Protective effect of vitamin E and atorvastatin against potassium dichromate-induced nephrotoxicity in rats

Combined β-sitosterol and trimetazidine mitigate potassium dichromate-induced cardiotoxicity in rats through the interplay between NF-κB/AMPK/mTOR/TLR4 and HO-1/NADPH signaling pathways

Hexavalent chromium salt, like potassium dichromate (PD), is chromium's most precarious valence state in industrial wastes. Recently, there has been increasing interest in β-sitosterol (BSS), a bioactive phytosterol, as a dietary supplement. BSS is recommended in treating cardiovascular disorders due to its antioxidant effect. Trimetazidine (TMZ) was used traditionally for cardioprotection. Through the administration of BSS and TMZ, the cardiotoxic effects of PD were to be countered in this study, in addition to examining the precise mechanism of PD-induced cardiotoxicity. Thirty male albino rats were divided into five groups; the control group: administered normal saline daily (3 mL/kg); the PD group: administered normal saline daily (3 mL/kg); BSS group: administered BSS daily (20 mg/kg); TMZ group: administered TMZ daily (15 mg/kg); and the BSS + TMZ group: administered both BSS (20 mg/kg) and TMZ (15 mg/kg) daily. All experimental groups, except the control, received on the 19th day a single dose of PD (30 mg/kg/day, S.C.). Normal saline, BSS, and TMZ were received daily for 21 consecutive days p.o. The exposure to PD promoted different oxidative stresses, pro-inflammatory, and cardiotoxicity biomarkers. BSS or TMZ succeeded solely in reducing these deleterious effects; however, their combination notably returned measured biomarkers close to normal values. The histopathological investigations have supported the biochemical findings. The combination of BSS and TMZ protects against PD cardiotoxicity in rats by reducing oxidative stress and apoptotic and inflammatory biomarkers. It may be promising for alleviating and protecting against PD-induced cardiotoxicity in people at an early stage; however, these findings need further clinical studies to be confirmed. HIGHLIGHTS: • Potassium dichromate induces cardiotoxicity in rats through the upregulation of oxidative stress, proinflammatory, and apoptotic pathways biomarkers. • β-Sitosterol possesses a possible cardioprotective effect by modulating several signaling pathways. • Trimetazidine, the antianginal agent, has a potential cardioprotective impact on PD-intoxicated rat model. • The combination of β-Sitosterol and trimetazidine was the best in modulating different pathways involved in PD cardiotoxicity in rats via the interplay between NF-κB/AMPK/mTOR/TLR4 and HO-1/NADPH signaling pathways.

Atorvastatin prevents cadmium-induced renal toxicity in a rat model

In many industrial processes, worker exposure to cadmium causes kidney damage; thus, protection against cadmium toxicity is important in workplace health. Cadmium toxicity involves oxidative stress by increasing the levels of reactive oxygen species. Statins have shown antioxidant effects that might prevent this increase in oxidative stress. We investigated the potential effects of atorvastatin pretreatment in protecting experimental rats against kidney toxicity caused by cadmium. Experiments were performed on 56 adult male Wistar rats (200 ± 20 g), randomly assigned to eight groups. Atorvastatin was administered by oral gavage for 15 days at 20 mg/kg/day, starting 7 days before cadmium chloride intra-peritoneal administration (at 1, 2, and 3 mg/kg) for 8 days. On day 16, blood samples were collected, and kidneys were excised to evaluate the biochemical and histopathological changes. Cadmium chloride significantly increased malondialdehyde, serum creatinine, blood urea nitrogen, and decreased superoxide dismutase, glutathione, and glutathione peroxidase levels. Pre-administration of rats with atorvastatin at a dose of 20 mg/kg decreased blood urea nitrogen, creatinine, and lipid peroxidation, increased the activities of antioxidant enzymes, and prevented changes in physiological variables compared with animals that were not pretreated. Atorvastatin pretreatment prevented kidney damage following exposure to toxic doses of cadmium. In conclusion, atorvastatin pretreatment in rats with cadmium chloride-induced kidney toxicity could reduce oxidative stress by changing biochemical functions and thereby decreasing damage to kidney tissue.

Insight into the hepatoprotective, hypolipidemic, and antidiabetic impacts of aliskiren in streptozotocin-induced diabetic liver disease in mice

BACKGROUND

Diabetic hepatopathy is a serious complication of poorly controlled diabetes mellitus. An efficient antidiabetic drug which keeps normal liver tissues is not available. The renin-angiotensin system has been reported to be involved in both diabetic state and liver function. Aliskiren is a direct renin inhibitor and a recently antihypertensive drug with poly-pharmacological properties. The aim of the current study is to explore the possible hepatoprotective effects and mechanisms of action of aliskiren against streptozotocin (STZ) induced liver toxicity.

METHODS

Mice were distributed to 3 groups; first: the normal control group, second: the diabetic control group, third: the diabetic group which received aliskiren (25 mg/kg; oral) for 4 weeks. At the end of the treatment period, plasma glucose, insulin, lipid profile, oxidative stress, and liver function tests were evaluated spectrophotometrically. ELISA technique was used to measure the expression levels of TNF-α and adiponectin. Furthermore, a Histopathological examination of liver samples was done.

RESULTS

It was shown that aliskiren treatment ameliorated the STZ-induced oxidative stress and elevated inflammatory biomarkers, hypercholesterolemia, serum aminotransferases and alkaline phosphatase levels in diabetic mice. In addition, hepatocellular necrosis, and fibrosis were improved by aliskiren treatment.

CONCLUSION

aliskiren protects against the liver damage caused by STZ-induced diabetes. This can be explained by its ability to block angiotensin-II, and its anti-diabetic, hypocholesterolemic, antioxidant and anti-inflammatory effects. Aliskiren could be a novel therapeutic strategy to prevent liver diseases associated with hypertension and diabetes mellitus.

Nephroprotective role of Echinacea purpurea against potassium dichromate-induced oxidative stress, inflammation, and apoptosis in rats

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium [Cr(VI)], is widely recognized as a potential nephrotoxic in humans and animals. Its toxicity is associated with the overproduction of free radicals, which induces oxidative damage. Echinacea purpurea (L.) Moench is an herbaceous perennial plant rich in phenolic components and frequently used for its medicinal benefits. The current work evaluated the effectiveness of E. purpurea (EP) against oxidative stress and nephrotoxicity induced by potassium dichromate in male rats. Male Wistar rats were divided into four groups: control, E. purpurea (EP; 50 mg/kg; once daily for 3 weeks), hexavalent chromium (Cr(VI); 15 mg/kg; single intraperitoneal dose), and EP + Cr(VI) where rats were pretreated with EP for 3 weeks before receiving CrVI, respectively. Results revealed that rats exposed to Cr(VI) showed a significant increase in PC, TBARS, and H₂ O₂ , kidney function biomarkers (Urea, creatinine, and uric acid), lactate dehydrogenase activity (LDH), TNF-α, IL-18, nuclear factor kappa B (NFκB), and IGF-1 (Insulin-like growth factor-1) levels as well as a considerable decline in metallothionein (MT), glutathione (GSH) content, enzymatic antioxidants (SOD, CAT, GPx, GR, and GST), alkaline phosphatase (ALP) activities, and protein content. Cr(VI) induced apoptosis in kidney tissues as revealed by upregulation of Bax and caspase 3 and downregulation of Bcl-2. Furthermore, EP treatment ameliorated the Cr(VI)-induced histopathological and ultrastructure variations of kidney tissue, which was confirmed by the biochemical and molecular data. It is clear from the results of this study that EP exerts nephroprotective effects by improving the redox state, suppressing inflammatory reaction and cell apoptosis as well as ameliorating the performance of kidney tissue architecture, which is eventually reflected by the improvement of kidney function in rats.

Myometrial Calcium and Potassium Channels Play a Pivotal Role in Chromium-Induced Relaxation in Rat Uterus: an In Vitro Study

Hexavalent chromium, a well-known environmental toxicant, adversely affects female reproduction and results in abnormal implantation, fetal resorption, and reduction in litter size. Uterine myogenic activity is under control of number of receptors and ion channels, and it regulates fetal-implantation and feto-maternal communication. Despite several known adverse effects of chromium on female reproduction, direct action of chromium on myometrial activity is yet to be understood. In the present study, the effect of in vitro exposure of hexavalent chromium (Cr-VI) on the myogenic activity of isolated myometrial strips of rats was evaluated after mounting the tissue in thermostatically (37 ± 0.5 °C) controlled organ bath under a resting tension of 1 g. Chromium produced concentration-dependent (0.1 nM-0.1 mM) inhibitory effect on myometrial activity. Following pre-treatment of the myometrial strips with glibenclamide (a K_ATP channel blocker) and 4-aminopyridine (a K_v channel blocker), the concentration-response curve (CRC) of chromium was significantly (P < 0.05) shifted towards right with decrease in the maximum relaxant effect. Contractile effects of CaCl₂ and BAY K-8644 (a selective opener of L-type Ca²⁺ channel) were significantly (P < 0.05) attenuated in the presence of chromium. Chromium-induced myometrial relaxation was also significantly (P < 0.05) reduced in the presence of ICI 118,551 (a selective β₂-antagonist) and SR 59230A (a selective β₃-antagonist). These findings evidently suggest that chromium produced relaxant effect on rat myometrium by interfering with Ca²⁺ entry through voltage-dependent Ca²⁺ channels, and by interacting with beta-adrenoceptors (β₂ and β₃) and potassium channels (especially K_ATP and K_v channels). Graphical Abstract Proposed signaling pathway(s) of chromium (VI)-induced myometrial relaxations in rats. K_ATP: ATP-sensitive K⁺ channel; K_V: voltage-dependent K⁺ channel; VDCC: voltage-dependent Ca²⁺ channel; [Ca²⁺]_i: intracellular calcium concentration, stimulatory mechanism, inhibitory mechanism.

Has vitamin E any shreds of evidence in cisplatin-induced toxicity

Cisplatin is one of the highly consumed and effective antitumor agents whose clinical application is accompanied by nephrotoxicity adverse reaction. Also, other complications such as ototoxicity and hepatotoxicity are a matter of concern. Today, it is suggested that cisplatin-associated toxicities are mainly induced by free radicals production, which will result in oxidative organ injury. The evidence is growing over the protective effects of antioxidants on cisplatin-induced adverse reactions especially nephrotoxicity. The possible protective effects of vitamin E and its derivative in cisplatin-induced nephrotoxicity and ototoxicity are reviewed here at the light of pertinent results from basic and clinical research. Administration of vitamin E alone or in combination with other antioxidant agents could cause amelioration in oxidative stress biomarkers such as decreasing the level of malondialdehyde, reducing serum urea and creatinine, and also enhancing the activities of renal antioxidant enzymes including renal catalase, glutathione-S-transferase, and superoxide dismutase. Although the data from most of the studies are in favors of protective effects of vitamin E against cisplatin-induced toxicity, more clinical trials are needed to clarify the clinical importance of vitamin E administration as an antioxidant during cisplatin therapy in cancer condition.

The ameliorative effects of ceftriaxone and vitamin E against cisplatin-induced nephrotoxicity

Nephrotoxicity is a common adverse effect of treatment with cisplatin (CDDP). This study was performed to evaluate the antioxidant and nephroprotective efficacy of ceftriaxone (CTX) and vitamin E (Vit.E), alone and in combination against CDDP-induced acute renal injury. Fifty-six male albino rats were equally divided into seven groups, receiving (I) normal saline, (II) CTX (100 mg/kg, intraperitoneal [i.p] injection), (III) Vit.E (100 mg/kg orally), (IV) CDDP (5 mg/kg i.p injection), (V) CDDP plus CTX, (VI) CDDP plus Vit.E, and (VII) CDDP plus CTX in combination with Vit.E. All treatments were administered daily for 10 days except CDDP, which was given as a single dose at the sixth day of the study. Compared to normal control rats, CDDP-injected rats showed significantly (p < 0.05) higher serum levels of renal injury biomarkers (uric acid, urea, and creatinine) and tumor necrosis factor-α (TNF-α), as well as increased renal tissue concentrations of malondialdehyde, nitric oxide, and TNF-α. Moreover, CDDP administration was associated with significantly lower (p < 0.05) renal tissue levels of reduced glutathione and activities of endogenous antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase) and total antioxidant capacity. All these alterations were significantly ameliorated in CDDP-injected rats, receiving CTX and/or Vit.E, compared to rats receiving CDDP alone. Interestingly, the antioxidant and anti-inflammatory effects were more marked in the CTX-Vit.E combination group, compared to groups receiving either drug alone. In conclusion, CTX and Vit.E (especially in combination) could counteract the nephrotoxic effect of CDDP, probably through their antioxidant activities.

Oxidative Effects of Potassium Dichromate on Biochemical, Hematological Characteristics, and Hormonal Levels in Rabbit Doe (Oryctolagus cuniculus)

The present study was conducted to evaluate the toxicity induced by the increasing doses of potassium dichromate in rabbit doe. Twenty-eight adult does of 6 months of age were divided into four groups (A, B, C, and D; n = 7), with comparable average body weight (bw). Group A rabbits received only distilled water daily and served as a control, while groups B, C, and D received, respectively, 10 mg/kg bw, 20 mg/ kg bw, and 40 mg/kg bw of potassium dichromate via gavage for 28 days, after which animals were anesthetized with ether vapor and sacrificed. Blood samples were obtained via cardiac puncture and collected without anticoagulant for biochemical dosages and with anticoagulant (EDTA) for complete blood count. Follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were dosed in serum and in homogenates of ovary with the help of AccuDiagTM ELISA kits from OMEGA DIAGNOSTICS LTD (Scotland, England) while respecting the immuno-enzymatic method. Activities of superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and concentration of malondialdehyde (MDA) in liver, kidney, ovary and uterus were measured. Hematology revealed a significant (p < 0.05) decrease in mean values of hemoglobin and platelets while white blood cells and lymphocytes showed a significant (p < 0.05) increase in exposed groups. No significant (p > 0.05) difference was registered in monocytes, red blood cells, hematocrits, and plaquetocrits values with respect to the control. No matter the organ considered, no significant (p > 0.05) change was recorded in weight and volume. Nephrotoxicity analysis registered a significant (p < 0.05) increase in urea and creatinine, unlike renal tissue protein, which decreased significantly (p < 0.05). However, hepatotoxicity registered no significant (p > 0.05) variation in aspartate aminotransferase but total protein, alanine aminotransferase, and total cholesterol increased significantly (p < 0.05), while hepatic tissue protein revealed a significant (p < 0.05) decrease. Analysis on reproductive parameters showed a significant (p < 0.05) decrease in ovarian and uterine tissue proteins, as well as in follicle stimulating hormone, luteinizing hormone, and estradiol. Oxidative stress markers recorded no significant (p > 0.05) difference in glutathione reductase except in ovary where a significant (p < 0.05) decrease was seen when compared with the control, while catalase revealed a significant (p < 0.05) decrease, except in liver where there was no significant (p > 0.05) change. Superoxide dismutase and malondialdehyde recorded a significant (p < 0.05) decrease and increase respectively, with respect to the control. Results obtained from this study showed that the reduction process of chromium in tissues may cause the generation of reactive oxygen species, which are involved in hematoxic, nephrotoxic, hepatotoxic, and reproductive toxicity effects.

Effects of phoxim-induced hepatotoxicity on SD rats and the protection of vitamin E

Currently, public pay more attention to the adverse effect of organophosphate pesticides on human and animal health and on the environment in developing nations. Vitamin E may protect the hepatocyte and increase the function of liver. The study was to investigate the effects of phoxim-induced hepatotoxicity on Sprague Dawley (SD) rats and the protection of vitamin E. SD rats received by gavage 180 mg kg^-1 (per body weight) of phoxim, 200 mg kg^-1 (per body weight) of vitamin E, and phoxim + vitamin E. The results showed that exposure to phoxim elevated liver coefficient; glutamyl transpeptidase (GGT), aspartate aminotransferase, alkaline phosphatase, total bilirubin, total bile acid, and alanine aminotransferase in the serum; ROS in the liver; and the expression of p53, Bax, CYP2E1, ROS, caspase-9, caspase-8, and caspase-3, while phoxim caused a reduction of total protein, albumin, and cholinesterase in the serum; acetylcholinesterase, total antioxidant capacity, glutathione peroxidase, and glutathione in the liver; and the expression of Bcl-2. Vitamin E modified the phoxim-induced hepatotoxicity by reducing the GGT in the serum, malondialdehyde in the liver, and the expression of CYP2E1 significantly. There were no significant changes of globulin in the serum, the activity of catalase in the liver, as well as expression levels of Fas and Bad in the liver. Overall, subacute exposure to phoxim induced hepatic injury, oxidative stress damage, and cell apoptosis. Vitamin E modified phoxim-induced hepatotoxicity slightly. And, vitamin E minimized oxidative stress damage and ultrastructural changes in rat hepatocytes notably.

Reactive oxygen species mediate Terbufos-induced apoptosis in mouse testicular cell lines via the modulation of cell cycle and pro-apoptotic proteins

Terbufos (S-t-butylthiomethyl-O,O-diethyl phosphorodithioate) is a highly toxic organophosphate which is extensively used as an insecticide and nematicide. Chronic exposure to terbufos causes neuronal injury and predisposes to neurodegenerative diseases. Accumulating evidence has shown that the exposure to terbufos, as an occupational risk factor, may also cause reproductive disorders. However, the exact mechanisms of reproductive toxicity remain unclear. The present study aimed to investigate the toxic effect of terbufos on testicular cells and to explore the mechanism of toxicity on a cellular level. The cytotoxic effects of terbufos on mouse immortalized spermatogonia (GC-1), spermatocytes (GC-2), Leydig (TM3), and Sertoli (TM4) cell lines were assessed by MTT assays, caspase activation, flow cytometry, TUNEL assay, Western blot, and cell cycle analysis. The exposure to different concentrations of terbufos ranging from 50 to 800 μM for 6 h caused significant death in all the used testicular cell lines. Terbufos increased reactive oxygen species (ROS) production, reduced mitochondrial membrane potential, and initiated apoptosis, which was confirmed by a dose-dependent increase in the number of TUNEL-positive apoptotic cells. Blocking ROS production by N-acetyl cysteine (NAC) protected GC-1 cells from terbufos-induced cell death. The results demonstrated that terbufos induces ROS, apoptosis, and DNA damage in testicular cell lines and it should be considered potentially hazardous to testis. Together, this study provided potential molecular mechanisms of terbufos-induced toxicity in testicular cells and suggests a possible protective measure. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1888-1898, 2016.

Anti-diabetic and renoprotective effects of aliskiren in streptozotocin-induced diabetic nephropathy in female rats

Since chronic kidney disease due to diabetic nephropathy (DN) is becoming an ever larger health burden worldwide, more effective therapies are desperately needed. In the present study, the anti-diabetic and renoprotective effects of aliskiren have been evaluated in streptozotocin (STZ)-induced DN in rats. DN was induced by a single intraperitoneal injection of STZ (65 mg/kg). Three weeks after STZ, rats were divided into four groups; normal, diabetic, diabetic treated with gliclazide (10 mg/kg/day) for 1 month, and diabetic treated with aliskiren (50 mg/kg/day) for 1 month. At the end of the experiment, mean arterial blood pressure and heart rate were recorded. Rats were then euthanized and serum was separated for determination of glucose, insulin, kidney function tests, superoxide dismutase activity (SOD), adiponectin, and tumor necrosis factor-alpha (TNF-α). One kidney was used for estimation of malondialdehyde (MDA), reduced glutathione (GSH), and nitric oxide (NO) contents. Other kidney was used for histopathological study and immunohistochemical measurement of caspase-3 and transforming growth factor beta (TGF-β). In addition, islets of Langerhans were isolated from normal rats by collagenase digestion technique for in vitro study. Aliskiren normalized STZ-induced hyperglycemia, increased insulin level both in vivo and in vitro, normalized kidney function tests and blood pressure, and alleviated STZ-induced kidney histopathological changes. This could be related to the ability of aliskiren toward preserving hemodynamic changes and alleviating oxidative stress and inflammatory and apoptotic markers induced by STZ in rats. However, aliskiren was more effective than gliclazide in relieving STZ-induced DN. These findings support the beneficial effect of aliskiren treatment in DN which could be attributed to its anti-diabetic, renoprotective, antioxidant, anti-inflammatory, and anti-apoptotic effects. Moreover, clinical studies are required to establish the effectiveness of aliskiren treatment in patients suffering from hypertension and diabetes.