, LDL and HbA1c (R = 0.637, p < .01; R = 0.314, p = .01; R = 0.213, p = .01; R = 0.661, p ≤ .01), was negatively correlated with HDL (r = -0.230, p < .01). The results showed that Lp-PLA2 was an independent factor in the evaluation of early DN. The area under the curve for the evaluation of serum Lp-PLA2 level in early DN was 0.841, the optimal critical value was 155.9 ng/mL, the sensitivity was 88% and the specificity was 76.2%.

CONCLUSIONS

Lp-PLA2 is an independent factor for the evaluation of early DN, and can be used as an important potential specific indicator for the diagnosis of early DN, meanwhile monitoring the progression of DN.

TLR9 regulates NLRP3 inflammasome activation via the NF-kB signaling pathway in diabetic nephropathy

BACKGROUND

Toll-like receptors (TLRs) are critical sensors for the conservation of bacterial molecules and play a key role in host defense against pathogens. The effect of TLRs on the maintenance of diabetic nephropathy (DN) and resistance to infection has been investigated; however, the detailed effects of TLR9 on DN development remain elusive.

METHODS

We performed quantitative reverse transcription-polymerase chain reaction and western blotting to detect TLR9 expression levels in the kidneys of experimental mice (db/db) and high-glucose-treated mouse mesangial cell strains (MCs).

RESULTS

TLR9 expression was found to be remarkably upregulated in the kidneys of experimental mice (db/db) and MCs cultivated under hyperglycemic conditions. Moreover, knockdown of TLR9 could restrain NF-kB viability and downregulate the NLRP3 inflammasome in high glucose-treated MCs. TLR9 inhibition also alleviated inflammation and apoptosis, which was reversed by the addition of the NF-κB activator, betulinic acid. Furthermore, depleted TLR9 levels restrained NF-κB viability and NLRP3 expression and reduced kidney inflammation, microalbuminuria discharge, blood sugar level, and glomerular damage in experimental mice (db/db) kidneys. Conclusions These findings offer novel insights into the regulation of TLR9 via the nuclear factor-kB/NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome inflammation pathways in DN progression.

Diabetes Affects the A1 Adenosine Receptor-Dependent Action of Diadenosine Tetraphosphate (Ap4A) on Cortical and Medullary Renal Blood Flow

Diabetes through adenosine A1 receptor (A1R) and P2 receptors (P2Rs) may lead to disturbances in renal microvasculature. We investigated the renal microvascular response to Ap4A, an agonist of P2Rs, in streptozotocin-induced diabetic rats. Using laser Doppler flowmetry, renal blood perfusion (RBP) was measured during infusion of Ap4A alone or in the presence of A1R antagonist, either DPCPX (8-cyclopentyl-1,3-dipropylxanthine) or 8-cyclopentyltheophylline (CPT). Ap4A induced a biphasic response in RBP: a phase of rapid decrease was followed by a rapid increase, which was transient in diabetic rats but extended for 30 min in nondiabetic rats. Phase of decreased RBP was not affected by DPCPX or CPT in either group. Early and extended increases in RBP were prevented by DPCPX and CPT in nondiabetic rats, while in diabetic rats, the early increase in RBP was not affected by these antagonists. A1R mRNA and protein levels were increased in isolated glomeruli of diabetic rats, but no changes were detected in P2Y1R and P2Y2R mRNA. Presence of unblocked A1R is a prerequisite for the P2R-mediated relaxing effect of Ap4A in nondiabetic conditions, but influence of A1R on P2R-mediated renal vasorelaxation is abolished under diabetic conditions.

5-N-ethyl Carboxamidoadenosine Stimulates Adenosine-2b Receptor-Mediated Mitogen-Activated Protein Kinase Pathway to Improve Brain Mitochondrial Function in Amyloid Beta-Induced Cognitive Deficit Mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with loss in memory as one of the cardinal features. 5-N-ethyl carboxamidoadenosine (NECA), an agonist of adenosine-2b receptor, exerts neuroprotective activity against several experimental conditions. Further, NECA activates mitogen-activated protein kinase (MAPK) and also attenuates mitochondrial toxicity in mammalian tissues other than brain. Moreover, there is no report on the role of A2b/MAPK-mediated signaling pathway in Aβ-induced mitochondrial toxicity in the brain of the experimental animals. Therefore, the present study evaluated the neuroprotective activity of NECA with or without MAPK inhibitor against Aβ-induced cognitive deficit and mitochondrial toxicity in the experimental rodents. Further, the effect of NECA with or without MAPK inhibitor was evaluated on Aβ-induced mitochondrial toxicity in the memory-sensitive mice brain regions. Intracerebroventricular (ICV) injection of Aβ 1-42 was injected to healthy male mice through Hamilton syringe via polyethylene tube to induce AD-like behavioral manifestations. NECA attenuated Aβ-induced cognitive impairments in the rodents. In addition, NECA ameliorated Aβ-induced Aβ accumulation and cholinergic dysfunction in the selected memory-sensitive mouse HIP, PFC, and AMY. Further, NECA significantly attenuated Aβ-induced mitochondrial toxicity in terms of decrease in the mitochondrial function, integrity, and bioenergetics in the brain regions of these animals. However, MAPKI diminished the therapeutic effects of NECA on behavioral, biochemical, and molecular observations in AD-like animals. Therefore, it can be speculated that NECA exhibits neuroprotective activity perhaps through MAPK activation in AD-like rodents. Moreover, A2b-mediated MAPK activation could be a promising target in the management of AD.

Alteration of purinergic signaling in diabetes: Focus on vascular function

Diabetes is an important risk factor for the development of cardiovascular disease including atherosclerosis and ischemic heart disease. Vascular complications including macro- and micro-vascular dysfunction are the leading causes of morbidity and mortality in diabetes. Disease mechanisms at present are unclear and no ideal therapies are available, which urgently calls for the identification of novel therapeutic targets/agents. An altered nucleotide- and nucleoside-mediated purinergic signaling has been implicated to cause diabetes-associated vascular dysfunction in major organs. Alteration of both purinergic P1 and P2 receptor sensitivity rather than the changes in receptor expression accounts for vascular dysfunction in diabetes. Activation of P2X₇ receptors plays a crucial role in diabetes-induced retinal microvascular dysfunction. Recent findings have revealed that both ecto-nucleotidase CD39, a key enzyme hydrolyzing ATP, and CD73, an enzyme regulating adenosine turnover, are involved in the renal vascular injury in diabetes. Interestingly, erythrocyte dysfunction in diabetes by decreasing ATP release in response to physiological stimuli may serve as an important trigger to induce vascular dysfunction. Nucleot(s)ide-mediated purinergic activation also exerts long-term actions including inflammatory and atherogenic effects in hyperglycemic and diabetic conditions. This review highlights the current knowledge regarding the altered nucleot(s)ide-mediated purinergic signaling as an important disease mechanism for the diabetes-associated vascular complications. Better understanding the role of key receptor-mediated signaling in diabetes will provide more insights into their potential as targets for the treatment.

Interleukin-18 and diabetic nephropathy: A review

The inflammatory response has an important role in the pathophysiology of diabetic nephropathy that is contributed to by inflammatory mediators such as interleukin-1 (IL-1), IL-6, IL-18, tumor necrosis factor-α, and macrophage chemotactic protein-1; however, the role of IL-18 seems to be more specific than other cytokines in the inflammatory process. IL-18 is expressed in renal tissue and is upregulated by several stimuli including hyperglycemia. The expression/urinary level of IL-18 is positively correlated with the progression of diabetic nephropathy and the urinary albumin excretion rate. In this review, we have focused on the molecular pathways modulating the relationship between IL-18 and diabetic nephropathy.

Association between E469K polymorphism in the ICAM1 gene and the risk of diabetic nephropathy: a meta-analysis

BACKGROUND

Inflammation may be a key pathophysiological mechanism in diabetic nephropathy (DN). Intercellular adhesion molecule 1 (ICAM1) is an acute phase marker of inflammation. ICAM1 rs5498 has been reported to be associated with the risk of DN. However, the previous findings were conflicting due to the limited sample sizes, different methodologies and ethnicities. Therefore, this study aimed to investigate the genetic association between ICAM1 rs5498 and the risk of DN.

METHODS

Two investigators independently searched the studies from the databases PubMed, Web of Science, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and Embase. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the associations.

RESULTS

No significant association was detected between ICAM1 rs5498 and DN susceptibility in allelic and recessive models (p > 0.05). However, significant reduction of frequencies of the dominant model of ICAM1 rs5498 was only detected in the Caucasian subgroup (OR = 0.80; 95% CI = [0.65, 0.99], p = 0.04) and type 1 diabetes mellitus subgroup (OR = 0.80; 95% CI = [0.65, 0.99], p = 0.04).

CONCLUSIONS

Thus, ICAM1 rs5498 might be a risk factor for DN in Caucasians and type 1 diabetes mellitus patients, which suggested that ICAM1 rs5498 might help in early diagnosis and prevention of this disease. Further studies were needed to clarify the biochemical function and pathological role of ICAM1 rs5498 in the risk of DN.

miR-451 suppresses the NF-kappaB-mediated proinflammatory molecules expression through inhibiting LMP7 in diabetic nephropathy

Activation of nuclear factor -kappa B (NF-κB) is associated with inflammation in the progression of diabetic nephropathy (DN). MiR-451 is closely linked to renal damage in DN. Large multifunctional protease 7 (LMP7), an immunoproteasome subunit, can activate NF-κB. However, it remained unclear whether miR-451 affected NF-κB-induced inflammation by regulating LMP7 in DN. In this study, deep sequencing, in situ hybridization, quantitative real-time PCR, dual-luciferase reporter gene assays, western blot and chromatin immunoprecipitation were respectively used. For the results, we found that miR-451 was markedly downregulated in the kidneys of db/db mice, PBMCs of DN patients and mesangial cells (MCs) cultured in high glucose conditions. Furthermore, miR-451 directly targeted LMP7 expression to inhibit NF-κB activity, and down-regulated transcription of proinflammatory molecules in MCs. More importantly, in the kidneys of db/db DN mice, increasing miR-451 level inhibited LMP7/NF-κB activity, and attenuated the urinary microalbumin excretion, blood glucose, and glomerular injury. In conclusion, these results provide new insights into the regulation of miR-451 via the LMP7/NF-κB central inflammatory pathway during progression of DN.

Renoprotective effects of berberine and its potential effect on the expression of β-arrestins and intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in streptozocin-diabetic nephropathy rats

BACKGROUND

Berberine has been shown to exert protective effects against diabetic nephropathy (DN), but the mechanisms involved have not been fully characterized. The aim of the present study was to explore the effects of berberine on the expression of β-arrestins, intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in DN rat kidneys and investigate the underlying molecular mechanisms.

METHODS

To create the DN model, rats fed a high-fat and high-glucose diet were injected with a single dose of streptozotocin (35 mg/kg, i.p.). Then, DN rats were either treated or not with berberine (50, 100, 200 mg/kg per day, i.g., 8 weeks). Periodic acid-Schiff staining was used to evaluate renal histopathological changes. Renal tissue levels of β-arrestin 1 and β-arrestin 2 were determined by Western blot analysis, whereas immunohistochemistry was used to determine renal ICAM-1 and VCAM-1 levels.

RESULTS

Berberine (100, 200 mg/kg) ameliorated the histopathological changes in the diabetic kidney. Western blot analysis revealed significant increases in ICAM-1 and VCAM-1 levels in the kidneys of DN rats, which were reversed by treatment with 100 and 200 mg/kg berberine. In addition, berberine treatment (50, 100, 200 mg/kg) increased diabetic-induced decreases in β-arrestin 1 and β-arrestin 2.

CONCLUSIONS

Berberine exhibited renoprotective effects in DN rats. The underlying molecular mechanisms may be associated with changes in the levels and regulation of β-arrestin expression, as well as ICAM-1 and VCAM-1 levels in the rat kidney.

Cepharanthine and Piperine ameliorate diabetic nephropathy in rats: role of NF-κB and NLRP3 inflammasome

AIMS

Hyperglycemia leads to elevation of oxidative stress and proinflammatory cytokines which are the main causes of diabetic nephropathy (DN). NLRP3 inflammasome and thioredoxin-interacting protein (TXNIP) are recently assumed to participate in the development of DN. We aimed to investigate the effects of Cepharanthine (CEP), Piperine (Pip) and their combination in streptozotocin (STZ)-induced DN focusing on their role to modulate NLRP3 and TXNIP induced inflammation.

MAIN METHODS

Diabetic rats were treated with intraperitoneal (i.p.) injection of CEP (10mg/kg/day), Pip (30mg/kg/day) or their combination for 8weeks. Nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) were assessed by ELISA technique. TXNIP and NLRP3 genes expressions were evaluated by real time-PCR.

KEY FINDINGS

Diabetic rats showed significant increase in renal TXNIP and NLRP3 expression. CEP, Pip or their combination significantly decreased TXNIP and NLRP3 expression in diabetic kidneys. Hyperglycemia induced NF-κB activation leading to increased IL-1β and TNF-α levels. CEP, Pip or their combination showed significant inhibition of NF-κB together with decreased IL-1β and TNF-α levels in diabetic rats. Also, diabetic rats showed significant decrease in creatinine clearance and increase in blood glucose, serum creatinine, blood urea nitrogen, malondialdehyde, proteinuria, and kidney weight to body Weight ratio. All of these changes were reversed by CEP, Pip or their combination.

SIGNIFICANCE

The antioxidant and anti-inflammatory effects of CEP and Pip which were accompanied by inhibition of NF-κB and NLRP3 activation might be helpful mechanisms to halt the progression of DN.

The role of IL-18 in type 1 diabetic nephropathy: The problem and future treatment

Diabetic vascular complication is a leading cause of diabetic nephropathy, a progressive increase in urinary albumin excretion coupled with elevated blood pressure leading to declined glomerular filtration and eventually end stage renal failure. There is growing evidence that activated inflammation is contributing factor to the pathogenesis of diabetic nephropathy. Meanwhile, IL-18, a member of the IL-1 family of inflammatory cytokines, is involved in the development and progression of diabetic nephropathy. However, the benefits derived from the current therapeutics for diabetic nephropathy strategies still provide imperfect protection against renal progression. This imperfection points to the need for newer therapeutic agents that have potential to affect primary mechanisms contributing to the pathogenesis of diabetic nephropathy. Therefore, the recognition of IL-18 as significant pathogenic mediators in diabetic nephropathy leaves open the possibility of new potential therapeutic targets.

Amelioration of experimentally induced diabetic nephropathy and renal damage by nilotinib

Diabetes mellitus is an ever growing world-wide health problem. The patient has to stick to a firm life-long therapeutic regimen, otherwise diabetic complications will develop. Diabetic nephropathy (DN) is one of the most common diabetic complications and it requires careful medical attendance. Nilotinib hydrochloride is a protein tyrosine kinase inhibitor reported to have numerous therapeutic efficacies besides being an anticancer. In the current study, single I.P. streptozotocin (50 mg/kg) injection was used to induce type I diabetes mellitus in male Sprague-Dawley rats. After 8 weeks, significant deterioration of renal function with urinary excretion of nephrin, podocalyxin, and albumin was observed. Daily oral administration of nilotinib (20 mg/kg) for 8 weeks significantly improved signs of DN on all investigated scales. On a biochemical scale, kidney functions, albuminuria, urinary nephrin, podocalyxin excretion, and host oxidant/antioxidant balance significantly improved. Kidney content of nitric oxide, expression of toll-like receptors 4 and NF-κB/p65 activity significantly declined as well. On a histopathological scale, α-smooth muscle actin and nestin expression significantly declined. Meanwhile, area of fibrosis significantly declined as seen with significant reduction in accumulation of extracellular matrix components and kidney content of collagen. Ultimately, such improvements were accompanied by significant restoration of normal kidney physiology and function. In conclusion, nilotinib can hinder progression of DN through various mechanisms. Reduction of oxidative stress, enhancement of host antioxidant defense system, reduction of inflammation, angiogenesis, tissue hypoxia, and pro-fibrogenic biomarker expression can be implicated in the beneficial therapeutic outcome observed with nilotinib therapy.

Thymoquinone attenuates Doxorubicin-induced nephrotoxicity in rats: Role of Nrf2 and NOX4

Doxorubicin (DOX) is a chemotherapeutic drug widely used for the treatment of various neoplastic conditions. However, its application is limited because of its toxic effects in many organs. Nephrotoxicity is a serious effect of DOX. The aim of this study was to determine the protective effect of thymoquinone (TQ), a predominant bioactive constituent of Nigella sativa oil, with well documented potent anti-oxidative and anti-inflammatory effects. Male Sprague Dawley rats received DOX (3.5mg/kg twice weekly) with or without TQ (50mg/kg/day, oral supplementation) for 3weeks. Elevated levels of serum urea, creatinine and urinary albumin excretion were observed in DOX-treated animals, indicating DOX-induced nephrotoxicity. Moreover, enhanced lipid peroxidation (LPO), as equivalents of malondialdehyde (MDA), in the renal tissue was accompanied by a significant decrease in the activities of superoxide dismutase (SOD) and glutathione-S-transferase (GST) in DOX-treated group. In addition, DOX treatment induced significant increase in renal levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and NADPH oxidase 4 (NOX-4), and marked decrease in interleukin-10 (IL-10) levels, nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA levels and nuclear binding activity. Histopathological analysis showed severe damage in the renal tissue of DOX treated animals. Animals treated with TQ were found to have markedly reduced renal damage with restoration of all mentioned markers toward normal values. In conclusion, DOX-induced renal damage involved a redox imbalance in renal tissue, which could be reversed by TQ, suggesting a possible potential role for TQ in DOX-induced nephrotoxicity.

Cod liver oil in sodium nitrite induced hepatic injury: does it have a potential protective effect?

OBJECTIVES

Exposure to sodium nitrites, a food additive, at high levels has been reported to produce reactive nitrogen and oxygen species that cause dysregulation of inflammatory responses and tissue injury. In this work, we examined the impact of dietary cod liver oil on sodium nitrite-induced inflammation in rats.

METHODS

Thirty-two adult male Sprague-Dawely rats were treated with 80 mg/kg sodium nitrite in presence/absence of 5 ml/kg cod liver oil. Liver sections were stained with hematoxylin/eosin. We measured hepatic tumor necrosis factor (TNF)-α, interleukin-1 beta (IL)-1β, C-reactive protein (CRP), transforming growth factor (TGF)-β1, and caspase-3.

RESULTS

Cod liver oil reduced sodium nitrite-induced hepatocyte damage. In addition, cod liver oil results in reduction of hepatic TNF-α, IL-1β, CRP, TGF-β1, and caspase-3 when compared with the sodium nitrite group.

DISCUSSION

Cod liver oil ameliorates sodium nitrite-induced hepatic injury via multiple mechanisms including blocking sodium nitrite-induced elevation of inflammatory cytokines, fibrosis mediators, and apoptosis markers.

Purinergic signalling in the kidney in health and disease

The involvement of purinergic signalling in kidney physiology and pathophysiology is rapidly gaining recognition and this is a comprehensive review of early and recent publications in the field. Purinergic signalling involvement is described in several important intrarenal regulatory mechanisms, including tuboglomerular feedback, the autoregulatory response of the glomerular and extraglomerular microcirculation and the control of renin release. Furthermore, purinergic signalling influences water and electrolyte transport in all segments of the renal tubule. Reports about purine- and pyrimidine-mediated actions in diseases of the kidney, including polycystic kidney disease, nephritis, diabetes, hypertension and nephrotoxicant injury are covered and possible purinergic therapeutic strategies discussed.

Activation of adenosine receptors improves renal antioxidant status in diabetic Wistar but not SHR rats

BACKGROUND

Diabetes and hypertension independently contribute to renal injury, and the major mechanisms involved are increased reactive oxygen species (ROS) bioavailability and renin-angiotensin system (RAS) activation. We investigated the role of adenosine in controlling ROS production and RAS activation associated with renal dysfunction in hypertension and diabetes.

METHODS

Fourteen days after induction of diabetes with streptozotocin in 12-week-old male Wistar and spontaneously hypertensive (SHR) rats, animals were treated during 7 days with 2-chloroadenosine (CADO group, 5 mg/kg/d), a stable analogue of adenosine, or underwent a sham operation procedure. At the end of the study (day 21), intra-arterial systolic blood pressure (SBP) was measured, and 24-h urine and plasma samples and renal tissue were collected.

RESULTS

CADO treatment decreased the plasma glucose concentration and glucose and protein excretion by more than 30% in both strains. CADO treatment decreased SBP in diabetic SHR rats (143 ± 8 versus 114 ± 4 mmHg, p < 0.05), but not in diabetic Wistar rats. The hypotensive effect of CADO was associated to a ∼70% increase in plasma angiotensinogen (AGT) concentration and a ∼50% decrease in urinary AGT excretion. CADO also caused a decrease in medullary and cortical hydrogen peroxide production of about 40%, which was associated with a proportional increase in glutathione peroxidase (GPx) activity in diabetic Wistar but not in diabetic SHR animals.

CONCLUSIONS

These results suggest that activation of adenosine receptors improves renal antioxidant capacity in diabetic Wistar but not SHR rats, although it improves glucose metabolism in both strains. Furthermore, activation of adenosine receptors does not seem to be directly influencing AGT production.