Poly (ADP-Ribose) polymerase-1 (PARP-1) overactivity plays a pathogenic role in bile acids-induced nephrotoxicity in cholestatic rats.

Cholestatic liver disease is a clinical complication with a wide range of etiologies. The liver is the primary organ influenced by cholestasis. Other organs, rather than the liver (e.g., kidneys), could also be affected by cholestatic liver disease. Cholestasis-induced renal injury is known as cholemic nephropathy (CN). Although the structural and functional alterations of the kidney in cholestasis have been well described, the cellular and molecular mechanisms of CN are not well understood. Some studies mentioned the role of oxidative stress and mitochondrial impairment in CN. Several cellular targets, including proteins, lipids, and DNA, could be affected by oxidative stress. Poly (ADP-Ribose) polymerase-1 (PARP-1) is an enzyme that its physiological activity plays a fundamental role in DNA repair. However, PARP-1 overexpression is associated with enhanced oxidative stress and cell death. The current study was designed to evaluate the role of PARP-1 activity in the pathogenesis of CN. Bile duct ligated (BDL) rats were treated with nicotinamide (NA) as a PARP-1 inhibitor. Kidney, urine, and plasma samples were collected at scheduled time intervals (3, 7, 14, and 28 days after BDL surgery). Serum and urine biomarkers of kidney injury, markers of oxidative stress and DNA damage, PARP-1 expression and activity in the kidney tissue, inflammatory response, renal fibrosis markers, and kidney histopathological alterations were assessed. Significant changes in the serum and urine biomarkers of kidney injury were evident in the BDL rats. Markers of oxidative stress were increased, and tissue ATP levels and antioxidant capacity were decreased in the kidney of cholestatic animals. A significant increase in PARP-1 expression and activity was evident in BDL rats (3, 7, 14, and 28 days after BDL). Moreover, inflammatory response (IL-1ß and TNF-α expression; and myeloperoxidase activity), renal tissue histopathological alterations, and kidney fibrosis (α-SMA and TGF-ß expression, as well as collagen deposition) were detected in cholestatic animals. It was found that the PARP-1 inhibitor, NA (50 and 100 mg/kg, i.p), significantly mitigated cholestasis-induced renal injury. The positive effects of NA were more significant at a lower dose and the early stage of CN. These data indicate a pathogenic role for PARP-1 overexpression in CN.

Hormesis Effects of Nano- and Micro-sized Copper Oxide.

The concerns about the possible risk of manufactured nanoparticles (NPs) have been raised recently. Nano- and micro-sized copper oxide (CO and CONP) are widely used in many industries. In this regard, in-vitro studies have demonstrated that CONP is a toxic compound in different cell lines. Despite their unique properties, NPs possess unexpected toxicity profiling relative to the bulk materials. This study was designed to examine and compare the toxic effects of CO and CONPs in-vivo and in isolated rat mitochondria. Male Wistar albino rats received 50 to 1000 mg/kg CO or CONP by gavage and several toxicological endpoints including biochemical indices and oxidative stress markers. Then, the pathological parameters in the multiple organs such as liver, brain, spleen, kidney, and intestine were assessed. Mitochondria were isolated from the rat liver and several mitochondrial indices were measured. The results of this study demonstrated that CO and CONP exhibited biphasic dose-response effects. CONPs showed higher toxicity compared with the bulk material. There were no significant changes in the results of CONP and CO in isolated rat liver mitochondria. The present studies provided more information regarding the hormetic effects of CO and CONPs in-vivo and in isolated rat mitochondria.

Mitochondrial dysfunction as a mechanism involved in the pathogenesis of cirrhosis-associated cholemic nephropathy.

Cholemic nephropathy (CN) is a clinical complication associated with cholestasis and chronic liver diseases. CN could lead to renal failure and the need for kidney transplantation if not appropriately managed. On the other hand, although the clinical features of CN are well described, there is no clear idea on the precise cellular and molecular mechanisms of CN. The current study was designed to evaluate kidney mitochondrial function in cholestasis-associated CN. Rats underwent bile duct ligation (BDL) surgery, and kidney mitochondria were isolated at scheduled time intervals (14, 28, and 42 days after BDL operation). Several mitochondrial indices including mitochondrial permeabilization and swelling, glutathione and ATP content, mitochondrial depolarization, and lipid peroxidation were evaluated. Renal tissue markers of oxidative stress along with tissue histopathological changes and serum biochemistry were also analyzed. Severe kidney tissue histopathological alterations including interstitial inflammation, necrosis, and Bowman capsule dilation were detected in the BDL animals. Moreover, drastic elevation in renal fibrosis and collagen deposition was detected in BDL rats. Oxidative stress markers were also significantly enhanced in the kidney tissue of BDL animals. On the other hand, it was found that mitochondrial indices of functionality were significantly deteriorated in BDL rats. These data introduce mitochondrial dysfunction and energy metabolism disturbances as a fundamental mechanism involved in the pathogenesis of bile acids-associated renal injury during cholestasis.

Diazinon Interrupts Ovarian Steroidogenic Acute Regulatory (StAR) Gene Transcription in Gonadotropin-Stimulated Rat Model.

Organophosphate pesticides are considered as endocrine disruptors that interfere with reproductive functions. The corpus luteum (CL) is a transient endocrine gland that produces progesterone, a crucial hormone for a successful beginning and maintenance of pregnancy. Steroidogenic acute regulatory protein (StAR) facilitates the rate-limiting transfer of cholesterol from the outer mitochondrial membrane to the inner organelle membranes. We investigated the effect of Diazinon (DZN), an organophosphate, on StAR mRNA expression by Sybergreen Real Time-PCR in a time-dependent manner in luteal phase. Fifty immature female Wistar rats (24-day-old) were injected with a single injection of Pregnant mare's Serum Gonadotropin (PMSG) followed by a single injection of human Chorionic Gonadotropin (hCG), 48 h later. Then, DZN was administered in a single dose (70 mg/kg bw, I.P), controls received only the vehicle, 12 h post-hCG injection. Ovaries were collected in 4 h. intervals from 8 to 24 h post-hCG injection. Then, hCG stimulation transcript levels of StAR gene were significantly altered in the hormone-stimulated rats following DZN treatment. In addition, histological study showed that the CL diameter in DZN-treated group was smaller than control group (p = 0.000). Our findings suggest that the critical step in the function of CL is disrupted by DZN and may correlates with female reproductive damage.

Betaine treatment protects liver through regulating mitochondrial function and counteracting oxidative stress in acute and chronic animal models of hepatic injury.

Betaine is a derivative of the amino acid glycine widely investigated for its hepatoprotective properties against alcoholism. The protective properties of betaine in different other experimental models also have been documented. On the other hand, the exact cellular mechanism of cytoprotection provided by betaine is obscure. The current study was designed to evaluate the hepatoprotective effects of betaine and its potential mechanisms of hepatoprotection in two animal models of acute and chronic liver injury. Bile duct ligation (BDL) was used as a model of chronic liver injury and thioacetamide (TAA)-induced hepatotoxicity was applied as the acute liver injury model. Severe increase in serum markers of liver tissue damage along with significant liver tissue histopathological changes were evident in both acute and chronic models of hepatic injury. It was also found that tissue markers of oxidative stress were significantly increased in BDL and TAA-treated animals. Moreover, liver mitochondrial indices of functionality were deteriorated in both investigated models. Betaine supplementation (10 and 50 mg/kg, i.p) ameliorated hepatic injury as judged by decreased liver tissue histopathological alterations, a significant decrease in tissue markers of oxidative stress, and mitigation of serum biomarkers of hepatotoxicity. On the other hand, betaine (10 and 50 mg/kg, i.p) protected hepatocytes mitochondria in both chronic and acute models of hepatotoxicity. These data indicate that the antioxidative and mitochondria regulating properties of betaine could play a primary role in its mechanisms of hepatoprotection.

Effects of sodium benzoate, a commonly used food preservative, on learning, memory, and oxidative stress in brain of mice.

Sodium benzoate (SB) is a widely used preservative and antimicrobial substance in many foods and soft drinks. However, this compound is generally recognized as safe food additives, but evidence has suggested that a high intake of SB may link to attention deficit-hyperactivity disorder in children. Present study investigate the effects of oral administration of different concentrations of SB (0.56, 1.125, and 2.25 mg/mL) for 4 weeks, on the learning and memory performance tests, and also the levels of malondialdehyde (MDA), reduced glutathione (GSH), and acetylcholinesterase activity (AChE) in the mouse brain. The results showed that SB significantly impaired memory and motor coordination. Moreover, SB decreased reduced GSH and increased the MDA level in the brain significantly (P < 0.001). However, nonsignificant alteration was observed in the AChE activity. These findings suggest that short-term consumption of SB can impair memory performance and increased brain oxidative stress in mice.