Profile of reactive oxygen species generation and antioxidative mechanisms in the maturing rat kidney

Antioxidant properties and cytotoxic effects of Oxalis corniculata on human Hepatocarcinoma (Hep-G2) cell line: an in vitro and in silico evaluation

Background

Oxalis corniculata is a well-known medicinal plant used in folk medicine for the management of many diseases. The aim is to determine the physico-chemical properties, microscopic study, phytochemical properties, in-silico, in-vitro antioxidant and anticancer activity on human Hepatocarcinoma (Hep-G2) cell line of O. corniculata plant extract.

Results

Microscopical study reaveals that presence of pericyclic fibres, starch gains, trichomes etc, and phytochemical screening is carried to find out secondary metabolites. The molecular docking study concluded that some of the phytocompounds showed inhibition of epidermal growth factor receptor tyrosine kinase domain (PDB ID: 1M17) inhibitor. Furthermore, ADMET and drug likeness study hints some of phytocompounds may act as lead for anticancer drug discovery and development. Among selected phytocompounds, compound apigenin possesses − 7.90 kcal/mol as compared to standard drug doxorubicin possesses − 7.63 kcal/mol against the epidermal growth factor receptor tyrosine kinase. The plant extract shown antioxidant activities based on the different tests were performed. The hydroalcoholic plant extracts were found to be selectively cytotoxic in vitro to human Hepatocarcinoma (Hep-G2) cell line with IC50values 34.494 ± 0.42 µg/ml and EAF showed at IC50 value 30.245 ± 0.58 µg/ml of the cells were inhibited at the concentration of 50 µg/ml as compared with standard doxorubicin at IC50 value 24.8939 ± 0.25 µg/ml, respectively.

Conclusion

The present study concluded that O. corniculata possesses potential antioxidant and cytotoxic properties based upon the computer aided drug design models and in-vitro activity.

Resveratrol ameliorates sepsis-induced acute kidney injury in a pediatric rat model via Nrf2 signaling pathway

Acute kidney injury (AKI) is a hyper-inflammation-induced abrupt loss of kidney function and has become a major public health problem. The cecal ligation and puncture (CLP) model of peritonitis in rat pups mimics the development of sepsis-induced pediatric AKI is pre-renal without morphological changes of the kidneys and high lethality. Resveratrol, a natural polyphenolic compound with low toxicity, has obvious anti-oxidant and anti-inflammatory properties. The present study aimed to determine whether resveratrol alleviates pediatric AKI and investigated the potential mechanism. Thus, a CLP model of 17-18 day-old rat pups was used to mimic the development of sepsis-induced AKI in children. In the group treated with resveratrol, renal injury induced by CLP was alleviated with downregulation of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and kidney injury molecule (KIM)-1 expression. Nuclear factor-erythroid-2-related factor 2 (Nrf2) signaling is known to effectively inhibit inflammation, the present study found that resveratrol reduced the lipopolysaccharide-induced inflammatory response in kidney cells in vitro and induced the activation of Nrf2 signaling, including accumulation of nuclear Nrf2 and increase of the expression of Nrf2 target genes heme oxygenase (HO)-1 and NAD(P)H dehydrogenase (quinone) 1 (NQO1); this was confirmed by the induction of the expression of HO-1 and NQO1 by treatment of resveratrol in vitro and in vivo. Of note, knockdown of Nrf2 effectively abrogated the downregulation of TNF-α, IL-1β and KIM-1 expression induced by resveratrol in vitro. These results suggested that resveratrol ameliorates sepsis-induced acute kidney injury in a pediatric model of AKI via the Nrf2 signaling pathway.

Age-dependent sensitivity of the mouse kidney to chronic nicotine exposure

BackgroundMany adolescents are exposed to nicotine via smoking, e-cigarette use, or second-hand smoke. Nicotine-induced renal oxidative stress and its long-term consequences may be higher in adolescents than in adults because of intrinsic factors in the adolescent kidney.MethodsAdolescent and adult male C57Bl/6J mice were subjected to 2 or 200 μg/ml nicotine, which closely emulates passive or active smoking, respectively, for 4 weeks. Extent of nicotine exposure (cotinine content), oxidative stress (HNE), renal function (creatinine), tubular injury (KIM-1), and pretreatment renal levels of select pro-oxidant (p66shc) and antioxidant (Nrf2/MnSOD) genes were determined. Impact of p66shc overexpression or Nrf2/MnSOD knockdown on low-/high-dose nicotine-induced oxidative stress was determined in cultured renal proximal tubule cells.ResultsDespite similar plasma/renal cotinine levels, renal HNE and KIM-1 contents were higher in adolescents compared with those in adults, whereas renal function was unaltered after passive or active smoking-equivalent nicotine exposure. Pretreatment levels of p66shc were higher, whereas Nrf2/MnSOD levels were lower in the adolescent kidney. In agreement with this, overexpression of p66shc or knockdown of Nrf2/MnSOD augmented nicotine-induced ROS production in renal proximal tubule cells.ConclusionChronic nicotine exposure incites higher oxidative stress in the adolescent than in adult kidney because of a pre-existent pro-oxidant milieu.

Effect of selenium pre-treatment on antioxidative enzymes and lipid peroxidation in Cd-exposed suckling rats

Since there are no data about the protective role of selenium (Se) against cadmium (Cd)-induced oxidative damage in early life, we studied the effect of Se supplementation on antioxidative enzyme activity and lipid peroxidation (through thiobarbituric acid reactive substances; TBARS) in suckling Wistar rats exposed to Cd. Treated animals received either Se alone for 9 days (8 μmol, i.e., 0.6 mg Se as Na(2)SeO(3) kg(-1) b.w., daily, orally; Se group), Cd alone for 5 days (8 μmol, i.e., 0.9 mg Cd as CdCl(2) kg(-1) b.w., daily, orally; Cd group), or pre-treatment with Se for 4 days and then co-treatment with Cd for the following 5 days (Se + Cd group). Our results showed that selenium supplementation, with and without Cd, increased SOD activity in the brain and kidney, but not in the liver and GSH-Px activity across all tissues compared to control rats receiving distilled water. Relative to the Cd group, Se + Cd group had higher kidney and brain SOD and GSH-Px activity (but not the liver), while in the liver caused increased and in the brain decreased TBARS level. These results suggest that Se stimulates antioxidative enzymes in immature kidney and brain of Cd-exposed rats and could protect against oxidative damage.

Hemodynamic changes in the kidney in a pediatric rat model of sepsis-induced acute kidney injury

Sepsis is a leading cause of acute kidney injury (AKI) and mortality in children. Understanding the development of pediatric sepsis and its effects on the kidney are critical in uncovering new therapies. The goal of this study was to characterize the development of sepsis-induced AKI in the clinically relevant cecal ligation and puncture (CLP) model of peritonitis in rat pups 17-18 days old. CLP produced severe sepsis demonstrated by time-dependent increase in serum cytokines, NO, markers of multiorgan injury, and renal microcirculatory hypoperfusion. Although blood pressure and heart rate remained unchanged after CLP, renal blood flow (RBF) was decreased 61% by 6 h. Renal microcirculatory analysis showed the number of continuously flowing cortical capillaries decreased significantly from 69 to 48% by 6 h with a 66% decrease in red blood cell velocity and a 57% decline in volumetric flow. The progression of renal microcirculatory hypoperfusion was associated with peritubular capillary leakage and reactive nitrogen species generation. Sham adults had higher mean arterial pressure (118 vs. 69 mmHg), RBF (4.2 vs. 1.1 ml·min(-1)·g(-1)), and peritubular capillary velocity (78% continuous flowing capillaries vs. 69%) compared with pups. CLP produced a greater decrease in renal microcirculation in pups, supporting the notion that adult models may not be the most appropriate for studying pediatric sepsis-induced AKI. Lower RBF and reduced peritubular capillary perfusion in the pup suggest the pediatric kidney may be more susceptible to AKI than would be predicted using adults models.

The Nrf2-Keap1 cellular defense pathway and heat shock protein 70 (Hsp70) response. Role in protection against oxidative stress in early neonatal unilateral ureteral obstruction (UUO)

Perturbation of renal tubular antioxidants and overproduction of reactive oxygen species may amplify the proinflammatory state of renal obstruction, culminating in oxidative stress and tubular loss. Here, we analyzed the heat shock protein 70 (Hsp70) response and the function and signal transduction of NF-E2-related protein 2 (Nrf2) transcription factor on oxidative stress modulation in obstruction. Rats were subjected to unilateral ureteral obstruction or sham operation and kidneys harvested at 5, 7, 10, and 14 days after obstruction. Hsp70 expression and Nrf2 activity and its downstream target gene products were assessed. After 10 and 14 days of obstruction, enhanced lipid peroxidation through higher thiobarbituric acid reactive substances levels and increased oxidative stress resulted in reduced total antioxidant activity and enhanced nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase activity were demonstrated. This was accompanied by decreased inducible Hsp70 expression and a progressive reduction of nuclear Nrf2 and its target gene products glutathione S-transferase A2 (GSTA2) and NADPH/quinone oxidoreductase 1 (NQO1), whereas the Nrf2 repressor Kelch-like ECH-associated protein-1 (Keap1) was upregulated. By contrast, on early obstruction for 7 days, lack of increased oxidative markers associated with higher inducible Hsp70 protein levels and a rapid nuclear accumulation of Nrf2, Keap1 downregulation, and mRNA induction of the identified Nrf2-dependent genes, NQO1 and GSTA2, were shown. For these results, we suggest that the magnitude of cytoprotection in early obstruction depends on the combined contribution of induced activation of Nrf2 upregulating its downstream gene products and Hsp70 response. Impaired ability to mount the biological response to the prevailing oxidative stress leading to renal injury was shown in prolonged obstruction.

Hsp70/nitric oxide relationship in apoptotic modulation during obstructive nephropathy

The functional integrity of the kidney depends on normal development as well as on physiological cell turnover. Apoptosis induction is essential for these mechanisms. Multiple mechanisms are unleashed during obstructive nephropathy, one of the most complex being programmed cell death that leads to renal tubular atrophy and tubular loss. This review will focus on the interaction of nitric oxide and Hsp70 and on the regulation of renal antiapoptotic and protective oxidative stress responses.

Protective effects of melatonin on renal failure in pinealectomized rats

AIM

The purpose of the current study was to investigate the effects melatonin on renal function.

METHODS

The histological appearance of the kidney and malondialdehyde, nitric oxide, glutathione and superoxide dismutase contents were determined. Serum creatinine and blood urea nitrogen levels were also assayed. Rats were divided as: Sham, pinealectomized (Px) and pinealectomized and treated with melatonin.

RESULTS

In Px group, malondialdehyde and nitric oxide levels were elevated when compared with the sham group. The Px group exhibited reduced superoxide dismutase activity and glutathione content. All of these harmful changes were restored by melatonin. Melatonin also ameliorated serum creatinine and blood urea nitrogen levels related to renal injury. The score for glomerular, tubular and interstitial changes was significantly higher in the Px group. Melatonin supplementation significantly reduced these parameters.

CONCLUSIONS

This protective effect may be associated with both melatonin's lipophilic and hydrophilic effects, thus providing on-site protection against free radical mediated damage.

Cytoprotective role of nitric oxide associated with Hsp70 expression in neonatal obstructive nephropathy

Nitric oxide (NO) has emerged as an important endogenous inhibitor of apoptosis. In this study, we postulated that the mechanism of apoptosis inhibition by NO would include stimulation of heat shock protein 70 (Hsp70) expression. Rats were subjected to unilateral ureteral obstruction (UUO) or sham operation, and kidneys were harvested 5 and 14 days after obstruction. After 14 days of obstruction, decreased endogenous NO and lower inducible nitric oxide synthase (iNOS) expression at mRNA and protein levels associated with downregulation of Hsp70 protein expression were shown in apoptosis induction, regulated by mitochondrial signal pathway, through the increased pro-apoptotic ratio Bax/BcL(2) and consequently caspase 3 activity. Conversely, 5 days after kidney obstruction, increased Hsp70 expression linked to increase NO and iNOS expression at transcriptional and post-transcriptional levels with absence of apoptotic response, were demonstrated. In obstructed neonatal rats, in vivo administration of l-Arginine induced heat shock protein 70 (Hsp70) expression, which was associated with cytoprotection from apoptosis and transiently decreased nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase activity. Opposite effects were obtained after nitro L-Arginine methyl ester (L-NAME) treatment. The interaction between B-cell lymphoma 2 anti-apoptotic members (BcL(2)) and Hsp70 in the presence of L-Arginine and L-NAME, was determined by coimmunoprecipitation. Binding of BcL(2) and Hsp70 increased after L-Arginine administration. These findings suggest that NO can produce resistance to obstruction-induced cell death by mitochondrial apoptotic pathway, through the induction of Hsp70 expression, in neonatal unilateral ureteral obstruction.

Protective role of aminoguanidine on gentamicin-induced acute renal failure in rats

The toxicity of aminoglycosides including gentamicin (GEN), the most widely used drug in this category, is believed to be related to the generation of reactive oxygen species (ROS) in the kidney. Aminoguanidine (AG) is known as an effective antioxidant and its free radical scavenger effects may protect GEN-induced acute renal failure (ARF). Therefore, this study was focused on investigating the possible protective effect of AG against GEN-induced nephrotoxicity in an in vivo rat model. We investigated the effects of AG on GEN-induced changes in renal tissue malondialdehyde (MDA) levels; nitric oxide (NO) generation; glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities; glutathione (GSH) content; serum creatinine (Cr) and blood urea nitrogen (BUN) levels. Morphological changes in the kidney were also examined using light microscopy. GEN administration to control group rats increased renal MDA and NO levels but decreased GSH-Px, SOD, CAT activities and GSH content. AG administration with GEN injection resulted in significantly decreased MDA, NO generation and increased GSH-Px, SOD, CAT activities and GSH content when compared with GEN alone. Serum levels of Cr and BUN significantly increased as a result of nephrotoxicity. Also, AG significantly decreased Cr and BUN levels. Morphological changes in the kidney, including tubular necrosis, intracellular edema, glomerular and basement membrane alterations were evaluated qualitatively. Both biochemical findings and histopathological evidence showed that administration of AG reduced the GEN-induced kidney damage. We propose that AG acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN both at the biochemical and histological level.

Ischemia-reperfusion leads to depletion of glutathione content and augmentation of malondialdehyde production in the rat heart from overproduction of oxidants: can caffeic acid phenethyl ester (CAPE) protect the heart?

During restoration of blood flow of the ischemic heart induced by coronary occlusion, free radicals cause lipid peroxidation with myocardial injury. Lipid peroxidation end-products, such as malondialdehyde (MDA), have been used to assess oxygen free radical-mediated injury of the ischemic-reperfused (I/R) myocardium in rats. This experimental study assessed the preventive effect of caffeic acid phenthyl ester (CAPE), antioxidant, on I/R-induced lipid peroxidation in the rat heart. We are also interested in the role of CAPE on glutathione (GSH) levels, an antioxidant whose levels are influenced by oxidative stress. I/R leads to the depletion of GSH which is the major intracellular nonprotein sulphydryl and plays an important role in the maintenance of cellular proteins and lipid in their functional state and acts primarily to protect these important structures against the threat of oxidation. In addition, we also examined morphologic changes in the heart by using light microscopy. The left coronary artery was occluded for 30 min and then reperfused for 120 min more before the experiment was terminated. CAPE (50 microM kg(-1)) was administered 10 min prior to ischemia and during occlusion by infusion. At the end of the reperfusion period, rats were sacrificed, and the heart was quickly removed for biochemical determination and histopathological analysis. I/R was accompanied by a significant increase in MDA production and decrease in GSH content in the rat heart. Administration of CAPE reduced MDA production and prevented depletion of GSH content. These beneficial changes in these biochemical parameters were also associated with parallel changes in histopathological appearance. These findings imply that I/R plays a causal role in heart injury due to overproduction of oxygen radicals or insufficient antioxidant and CAPE exert cardioprotective effects probably by the radical scavenging and antioxidant activities.

MYOCARDIAL ISCHEMIA/REPERFUSION-INDUCED OXIDATIVE RENAL DAMAGE IN RATS: PROTECTION BY CAFFEIC ACID PHENETHYL ESTER (CAPE)

Myocardial ischemia-reperfusion (MI/R) may induce renal damage. A rat model of M/IR injury was established. The left coronary artery was clamped for 30 min, constituting the ischemic period, and was then released for 120 min, thus constituting the reperfusion period. The purpose of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE), an antioxidant, on renal dysfunction in rats undergoing MI/R. CAPE (50 mumol/kg) was administered by infusion 10 min before ischemia and during occlusion. Hemodynamic changes were recorded during the different periods. At the end of the reperfusion period, rats were sacrificed, and the kidneys were quickly removed for biochemical determination and histopathological analysis. MI/R was accompanied by a significant increase in malondialdehyde (MDA) production and decrease in glutathione (GSH) content in the rat kidney. Administration of CAPE reduced MDA production and prevented depletion of GSH content. These beneficial changes in these biochemical parameters were also associated with parallel changes in histopathological appearance. These findings imply that MI/R plays a causal role in kidney injury through overproduction of oxygen radicals or insufficient antioxidant, and CAPE exerts renal-protective effects probably by its radical scavenging and antioxidant activities.

Protective role of caffeic acid phenethyl ester (cape) on gentamicin-induced acute renal toxicity in rats

The toxicity of gentamicin (GEN) in the kidney seems to relate to the generation of reactive oxygen species (ROS). Caffeic acid phenethyl ester (CAPE) has been demonstrated to have antioxidant, free radical scavenger and anti-inflammatory effects. It has been proposed that antioxidant maintain the concentration of reduced glutathione (GSH) may restore the cellular defense mechanisms and block lipid peroxidation thus protect against the toxicity of wide variety of nephrotoxic chemicals. We investigated the effects of CAPE on GEN-induced changes in renal malondialdehyde (MDA), a lipid peroxidation product, nitric oxide (NO) generation, superoxide dismutase (SOD), catalase (CAT) activities, GSH content, blood urea nitrogen (BUN) and serum creatinine (Cr) levels. Morphological changes in the kidney were also examined. A total of 32 rats were equally divided into four groups which were: (1) control, (2) injected with intraperitoneally (i.p.) GEN, (3) injected with i.p. GEN+CAPE and (4) injected with i.p. CAPE. GEN administration to control rats increased renal MDA and NO generation but decreased SOD and CAT activities, and GSH content. CAPE administration with GEN injections caused significantly decreased MDA, NO generation and increased SOD, CAT activities and GSH content when compared with GEN alone. Serum level of BUN and Cr significantly increased as a result of nephrotoxicity. CAPE also, significantly decreased serum BUN and Cr levels. Morphological changes in the kidney due to GEN, including tubular necrosis, were evaluated qualitatively. In addition, CAPE reduced the degree of kidney tissue damage induced by GEN. Both biochemical findings and histopathological evidence showed that administration of CAPE reduced the GEN-induced kidney damage. Our results indicated that CAPE acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN both at the biochemical and histological level. Thus, CAPE could be effectively combined with GEN treatment.

Renal apoptosis parallels ceramide content after prolonged ureteral obstruction in the neonatal rat

Obstructive nephropathy, the primary cause of renal insufficiency in infants, is characterized by progressive renal apoptosis. Ceramide is a sphingolipid known to stimulate apoptosis in the kidney. We investigated the effects of unilateral ureteral obstruction (UUO) on endogenous renal ceramide content and apoptosis in neonatal and adult rats. Animals were subjected to UUO or sham operation on the first day of life and were studied 3-28 days later. Adult rats were similarly treated and then studied 3 or 14 days later. In additional neonatal rats, the obstruction was removed after 5 days, with study at 14 or 28 days. Renal ceramide content was measured by diacylglycerol kinase assay, and apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick-end-labeling technique. Renal ceramide content was 50-fold higher in the 3-day neonatal compared with the adult kidney and 10-fold higher in the 7-day neonatal compared with the adult kidney, but there was no additional effect of UUO on ceramide content at these ages. However, after 14 or 28 days UUO in the neonate, renal ceramide was elevated compared with sham or intact opposite kidneys, and renal apoptosis was directly related to ceramide content (r = 0.99, P < 0.001). Moreover, renal ceramide was reduced by relief of obstruction (P < 0.05). There was less apoptosis in the obstructed kidney of the adult than the neonate, and UUO had no effect on ceramide content at 14 days in the adult. We conclude that prolonged UUO (at least 14 days duration) increases endogenous renal ceramide in the neonatal but not the adult rat. It is likely that this contributes to the prolonged renal apoptotic response of the neonatal obstructed kidney.