Ameliorative effects of pentoxifylline on NOS induced by diabetes in rat kidney

Long-Term Exposure of Cultured Astrocytes to High Glucose Impact on Their LPS-Induced Activation

Diabetes mellitus is associated with various complications, mainly caused by the chronic exposure of the cells to high glucose (HG) concentrations. The effects of long-term HG exposure in vitro accompanied by lipopolysaccharide (LPS) application on astrocytes are relatively unknown. We used cell medium with normal (NG, 5.5 mM) or high glucose (HG, 25 mM) for rat astrocyte cultures and measured the release of NO, IL-6, β-hexosaminidase and cell survival in response to LPS. We first demonstrated that HG long-term incubation of astrocytes increased the release of β-hexosaminidase without decreasing MTT-detected cell survival, suggesting that there is no cell membrane damage or astrocyte death but could be lysosome exocytosis. Different from what was observed for NG, all LPS concentrations tested at HG resulted in an increase in IL-6, and this was detected for both 6 h and 48 h treatments. Interestingly, β-hexosaminidase level increased after 48 h of LPS and only at HG. The NO release from astrocytes also increased with LPS application at HG but was less significant. These data endorsed the original hypothesis that long-term hyperglycemia increases proinflammatory activation of astrocytes, and β-hexosaminidase could be a specific marker of excessive activation of astrocytes associated with exocytosis.

A natural products solution to diabetic nephropathy therapy

Diabetic nephropathy is one of the most common complications in diabetes. It has been shown to be the leading cause of end-stage renal disease. However, due to their complex pathological mechanisms, effective therapeutic drugs other than angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which have been used for 20 years, have not been developed so far. Recent studies have shown that diabetic nephropathy is characterized by multiple signalling pathways and multiple targets, including inflammation, apoptosis, pyroptosis, autophagy, oxidative stress, endoplasmic reticulum stress and their interactions. It definitely exacerbates the difficulty of therapy, but at the same time it also brings out the chance for natural products treatment. In the most recent two decades, a large number of natural products have displayed their potential in preclinical studies and a few compounds are under invetigation in clinical trials. Hence, many compounds targeting these singals have been emerged as a comprehensive blueprint for treating strategy of diabetic nephropathy. This review focuses on the cellular and molecular mechanisms of natural prouducts that alleviate this condition, including preclinical studies and clinical trials, which will provide new insights into the treatment of diabetic nephropathy and suggest novel ideas for new drug development.

Effects of Simo decoction on gastric motility of diabetic rats

BACKGROUND

To investigate the effects of simo decoction (SMD) on the gastric motility of diabetic rats.

METHODS

Diabetic rats were gavaged with various doses of SMD (0.15, 1.5, and 3.0 ml/kg/d) or saline, and their blood glucose levels and body weight were monitored. Gastric emptying and antral motility were assessed by phenol red retention and contractions of antral strips, respectively. The levels of substance P (SP), vasoactive intestinal peptide (VIP), and neurogenic nitric oxide synthase (nNOS) in the gastric antrum were determined by real-time polymerase chain reaction and Western blot.

RESULTS

Gastric emptying was delayed in diabetic rats (p < 0.01 vs. non-diabetic controls) but accelerated after SMD administration (p < 0.01). The contractions of antral strips were reduced in diabetic rats (p < 0.01 vs. non-diabetic controls) but improved after SMD intervention (p < 0.05). The mRNA expressions of SP, VIP, and nNOS in diabetic rats were downregulated compared with non-diabetic controls (all p < 0.01). Simo decoction treatment did not affect the expression of these factors in diabetic rats. The protein levels of SP, VIP, and nNOS in diabetic rats were decreased (p < 0.01), increased (p < 0.01), and comparable (p > 0.05), respectively, in comparison with non-diabetic controls. Simo decoction administration increased SP protein expression (p < 0.01) and decreased the levels of VIP (p < 0.01) and nNOS (p < 0.01) in diabetic rats.

CONCLUSIONS

Simo decoction improved gastric dysmotility of diabetic rats possibly by upregulating SP and downregulating VIP and nNOS.

Pentoxifylline and berberine mitigate diclofenac-induced acute nephrotoxicity in male rats via modulation of inflammation and oxidative stress

Nephrotoxicity (NT) is a renal-specific situation caused by different toxins and drugs like non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs like diclofenac (DCF) lead to glomerular dysfunction. Pentoxifylline (PTX) and berberine (BER) have antioxidant and anti-inflammatory properties. Thus, the objective of the present study was to investigate the ameliorative effect of PTX, BER and their combination against DCF-mediated acute NT. Induction of acute NT was done via DCF injection (150 mg/kg I.P, for 6 days) in rats. PTX 200 mg/kg, BER 200 mg/kg and their combination were administrated for 6 days prior to DCF injection and concurrently with DCF for additional 6 days. Acute NT was evaluated biochemically and histopathologically by measuring blood urea (BU), serum creatinine (SCr), kidney injury molecule-1(KIM-1), integrin (ITG), and vitronectin (VTN), interleukin (IL)-18, Neutrophil gelatinase-associated lipocalin (NGAL), glomerular filtration rate (GFR), superoxide dismutase (SOD) and glutathione (GSH) and malondialdehyde (MDA) with the scoring of histopathological alterations. PTX, BER and their combination significantly (P < 0.05) attenuated biochemical and histopathological changes in DCF-mediated acute NT by amelioration of BU, SCr, KIM-1, ITG, VTN, IL-18, NGAL, GFR, SOD, GSH, MDA and scoring of histopathological alterations. The combined effects of PTX and BER produced more significant effects (P < 0.05) than either PTX or BER when used alone against DCF-induced acute NT. In conclusion, BER and BTX were found to have potential renoprotective effects against DCF-induced NT in rats by inhibiting inflammatory reactions and oxidative stress.

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

AphaMax®, an Aphanizomenon Flos-Aquae Aqueous Extract, Exerts Intestinal Protective Effects in Experimental Colitis in Rats

BACKGROUND

Aphanizomenon flos-aquae (AFA) is a unicellular cyanobacterium considered to be a "superfood" for its complete nutritional profile and beneficial properties. We investigated possible beneficial effects of an AFA extract, commercialized as AphaMax^®, containing concentrated amount of phycocyanins and phytochrome, in 2,4 dinitrobenzensulfonic acid(DNBS)-induced colitis in rats.

METHODS

Effects of preventive oral treatment of AphaMax^® (20, 50 or 100 mg/kg/day) in colitic rats were assessed and then macroscopic and microscopic analyses were performed to evaluate the inflammation degree. Myeloperoxidase (MPO) activity and NF-κB, pro-inflammatory citockines, cycloxygenase-2 (COX-2), and inducible NOS (iNOS) levels of expression were determined, as Reactive Oxygen Species (ROS) and nitrite levels.

RESULTS

AphaMax^® treatment attenuated the severity of colitis ameliorating clinical signs. AphaMax^® reduced the histological colonic damage and decreased MPO activity, NF-κB activation, as well as iNOS and COX-2 expression. AphaMax^® treatment improved the altered immune response associated with colonic inflammation reducing IL-1β, IL-6 expression. Lastly, AphaMax^® reduced oxidative stress, decreasing ROS and nitrite levels.

CONCLUSIONS

Preventive treatment with AphaMax^® attenuates the severity of the inflammation in DNBS colitis rats involving decrease of the NF-kB activation, reduction of iNOS and COX-2 expression, and inhibition of oxidative stress. Due its anti-inflammatory and antioxidant proprieties AphaMax^® could be a good candidate as a complementary drug in inflammatory bowel disease (IBD) treatment.

Piperazine ferulate ameliorates the development of diabetic nephropathy by regulating endothelial nitric oxide synthase

Diabetic nephropathy (DN) is among the most common complications of diabetes mellitus. The disorder is associated with a decrease in the activity of the nitric oxide synthase/nitric oxide system. Piperazine ferulate (PF) is widely used for the treatment of kidney disease in China. The aim of the present study was to examine the effects of PF on streptozotocin (STZ)‑induced DN and the underlying mechanism of this process. STZ‑induced diabetic mice were intragastrically administered PF (100, 200 and 400 mg/kg/body weight/day) for 12 weeks. At the end of the treatment period, the parameters of 24‑h albuminuria and blood urea nitrogen, creatinine and oxidative stress levels were measured. Hematoxylin and eosin staining, periodic acid‑Schiff staining and electron microscopy were used to evaluate the histopathological alterations. mRNA and protein expression of endothelial nitric oxide synthase (eNOS) were measured by quantitative polymerase chain reaction and western blotting, respectively. PF significantly decreased blood urea nitrogen and creatinine levels and 24‑h albuminuria, and it alleviated oxidative stress, improved glomerular basement membrane thickness and caused an upregulation in eNOS expression and activity levels in diabetic mice. In addition, high glucose decreased eNOS expression levels, whereas PF caused a reversal in the nitric oxide (NO) levels of glomerular endothelial cells. The present results suggested that PF exhibited renoprotective effects on DN. The mechanism of its action was associated with the regulation of eNOS expression and activity.

Synergistic effect of berberine and pentoxifylline in attenuation of acute kidney injury

Objective

To evaluate the renoprotective effects of berberine and/or pentoxifylline in reduction of diclofenac-induced acute kidney injury (AKI) in rats.

Material and Methods

Fifty male Sprague-Dawley rats were allocated into five groups, Group 1: Rats treated with distilled water plus normal saline for 12 days. Group 2: Rats treated with distilled water plus diclofenac for 12 days. Group 3: Rats treated with berberine plus diclofenac for 12 days. Group 4: Rats treated with pentoxifylline plus diclofenac for 12 days. Group 5: Rats treated with berberine + pentoxifylline plus diclofenac 15 mg/kg for 12 days. Blood urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecules (KIM-1), and cystatin-c were used to measure the severity of AKI.

Results

Diclofenac led to significant AKI by significant elevation of blood urea, serum creatinine, KIM-1, and NGAL. Treatment with berberine showed no significant effect on all biomarkers level compared to diclofenac group except on serum KIM-1 level which also seen in the pentoxifylline group whereas combination of berberine and pentoxifylline led to more significant effect in the reduction of all renal biomarkers.

Conclusion

Combination of berberine with pentoxifylline illustrated a synergistic effect in attenuation of diclofenac-induced AKI.

Are the Therapeutic Effects of Huangqi (Astragalus membranaceus) on Diabetic Nephropathy Correlated with Its Regulation of Macrophage iNOS Activity?

Objective

To investigate the correlation between the clinical effects of Huangqi (Astragalus membranaceus) on different stages of diabetic nephropathy (DN) and the pharmacological effect of Huangqi on the activity of inducible nitric oxide synthase (iNOS) in macrophages in different states.

Methods

The PubMed, China National Knowledge Infrastructure, and Wanfang databases were searched. Clinical data was sourced from papers on treatment of different stages of DN with Huangqi, and pharmacological data was from papers on the effects of Huangqi on the iNOS activity of macrophages in a resting or an activated state.

Results

Meta-analysis of Huangqi injections on stages III and III-IV DN and randomized controlled trials on other stages showed that Huangqi had therapeutic effects on different stages of DN and on macrophages in different states: inducing normal macrophages in a resting state to generate nitric oxide (NO), tumor necrosis factor-α, and so forth upon iNOS activation; inhibiting NO generation by normal lipopolysaccharide- (LPS-) activated macrophages; and enhancing NO generation by LPS-induced macrophages from patients with renal failure.

Conclusions

Huangqi can regulate iNOS activity of macrophages in different states in vitro. These biphasic or antagonistic effects may explain why Huangqi can be used to treat different stages of DN.

An update on diabetic kidney disease, oxidative stress and antioxidant agents

Diabetes mellitus is a metabolic disease that is defined by relative or absolute deficiency of insulin secretion. Diabetic kidney disease seems to be one of the most frequent complications of diabetes mellitus. Based on evidence, increased free-radical formation and/or diminished antioxidant defenses induce oxidative stress that is implicated in the pathogenesis of diabetic kidney disease. It is evident that diabetic state induces oxidative stress through different signaling pathways as well as reactive oxygen species (ROS) formation that attributes to the activation of various downstream signaling cascade leading to structural the way to structural and functional changes in kidney.

The effects of tadalafil and pentoxifylline on apoptosis and nitric oxide synthase in liver ischemia/reperfusion injury

The aim of this study was to investigate the effects of tadalafil (TDF) and pentoxifylline (PTX) on hepatic apoptosis and the expressions of endothelial and inducible nitric oxide synthases (eNOS and iNOS) after liver ischemia/reperfusion (IR). Forty Wistar albino rats were randomly divided into five groups (n=8) as follows: sham group; IR group with ischemia/reperfusion alone; low-dose and high-dose TDF groups received 2.5 mg/kg and 10 mg/kg TDF, respectively; and PTX group received 40 mg/kg PTX. Blood was collected for the analysis of serum alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, uric acid, malondialdehyde (MDA), and total antioxidant capacity (TAC). MDA and TAC also were measured in liver tissue. Histopathological examination was performed to assess the severity of hepatic injury. Apoptosis was evaluated using the apoptosis protease-activating factor 1 (APAF-1) antibody; the expressions of eNOS and iNOS were also assessed by immunohistochemistry in all groups. Serum alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, uric acid, MDA, and TAC, tissue MDA and TAC levels, hepatic injury, and score for extent and for intensity of eNOS, iNOS, and apoptosis protease-activating factor 1 were significantly different in TDF and PTX groups compared to the IR group. High dose-TDF and PTX have the best protective effect on IR-induced liver tissue damage. This study showed that TDF and PTX supplementation may be helpful in preventing free oxygen radical damage, lipid peroxidation, hepatocyte necrosis, and apoptosis in liver IR injury and minimizing liver damage.