Simvastatin attenuates chromium-induced nephrotoxicity in rats

Effects of Aronia melanocarpa and Hypericum perforatum aqueous extracts on hexavalent chromium induced toxicity in rat's thyrocytes

BACKGROUND

Hexavalent chromium known as oxidizing agent is able to form reactive oxygen species. Aronia melanocarpa and Hypericum perforatum are two plants known for their antioxidant effects. Our study aimed to establish if CrVI induces apoptosis and structural changes in thyrocytes and if its effect can be counteracted by the administration of both extracts.

MATERIALS AND METHODS

Wistar rats divided in five groups: C - distilled water (DW), Cr - 75 mg/L CrVI in DW for 3 months, Cr 2 - 75 mg/L CrVI in DW for 3 months followed by 1 month DW, CrA - 3 months 75 mg/L CrVI in DW and 1 month Aronia 2.5% extract, CrH - 3 months 75 mg/L CrVI in DW and 1 month Hypericum 2.5% extract. Histological assessment and qRT-PCR for evaluation of BAX and Bcl2 protein levels performed on thyroid samples.

RESULTS

The Cr and Cr2 groups were those with altered cytoarchitecture: increase in the diameter of many thyroid follicles, a decrease in their number, a decrease in the height of the follicular cells. The histological examination of the CrH group revealed almost recovery of structural architecture. The BAX gene levels were higher in the Cr and Cr2 groups indicating the apoptotic activity of chromium. In extract receiving groups the BAX gene expressions were significantly lower, but the lowest level presented the CrH group. Bcl2 gene expression levels indicate antiapoptotic activity being elevated in the Cr group, followed by CrA, Cr2, and CrH groups. The BAX/Bcl2 ratio which significantly increased in the case of the Cr and Cr2 group compared to the groups that were administered the two plant extracts.

CONCLUSION

The results obtained in this study confirm that CrVI has toxic effects on thyroid endocrine cells and H. perforatum has stronger antioxidant properties against the action of hexavalent chromium in thyrocytes than A. melanocarpa.

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.

Nephroprotective Efficacy of Selenium and Zinc Against Potassium Dichromate-Induced Renal Toxicity in Pregnant Wistar Albino Rats

Hexavalent chromium (CrVI) compounds are potent toxicants commonly used in numerous industries. Thus, potential toxic effects and health hazards are of high relevance. Selenium (Se) and zinc (Zn) are known for their antioxidant and chemoprotective properties. However, little is known about their protective effects against CrVI-induced renal damage during pregnancy. In this context, the present study aimed to investigate the protective efficacy of these two essential elements against potassium dichromate-induced nephrotoxicity in pregnant Wistar Albino rats. Female rats were divided into control and four treated groups of six each receiving subcutaneously on the 3rd day of pregnancy, K₂Cr₂O₇ (10 mg/kg, s.c. single dose) alone, or in association with Se (0.3 mg/kg, s.c. single dose), ZnCl₂ (20 mg/kg, s.c. single dose) or both of them simultaneously. The nephrotoxic effects were monitored by the evaluation of plasma renal parameters, oxidative stress biomarkers, DNA damage, and renal Cr content. The obtained results showed that K₂Cr₂O₇ disturbed renal biochemical markers, induced oxidative stress and DNA fragmentation in kidney tissues, and altered renal histoarchitecture. The co-administration of Se and/or ZnCl₂ has exhibited pronounced chelative, antioxidant, and genoprotective effects against K₂Cr₂O₇-induced renal damage and attenuated partially the histopathological alterations. These results suggest that Se and Zn can be used as efficient nephroprotective agents against K₂Cr₂O₇-induced toxicity in pregnant Wistar Albino rats.

Rosmarinus officinalis essential oil modulates renal toxicity and oxidative stress induced by potassium dichromate in rats

BACKGROUND

Chromium hexavalent (CrVI) is known as a toxic contaminant that induced oxidative stress and nephrotoxicity in humans and animals. Rosmarinus officinalis is a perennial herb rich in biologically active constituents that have powerful antioxidant properties. So, the current work evaluated the effectiveness of Rosmarinus officinalis essential oil (REO) against alterations induced by potassium dichromate in the kidney of male rats.

METHODS

GC-MS analysis, in vitro total phenol contents, and DPPH scavenging activity of REO were estimated. Thirty-five Wistar male rats were categorized into 5 groups. The first group was the control, the second one was orally administered rosemary essential oil (REO; 0.5 mL/kg BW), the third group was injected intraperitoneally with hexavalent chromium (CrVI; 2 mg/kg BW) for 14 days, the fourth group used as the protective group (REO was administrated 30 min before i.p. injection of CrVI) and the fifth group applied as the therapeutic group (rats injected with CrVI 30 min followed by oral administration of REO), respectively.

RESULTS

Twenty-nine components were detected with high total phenolic contents and high DPPH scavenging activity. Results revealed that CrVI- intoxicated rats showed a valuable increase in oxidative stress profile (TBARS and H₂O₂) and a notable decline in glutathione (GSH), total protein content, and enzymatic antioxidants (SOD, CAT, GPx, and GST). Furthermore, serum kidney functions biomarkers (urea, creatinine, and uric acid) were increased significantly. Also, the administration of CrVI showed histological and immunohistochemical (PCNA-ir) changes in rat kidney tissue. Otherwise, administration of REO pre or post-treatment with CrVI significantly restored most of the biochemical parameters in addition to improvement in kidney tissue architecture. Moreover, individual intake with REO exhibited an amendment in oxidative stress markers.

CONCLUSION

Conclusively, REO had a potential antioxidant capacity in ameliorating K₂Cr₂O₇-induced nephrotoxicity, especially in the protection group.

Protective effects of selenium and zinc against potassium dichromate-induced thyroid disruption, oxidative stress, and DNA damage in pregnant Wistar rats

Hexavalent chromium (CrVI) is an environmental pollutant and an endocrine-disrupting metal. Se and Zn are essential trace elements, known to play a crucial role in thyroid homeostasis. However, there is a lack of data reporting thyrotoxicity during gestation. In this study, we investigated the protective effects of selenium and zinc against potassium dichromate-induced thyrotoxicity in pregnant Wistar rats. Thirty pregnant Wistar rats were divided into control and four treated groups receiving subcutaneously (s.c) on the 3rd day of pregnancy, K2Cr2O7 (10 mg/kg, s.c) alone, or in association with Se (0.3 mg/kg, s.c), ZnCl2 (20 mg/kg, s.c), or both of them simultaneously. The hormonal profile, oxidative stress biomarkers, DNA damage, and histological modifications were evaluated. Our main findings showed that K2Cr2O7 promoted hypothyroidism, oxidative stress, genotoxicity, and histological alterations in the thyroid gland. The co-treatment with Se or ZnCl2 has mitigated K2Cr2O7-induced thyrotoxicity in pregnant Wistar rats by exhibiting antioxidant and genoprotective effects. However, the combined co-treatment of both of them was less thyroprotective, and therefore, further investigations on the synergetic interaction of Se and Zn against CrVI toxicity using different doses and exposure routes are required.

Cr(VI) induces ROS-mediated mitochondrial-dependent apoptosis in neuronal cells via the activation of Akt/ERK/AMPK signaling pathway

Hexavalent chromium (Cr(VI)), a well-known toxic industrial and environmental pollutant, has been shown to cause serious toxic and health effects. However, limited information is available on Cr(VI)-induced neurotoxic potential, with the underlying toxicological mechanisms remain mostly unclear. The present study demonstrated that the mitochondria-dependent apoptosis pathway was involved in Cr(VI)-induced SH-SY5Y cell (the human neuroblastoma cell line) death, which was accompanied by the appearance of cell shrinkage, increased mitochondrial membrane potential (MMP) depolarization and cytochrome c release, and the activation of caspase cascades and poly (ADP-ribose) polymerase (PARP). Cr(VI) treatment also increased the generation of intracellular reactive oxygen species (ROS). Pretreatment of SH-SY5Y cells with antioxidant N-acetylcysteine (NAC) effectively attenuated ROS production and reversed these Cr(VI)-induced cytotoxicity and apoptotic responses. Furthermore, exposure to Cr(VI) significantly increased the phosphorylation levels of Akt, extracellular regulated kinase (ERK)1/2, and AMP-activated protein kinase (AMPK)α. NAC and the pharmacological inhibitor of Akt (LY294002), ERK1/2 (PD980590), and AMPKα (Compound C) markedly abrogated the Cr(VI)-induced activation of Akt, ERK1/2, and AMPKα signal, respectively, with the concomitant inhibition of mitochondrial dysfunction and caspase activation. Additionally, all these inhibitors suppressed Cr(VI)-induced phosphorylation of Akt, ERK1/2, and AMPKα and of each other. Collectively, these results suggest that Cr(VI) exerts its cytotoxicity on neuronal cells by inducing mitochondria-dependent apoptosis through the interdependent activation of Akt, ERK1/2, and AMPKα, which are mainly mediated by ROS generation.

Bone marrow mesenchymal stem cells repair Cr (VI)- injured kidney by regulating mitochondria-mediated apoptosis and mitophagy mediated via the MAPK signaling pathway

The present study aimed to explore the repair effect and mechanism of bone marrow mesenchymal stem cells (BMSCs) transplantation on injured kidneys caused by hexavalent chromium (Cr (VI)). Wistar rats were intraperitoneally injected with 0.4 mg/kg•bw Cr (VI) ion solution. After 30 days, 1 × 10⁷ BMSCs were transplanted into rats. After cell transplantation for 2 weeks, there was no significant difference in the chromium content between the model and BMSCs-therapy group by atomic absorption spectrometry. In BMSCs-therapy group, the renal organ index, the serum levels of blood urea nitrogen (BUN) and creatinine (CRE), malonaldehyde (MDA) content were significantly decreased, superoxide dismutase (SOD) activity was significantly elevated, and the pathological changes were improved compared with the model group. The results of immunohistochemical and western blot assays showed that the expressions of apoptosis-related proteins Bax, Cytochrome c, and Caspase-3, as well as autophagy-associated proteins Beclin 1, PINK1, Parkin, p-Parkin, LC3B, and the MAPK signaling pathway, including the ratio of p-p38 to p38 and p-JNK to JNK were all significantly decreased, Bcl-2 and p62 expressions, and the ratio of p-ERK to ERK were significantly elevated in BMSCs-therapy group compared with the model group. These results suggested that BMSCs repaired Cr (VI)-injured kidney through decreasing mitochondria-mediated apoptosis and mitophagy mediated by downregulating phosphorylation of p38 and JNK, upregulating phosphorylation of ERK.