Protective effects of captopril in diabetic rats exposed to ischemia/reperfusion renal injury

Alpha-cyperone mitigates renal ischemic injury via modulation of HDAC-2 expression in diabetes: Insights from molecular dynamics simulations and experimental evaluation

Chronic diabetes mellitus is reported to be associated with acute kidney injury. The enzyme histone deacetylase-2 (HDAC-2) was found to be upregulated in diabetes-related kidney damage. Alpha-cyperone (α-CYP) is one of the active ingredients of Cyperus rotundus that possesses antioxidant and anti-inflammatory effects. We evaluated the effect of α-CYP on improving oxidative stress and tissue inflammation following renal ischemia/reperfusion (I/R) injury in diabetic rats. The effect of α-CYP on HDAC-2 expression in renal homogenates and in the NRK-52 E cell line was evaluated following renal I/R injury and high glucose conditions, respectively. Molecular docking was used to investigate the binding of α-CYP with the HDAC-2 active site. Both renal function and oxidative stress were shown to be impaired in diabetic rats due to renal I/R injury. Significant improvements in kidney/body weight ratio, creatinine clearance, serum creatinine, blood urea nitrogen (BUN), and uric acid were observed in diabetic rats treated with α-CYP (50 mg/kg) two weeks prior to renal I/R injury. α-CYP treatment also improved histological alterations in renal tissue and lowered levels of malondialdehyde, myeloperoxidase, and hydroxyproline. Treatment with α-CYP suppressed the increased HDAC-2 expression in the renal tissue of diabetic rats and in the NRK-52 E cell line. The molecular docking reveals that α-CYP binds to HDAC-2 with good affinity, ascertained by molecular dynamics simulations and binding free energy analysis. Overall, our data suggest that α-CYP can effectively prevent renal injury in diabetic rats by regulating oxidative stress, tissue inflammation, fibrosis and inhibiting HDAC-2 activity.

Investigation of the Captopril-Insulin Interaction by Mass Spectrometry and Computational Approaches Reveals that Captopril Induces Structural Changes in Insulin

Post-translational modifications remarkably regulate proteins' biological function. Small molecules such as reactive thiols, metabolites, and drugs may covalently modify the proteins and cause structural changes. This study reports the covalent modification and noncovalent interaction of insulin and captopril, an FDA-approved antihypertensive drug, through mass spectrometric and computation-based approaches. Mass spectrometric analysis shows that captopril modifies intact insulin, reduces it into its "A" and "B" chains, and covalently modifies them by forming adducts. Since captopril has a reactive thiol group, it might reduce the insulin dimer or modify it by reacting with cysteine residues. This was proven with dithiothreitol treatment, which reduced the abundance of captopril adducts of insulin A and B chains and intact Insulin. Liquid chromatography tandem mass spectrometric analysis identified the modification of a total of four cysteine residues, two in each of the A and B chains of insulin. These modifications were identified to be Cys6 and Cys7 of the A chain and Cys7 and Cys19 of the B chain. Mass spectrometric analysis indicated that captopril may simultaneously modify the cysteine residues of intact insulin or its subunits A and B chains. Biophysical studies involving light scattering and thioflavin T assay suggested that the binding of captopril to the protein leads to the formation of aggregates. Docking and molecular dynamics studies provided insights into the noncovalent interactions and associated structural changes in insulin. This work is a maiden attempt to understand the detailed molecular interactions between captopril and insulin. These findings suggest that further investigations are required to understand the long-term effect of drugs like captopril.

Captopril Combined with Furosemide or Hydrochlorothiazide Affects Macrophage Functions in Mouse Contact Hypersensitivity Response

Hypertension is a chronic disease associated with chronic inflammation involving activated macrophages. Antihypertensive drugs (for example, angiotensin-converting enzyme inhibitors—ACEIs) used in the treatment of hypertension have immunomodulatory properties. On the other hand, the immunological effect of diuretics and combined drugs (diuretics + ACEI) is unclear. Therefore, we examined the influence of diuretics and combination drugs (ACEI + diuretic) on cellular response (contact hypersensitivity), production of reactive oxygen intermediates (ROIs), and nitric oxide (NO), and the secretion of interleukin-12 (IL-12). CBA mice were administered i.p. captopril (5 mg/kg) with or without hydrochlorothiazide (10 mg/kg) or furosemide (5 mg/kg) for 8 days. On the third day, the mice were administered i.p. mineral oil, and macrophages were collected 5 days later. In the presented results, we show that diuretics administered alone or with captopril increase the generation of ROIs and reduce the formation of NO by macrophages. Moreover, tested drugs inhibit the secretion of IL-12. Diuretics and combined drugs reduce the activity of contact hypersensitivity (both activation and induction phases). Our research shows that the tested drugs modulate the cellular response by influencing the function of macrophages, which is important in assessing the safety of antihypertensive therapy.

The angiotensin-converting enzyme inhibitor, captopril, suppressed hepatic stellate cell activation via NF-kappaB or wnt3α/β-catenin pathway

Activation of hepatic stellate cells (HSC) is associated with hepatic fibrogenesis, which is one of complications of diabetes mellitus. Captopril possesses potent anti-inflammation, oxidative stress and fibrosis effects. However, the specific molecular mechanism of captopril in high glucose (HG)-induced hepatic stellate cells has not been elucidated. Following the treatment of HG or captopril treatment for rat hepatic stellate cells (HSC-T6), cell activities were detected by Cell Counting Kit-8 (CCK8) assay. Reactive oxygen species (ROS) levels were determined by ROS staining. The expression of inflammation-related proteins (Interleukin (IL)-1β, IL-6 and IL-8) and fibrosis-related proteins (fibronectin (FN), collagen I, collagen III, collagen IV, matrix metallopeptidase (MMP-2 and MMP-9) were determined by Western blot. Captopril significantly decreased HSC-T6 cell viability induced by HG in a dose-dependent manner, as well as decreased levels of malondialdehyde (MDA), ROS, pro-inflammatory markers and fibrosis-related proteins, while upregulated superoxide dismutase (SOD) activities. We further found that captopril decreased the ratio of p-IκBα/IκBα and the ratio of p-p65/p65. Intriguing, phorbol myristate acetate (PMA) or LiCl was able to significantly reverse the captopril-induced alteration of oxidative stress-, inflammation- and fibrosis-marker levels. In conclusion, in HG-stimulated HSC-T6 cells, captopril displayed a potent ability to inhibit oxidative stress, inflammation and hepatic fibrogenesis via NF-kappaB or wnt3α/β-catenin. These results demonstrated the mechanism of captopril as well as the role of the NF-kappaB or wnt3α/β-catenin on HSC-T6 activation induced by HG.

Role of Oxidative Stress and Reduced Endogenous Hydrogen Sulfide in Diabetic Nephropathy

Purpose

Persistent hyperglycemia lead towards depletion of hydrogen sulfide (H₂S) resulting in generation of oxidative stress and diabetic nephropathy. The aim of the current study was to explore the antioxidant potential of H₂S and captopril, a -SH containing compound in streptozotocin (STZ)-induced diabetic nephropathy.

Methods

Fifty four Wistar-Kyoto (WKY) rats male (200-250g) were divided into nine groups (n=6) with each group injected once with STZ (60mg/kg i.p) except normal control. After 3 weeks of induction of diabetes, groups were assigned as normal control, diabetic control, diabetic-captopril, diabetic-NaHS, diabetic-captopril-NaHS, diabetic-spironolactone, diabetic-metformin, diabetic-metformin-NaHS and diabetic-vitamin-c. All the animals were served with normal saline (N/S 4mL/kg p.o), captopril (50mg/kg/day p.o), sodium hydrosulfide (NaHS) (56µmol/kg i.p), spironolactone (50mg/kg/day s.c), metformin (500mg/kg/day p.o) and vitamin-c (50mg/kg p.o) on daily basis for next 4 weeks, respectively. Metabolic studies, H₂S levels, renal hemodynamics and oxidative stress markers were analyzed at 0, 14 and 28 days followed by histopathological analysis of renal tissues.

Results

The results showed decreased H₂S levels, body weight, sodium to potassium ratio, glutathione (GSH), superoxide dismutase (SOD), total antioxidant assay (T-AOC) with malondialdehyde (MDA) and blood glucose levels significantly increased among diabetic rats. Treatment with captopril, NaHS, metformin, spironolactone and vitamin C showed significant improvement among renal hemodynamics and oxidative stress markers, respectively. But treatment groups like NaHS in combination with captopril and metformin showed more pronounced effects.

Conclusion

The observations suggest that H₂S mediated protective effects on STZ-induced diabetic nephropathy may be associated with reduced oxidative stress via augmenting the antioxidant effect.

Aliskiren and captopril improve cognitive deficits in poorly controlled STZ-induced diabetic rats via amelioration of the hippocampal P-ERK, GSK3β, P-GSK3β pathway

Learning and memory deficits are obvious symptoms that develop over time in patients with poorly controlled diabetes. Hyperactivity of the renin-angiotensin system (RAS) is directly associated with β-cell dysfunction and diabetic complications, including cognitive impairment. Here, we investigated the protective and molecular effects of two RAS modifiers, aliskiren; renin inhibitor and captopril; angiotensin converting enzyme inhibitor, on cognitive deficits in the rat hippocampus. Injection of low dose streptozotocin for 4 days resulted in type 1 diabetes. Then, poorly controlled diabetes was mimicked with ineffective daily doses of insulin for 4 weeks. The hyperglycaemia and pancreatic atrophy caused memory disturbance that were identifiable in behavioural tests, hippocampal neurodegeneration, and the following significant changes in the hippocampus, increases in the inflammatory marker interleukin 1β, cholinesterase, the oxidative stress marker malondialdehyde and protein expression of phosphorylated extracellular-signal-regulated kinase and glycogen synthase kinase-3 beta versus decrease in the antioxidant reduced glutathione and protein expression of phosphorylated glycogen synthase kinase-3 beta. Blocking RAS with either drugs along with insulin amended all previously mentioned parameters. Aliskiren stabilized the blood glucose level and restored normal pancreatic integrity and hippocampal malondialdehyde level. Aliskiren showed superior protection against the hippocampal degeneration displayed in the earlier behavioural modification in the passive avoidance test, and the aliskiren group outperformed the control group in the novel object recognition test. We therefore conclude that aliskiren and captopril reversed the diabetic state and cognitive deficits in rats with poorly controlled STZ-induced diabetes through reducing oxidative stress and inflammation and modulating protein expression.

Pterostilbene administration improves the recovery potential of extremely low-frequency magnetic field in acute renal ischemia-reperfusion injury: an FTIR spectroscopic study

Renal ischemia-reperfusion (I/R) injury, one of the drastic outcomes of renal failure and organ transplantation, tends to deteriorate over time; therefore, noninvasive therapeutic strategies will avail the progression-free survival of the patients. Magnetic field has been proposed as a noninvasive treatment strategy; however, with recent scientific advances, many controversies have arisen regarding its efficacy. Pterostilbene, a natural analog of resveratrol, was documented to be effective in treatment of I/R injuries. This study aims to assess the acute therapeutic effects of combined extremely low-frequency magnetic field (ELF-MF) and pterostilbene treatment on renal I/R injury. After induction of renal I/R in Wistar rats, treatments of 50 Hz, 1 mT ELF-MF applied alone or in combination with pterostilbene were applied for 5 consecutive days. Kidney homogenates were analyzed by Fourier transform infrared spectroscopy. I/R injury resulted in an altered protein and lipid structure with the dominance of longer acyl chains; a slight decrease in lipid, protein, unsaturated lipid, and unsaturated/saturated lipid content; and an increase in membrane fluidity and lipid peroxidation in rat kidneys. Although ELF-MF treatment alone was not sufficient to restore all ischemia-induced alterations, the combined treatment strategy of pterostilbene administration in the presence of ELF-MF was successful and warrants further investigation.

Activation of Nrf2 Signaling by Apelin Attenuates Renal Ischemia Reperfusion Injury in Diabetic Rats

OBJECTIVE

Renal ischemia/reperfusion (I/R) injury is commonly seen in diabetic patients. Apelin has been demonstrated to protect against renal I/R injury, whereas detailed modulatory mechanisms by which Apelin exerts its role in renal I/R injury in diabetic patients remain unclarified. This research aimed to probe the functional molecules under the regulation of Apelin in renal I/R injury in diabetic rats.

MATERIALS AND METHODS

First, animal models were established for subsequent assays. Biochemical kits measured the serum levels of blood urea nitrogen (BUN) and serum creatinine (SCR), and hematoxylin and eosin (H&E) staining examined the histopathological changes of kidney tissues. Inflammatory factors containing tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) were tested through enzyme-linked immunosorbent assay (ELISA) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), respectively. Reactive oxygen species (ROS) levels in the serum and kidney tissues were separately assessed by specific ROS kits. Cell apoptosis was further estimated through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and Western blot analysis. Eventually, the influences of Apelin on nuclear factor erythroid 2-related factor (Nrf2) and its downstream genes were explored via Western blot analysis and immunohistochemistry (IHC).

RESULTS

In the present study, Apelin ameliorated the damage to renal function and histological structure, decreased levels of inflammatory factors and ROS, and hampered cell apoptosis in renal I/R injury of diabetic rats. Moreover, Apelin could elevate the levels of Nrf2 and downstream genes which were decreased under renal I/R injury.

CONCLUSION

These data indicated that Apelin inhibited renal I/R injury through regulating Nrf2 signaling in diabetic rats, which might shed new light on the treatment of renal I/R injury in diabetic patients.

Effects of Dexmedetomidine on Renal Ischaemia Reperfusion Injury in Streptozotocin-Induced Diabetic Rats

Objective

The aim of this study was to investigate the effects of dexmedetomidine before and after ischaemia in diabetic rat kidney ischaemia reperfusion (IR) injury in the experimental diabetic rat model.

Methods

Data belonging to 35 rats weighing between 250 and 300 g were analysed. Diabetes mellitus (DM) was induced using streptozotocin. Groups had bilateral renal vasculature clamped for 45 min ischaemia before clamps were removed, and 4 hours reperfusion was applied. Rats were divided into five groups: Group I or nondiabetic sham group (n=7), Group II or diabetic sham group (n=7), Group III or diabetic IR group (n=7), Group IV or diabetic IR+prophylactic Dex P (before ischaemia) (n=7) and Group V or diabetic IR+therapeutic Dex T (following reperfusion) (n=7). Dexmedetomidine was administered at a dose of 100 μg kg^-1 intraperitoneally. Histomorphological and biochemical methods were used to assess the blood and tissue samples.

Results

The proximal tubule injury score in the control sham group was significantly lower than in other groups. The proximal tubule and total cell damage scores of the diabetic IR group were significantly higher than the diabetic IR+Dex T group, and no significant difference was detected in the diabetic IR+Dex P group. The biochemical parameters of the IR group were significantly increased compared to Groups I and II; however, there was no significant reduction in these parameters in the groups administered dexmedetomidine.

Conclusion

Although administration of dexmedetomidine after ischaemia in the diabetic rat renal IR model was found to be more effective on the histopathological injury scores compared to preischaemic administration, this study has not shown that dexmedetomidine provides effective and complete protection in DM.

Captopril alleviates hypertension-induced renal damage, inflammation, and NF-κB activation

Hypertensive renal damage generally occurs during the middle and late stages of hypertension, which is typically characterized by proteinuria and renal inflammation. Captopril, an angiotensin-converting enzyme (ACE) inhibitor, has been widely used for therapy of arterial hypertension and cardiovascular diseases. However, the protective effects of captopril on hypertension-induced organ damage remain elusive. The present study was designed to explore the renoprotective action of captopril in spontaneously hypertensive rats (SHR). The 6-week-old male SHR and age-matched Wistar-Kyoto rats were randomized into long-term captopril-treated (34 mg/kg) and vehicle-treated groups. The results showed that in SHR there was obvious renal injury characterized by the increased levels of urine albumin, total protein, serum creatinine, blood urea nitrogen, renal inflammation manifested by the increased mRNA and protein expression of inflammatory factors including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and inducible nitric oxide synthase, and enhanced nuclear factor-κB (NF-κB) activation. Captopril treatment could lower blood pressure, improve renal injury, and suppress renal inflammation and NF-κB activation in SHR rats. In conclusion, captopril ameliorates renal injury and inflammation in SHR possibly via inactivation of NF-κB signaling.

YAP-mediated mechanotransduction determines the podocyte's response to damage

Podocytes are terminally differentiated cells of the kidney filtration barrier. They are subjected to physiological filtration pressure and considerable mechanical strain, which can be further increased in various kidney diseases. When injury causes cytoskeletal reorganization and morphological alterations of these cells, the filtration barrier may become compromised and allow proteins to leak into the urine (a condition called proteinuria). Using time-resolved proteomics, we showed that podocyte injury stimulated the activity of the transcriptional coactivator YAP and the expression of YAP target genes in a rat model of glomerular disease before the development of proteinuria. Although the activities of YAP and its ortholog TAZ are activated by mechanical stress in most cell types, injury reduced YAP and TAZ activity in cultured human and mouse podocyte cell lines grown on stiff substrates. Culturing these cells on soft matrix or inhibiting stress fiber formation recapitulated the damage-induced YAP up-regulation observed in vivo, indicating a mechanotransduction-dependent mechanism of YAP activation in podocytes. YAP overexpression in cultured podocytes increased the abundance of extracellular matrix-related proteins that can contribute to fibrosis. YAP activity was increased in mouse models of diabetic nephropathy, and the YAP target CTGF was highly expressed in renal biopsies from glomerular disease patients. Although overexpression of human YAP in mice induced mild proteinuria, pharmacological inhibition of the interaction between YAP and its partner TEAD in rats ameliorated glomerular disease and reduced damage-induced mechanosignaling in the glomeruli. Thus, perturbation of YAP-dependent mechanosignaling is a potential therapeutic target for treating some glomerular diseases.

Protective Effects of the Segmental Renal Artery Clamping Technique on Ischemia-Reperfusion Injury in db/db Diabetic Mice

Renal ischemia-reperfusion (I/R) injury is inevitable in partial nephrectomy and other kidney surgeries, with a higher incidence in patients with renal insufficiency. This study aimed to investigate the protective effects of precise segmental renal artery clamping (SRAC) against renal I/R injury in db/db diabetic mice, compared with conventional renal artery clamping (RAC). Grape seed extract, a powerful free radical scavenger, was administered to diabetic mice for 4 weeks before operation in subgroups (30 mg/kg/d). The unilateral renal pedicle was ligatured, and I/R injury to the contralateral kidney was induced (ischemia for 30 min followed by reperfusion for 24 h). Blood glucose value, creatinine, blood urea nitrogen, and urine microalbumin/urine creatinine ratio increased gradually and showed no preoperative statistical differences among six subgroups. These parameters were significantly lower in the SRAC than in the RAC group 24 h postoperatively. Moreover, the nonischemic area in the SRAC group expressed less KIM-1 and TNF-α mRNA and also revealed minor histopathological damage induced by I/R. These findings suggest that SRAC effectively reduces early renal injury induced by I/R and accelerates the recovery of renal function in diabetic mice. Thus, SRAC may be an ideal technique in partial nephrectomy, especially for patients with diabetic nephropathy and other renal insufficiencies.

Effects of captopril, telmisartan and bardoxolone methyl (CDDO-Me) in ischemia-reperfusion-induced acute kidney injury in rats: an experimental comparative study

Renal ischemia-reperfusion (IR) injury is one of the most common causes of acute kidney injury. This study investigated the effects of captopril (CAP), telmisartan (TEL) and bardoxolone methyl (BM) in animals with renal IR injury. Adult male Wistar-Albino rats were divided into six groups: control, vehicle, IR, IR with CAP, IR with TEL and IR with BM. Before IR was induced, drugs were administered by oral gavage. After a 60-min ischemia and a 120-min reperfusion period, bilateral nephrectomies were performed. Serum urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL) levels, tissue total oxidant status (TOS), total antioxidant status (TAS), total thiol (TT), asymmetric dimethylarginine (ADMA) levels, superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity were measured. Tissue mRNA expression levels of peroxisome proliferator-activated receptor-ɣ (PPAR-ɣ), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were analyzed. In addition, renal tissues were evaluated histopathologically and immunohistochemically. All tested drugs reduced renal damage, apoptosis, urea, creatinine, NGAL, TOS, nitric oxide (NO) and ADMA levels, NF-κB, inducible nitric oxide synthase (iNOS) and endothelin-1 (ET-1) expressions (P < 0.001). All tested drugs increased SOD activity, GSH-Px activity, TAS levels, TT levels, endothelial nitric oxide synthase (eNOS) expression, dimethylarginine dimethylaminohydrolases (DDAHs) expression, Nrf2 expression and PPAR-ɣ expression (P < 0.001, P < 0.003). These results suggest that CAP, TEL and BM pretreatment could reduce renal IR injury via anti-inflammatory, antioxidant and anti-apoptotic effects.

Possible Underlying Mechanisms of the Renoprotective Effect of Remote Limb Ischemic Preconditioning Against Renal Ischemia/Reperfusion Injury: A Role of Osteopontin, Transforming Growth Factor-Beta and Survivin

BACKGROUND

It has been documented that remote limb ischemic preconditioning (rIPC) protect kidneys against renal ischemia/reperfusion (I/R). We hypothesized that osteopontin (OPN), transforming growth factor beta (TGF-β), apoptotic proteins (survivin and caspase-3) and oxidative stress play role in the renoprotective effects of rIPC.

MATERIALS AND METHODS

Fifty-four male Sprague-Dawley rats were randomized into 3 equal groups: sham group, I/R group (left renal 45 min ischemia) and rIPC group (as I/R group with 3 cycles of left hind limb ischemia just before renal ischemia). Each group was subdivided into 24, 48 and 72 h groups according to the time of sacrifice. We measured serum creatinine and blood urea nitrogen (BUN) at the baseline and end points. Also, left kidney was harvested at study end points for assessment of the expression of OPN, TGF-β, apoptotic proteins (survivin and caspase-3) and oxidative stress markers (malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)) in kidney tissues and histopathological examination.

RESULTS

Serum creatinine and BUN levels and histopathological damage score were significantly lower in rIPC group than I/R group (p < 0.005). Also, compared to I/R group, the levels of MDA and the expression of OPN, TGF-β and caspase-3 in kidney tissues were significantly lower in rIPC group, while the levels of SOD and GSH and the expression of survivin in kidney tissues were significantly higher in rIPC group at all time points (p ≤ 0.05).

CONCLUSIONS

rIPC exhibited protective effects against renal I/R injury which might be due to inhibition of OPN expression, inflammatory cytokine TGF-β and caspase-3 and activation of anti-apoptotic protein survivin as well as improvement of oxidative stress in kidney tissues.

Overexpression of DJ-1 reduces oxidative stress and attenuates hypoxia/reoxygenation injury in NRK-52E cells exposed to high glucose

Patients with diabetes are more vulnerable to renal ischemia/reperfusion (I/R) injury, which is implicated in hyperglycemia-induced oxidative stress. We previously reported that the hyperglycemia-induced inhibition of DJ-1, a novel oncogene that exhibits potent antioxidant activity, is implicated in the severity of myocardial I/R injury. In the present study, we aimed to explore the role of DJ-1 in hypoxia/reoxygenation (H/R) injury in renal cells exposed to high glucose (HG). For this purpose, NRK-52E cells were exposed to HG (30 mM) for 48 h and then exposed to hypoxia for 4 h and reoxygenation for 2 h, which significantly decreased cell viability and superoxide dismutase (SOD) activity, and increased the malondialdehyde (MDA) content, accompanied by a decrease in DJ-1 protein expression. The overexpression of DJ-1 by transfection with a DJ-1 overexpression plasmid exerted protective effects against HG-induced H/R injury, as evidenced by increased CCK-8 levels and SOD activity, the decreased release of lactate dehydrogenase (LDH) and the decreased MDA content, and increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) expression. Similar effects were observed following treatment with the antioxidant, N-acetylcysteine. These results suggest that the overexpression of DJ-1 reduces oxidative stress and attenuates H/R injury in NRK-52E cells exposed to HG.

Effect of captopril and telmisartan on methotrexate-induced hepatotoxicity in rats: impact of oxidative stress, inflammation and apoptosis

Methotrexate (MTX) is a commonly used antineoplastic and anti-rheumatoid drug whose efficacy is limited by its hepatotoxicity. The aim of this study was to investigate the possible protective role of captopril (100 mg/kg/day, p.o. for seven days), an angiotensin converting enzyme inhibitor, and telmisartan (10 mg/kg/day p.o. for seven days), an angiotensin II receptor blocker with peroxisome proliferative receptor gamma (PPARγ) agonism, in a model of MTX (single dose 20 mg/kg i.p. at the fifth day) induced hepatotoxicity in rats. Results of the present study revealed MTX-induced hepatotoxicity as demonstrated by increased level of liver enzymes and confirmed by histopathology. Pretreatment with captopril or telmisartan produced a significant hepatic protection manifested as a significant (p < 0.05) decrease in serum levels of alanine transferase (ALT) and aspartate transferase (AST) and alkaline phosphatase (ALP) enzymes; hepatic malondialdehyde (MDA) and total nitrites and nitrates (NOx) levels; as well as a significant increase in hepatic superoxide dismutase (SOD) activity. In addition, there was a remarkable improvement in the histopathological features and a significant reduction in the expression of COX-2, iNOS and caspase-3 enzymes as compared with the MTX group. We recommend considering captopril/Telmisartan, if tolerated and not contraindicated, as preferable antihypertensive agents in patients receiving MTX in their chemotherapy protocols.

Renal Ischemia/Reperfusion Injury in Diabetic Rats: The Role of Local Ischemic Preconditioning

Background. The aim of this study was to evaluate the effects of local ischemic preconditioning using biochemical markers and histopathologically in the diabetic rat renal IR injury model. Methods. DM was induced using streptozotocin. Rats were divided into four groups: Group I, nondiabetic sham group (n = 7), Group II, diabetic sham group (n = 6), Group III, diabetic IR group (diabetic IR group, n = 6), and Group IV, diabetic IR + local ischemic preconditioning group (diabetic IR + LIPC group, n = 6). Ischemic renal injury was induced by clamping the bilateral renal artery for 45 min. 4 h following ischemia, clearance protocols were applied to assess biochemical markers and histopathologically in rat kidneys. Results. The histomorphologic total cell injury scores of the nondiabetic sham group were significantly lower than diabetic sham, diabetic IR, and diabetic IR + LIPC groups. Diabetic IR group scores were not significantly different than the diabetic sham group. But diabetic IR + LIPC group scores were significantly higher than the diabetic sham and diabetic IR groups. Conclusion. Local ischemic preconditioning does not reduce the risk of renal injury induced by ischemia/reperfusion in diabetic rat model.

Effects of Tulbaghia violacea Harv. (Alliaceae) rhizome methanolic extract on kidney function and morphology in Dahl salt-sensitive rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tulbaghia violacea has been used traditionally for the treatment of several ailments, including hypertension. The herb has been shown to have antihypertensive properties which have been attributed to its angiotensin-converting enzymeinhibitory (ACEI) activity. It could, therefore, prove beneficial in ameliorating renal pathology associated with hypertension. To evaluate the effects of long-term administration of Tulbaghia violacea on renal function and morphology in the Dahl salt-sensitive (DSS) rat model.

MATERIALS AND METHODS

Male DSS rats were treated intra-peritoneally (i.p.) as follows: methanolic extract of Tulbaghia violacea: (TVL) (50 mg/kg/b.w.), captopril: (CAP) (25 mg/kg/b.w.), or distilled water, control: (CON) (3 ml/kg/b.w.). Blood pressure (BP) was measured bi-weekly, whilst 24-h urine volumes and electrolyte concentrations were assessed weekly. Animals were sacrificed on day 49 by halothane overdose. Blood was removed for determination of plasma and serum electrolytes. Left kidney tissues were harvested for the determination of nuclear factor-kappaβ (NF-kβ) and transforming growth factor-β (TGF-β) gene expressions.

RESULTS

TVL significantly reduced mean arterial pressure (MAP) and diastolic blood pressure (DBP). TVL showed reduced blood urea nitrogen, serum creatinine, total protein in urine as well as increased serum total protein. TVL decreased thiobarbituric acid reactive substances (TBARS) and increased glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity and nitric oxide significantly. NF-kβ and TGF-β) gene expressions were significantly reduced in TVL and CAP treated rats. Moreover, renal morphology improved significantly in TVL and CAP treated animals.

CONCLUSION

TVL and CAP demonstrated marked improvement in renal function and morphology.