The Potential Protective Effect of Curcumin and α-Lipoic Acid on N-(4-Hydroxyphenyl) Acetamide-induced Hepatotoxicity Through Downregulation of α-SMA and Collagen III Expression

Background and objectives

N-(4-hydroxyphenyl) acetamide (NHPA) is the most commonly used analgesic and antipyretic agent worldwide; however, it remains the leading cause of drug-induced acute liver failure. This study explored the potential impact of curcumin (Curc) and/or α-lipoic acid (Lip acid) on liver damage induced by NHPA overdose.

Materials and Methods

Male Wistar rats were intoxicated with a single oral dose of NHPA (1000 mg/kg) and treated with Curc (200 mg/kg p. o.) and/or Lip acid (100 mg/kg i. p.). These treatments were given in 2 doses at 2 hours and 10 hours post-NHPA-administration. Animals were sacrificed 24 hours post-NHPA-administration.

Results

Treatment with Curc and/or Lip acid showed effective reduction of NHPA-induced liver injury, demonstrated by reducing serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, as well as hepatic nitric oxide and malondialdehyde. Curc and/or Lip acid treatments counteracted these changes. They also ameliorated NHPA-induced centrilobular hepatocellular necrosis, evidenced by histopathological examination. Moreover, Curc and Lip acid reduced the expression of alpha-smooth muscle actin and collagen III, upregulated by NHPA intoxication in response to oxidative stress and inflammation.

Discussion and Conclusion

Curc and Lip acid can be considered as promising natural therapies against liver injury, induced by NHPA, through their antioxidant and antifibrotic actions.

The inhibitory mechanisms of losartan and vitamin D on amiodarone-induced lung inflammation in rats: Role of mitogen-activated protein kinases/activator protein-1

Amiodarone (AMD), an antiarrhythmic drug, is used cautiously due to its lung toxicity that is characterized by alveolar inflammation followed by fatal fibrosis. AMD induces lung inflammation via increasing the alveolar macrophages and disturbing the balance of T-helper-1 (Th1) and Th2 cells cytokines. In this study, the role of the mitogen-activated protein kinases (MAPKs)/activator protein-1 (AP-1) pathway in AMD-induced lung inflammation was evaluated. Also, the anti-inflammatory and antifibrotic effects of losartan and/or vitamin D were investigated following 7, 14, and 28 days of AMD administration. AMD resulted in lung injury, inflammatory infiltration, and increased pulmonary levels of inflammatory cytokines starting from Week 1 of exposure. A significant increase in serum levels of interleukin-4 along with a significant reduction of interferon-gamma, in addition to strong expression of CD68, were reported after 14 and 28 days of AMD administration reflecting Th1/Th2 cytokines imbalance and the accumulation of alveolar macrophages, respectively. The phosphorylation of MAPKs (ERK1/2, JNK, p38) and AP-1 was significantly enhanced starting from Week 1 of exposure. Marked expression of transforming growth factor beta-1 and massive deposition of collagen were detected after 28 days reflecting late fibrosis. All these abnormalities were significantly mitigated by vitamin D and its combination with losartan. Losartan alone has less prominent anti-inflammatory effects particularly after 28 days; however, it efficiently prevented late fibrosis. This study concludes that MAPKs/AP-1 pathway is involved in AMD-induced lung inflammation and that vitamin D and/or losartan could be used as a prophylactic agent to prevent AMD-induced lung toxicity.

Role of some natural anti-oxidants in the down regulation of Kim, VCAM1, Cystatin C protein expression in lead acetate-induced acute kidney injury

BACKGROUND

Lead is a dangerous systemic toxicant and can provoke life-threatening renal injury. The plan of this study was to evaluate the potential impact of curcumin (CRMN) and L-ascorbic acid (L-ascb) alone or together to counteract lead acetate (Pb-acetate)-induced renal damage in rats and to find out the underlying mechanisms of action of these nutraceuticals.

METHODS

Pb-acetate (100 mg/kg/day, i.p.) was injected in male rats along with L-ascb (250 mg/kg/day) and/or CRMN (200 mg/kg/day) orally for 7 days.

RESULTS

Pb-acetate administration increased serum urea, creatinine and uric acid. Renal tissue showed a marked depletion in reduced glutathione level and superoxide dismutase activity and elevation in nitric oxide and malondialdehyde levels. Serum C-reactive protein and IL-1β levels were elevated. Up-regulation of the expression of kidney injury molecule, vascular adhesion molecule-1 and Cystatin C were noticed after Pb-acetate administration. DNA fragmentation was also increased in renal tissues. Histopathological examination revealed a destructed partial layer of Bowman's capsule, proximal and distal convoluted tubules. Treatment with the aforementioned antioxidants ameliorated most of the altered measured biomarker levels.

CONCLUSION

Interestingly, the combination of L-ascb and CRMN showed the superlative protective effect against Pb-acetate-induced nephrotoxicity.

N-glycosylation and expression in human tissues of the orphan GPR61 receptor

A number of members of the G protein-coupled receptor class of cell surface receptors are 'orphans' with no known endogenous ligand. One of these orphan receptors is GPR61; there are little data about its expression in human cells and tissues. In this study, we investigated the post-translational modification of GPR61 by N-glycosylation at an identified consensus N-glycosylation site (N12) and the impact of this modification upon the subcellular expression of the protein. The N-glycosylation inhibitor tunicamycin reduced the apparent molecular weight of immunoreactivity associated with myc-tagged GPR61 by 1-2 kDa, which was comparable to the evident molecular weight of the myc-tagged N12S GPR61 mutant with disrupted consensus N-glycosylation site. Analysis of GPR61 expression demonstrated that tunicamycin treatment reduced considerably heterologous expression of GPR61 in the cell membrane despite the N12S GPR61 mutant being readily expressed at the cell surface. These results demonstrate that GPR61 is subject to N-glycosylation but suggest this is not a prerequisite for cell surface expression, although N-glycosylation of other proteins may be important for cell membrane expression of GPR61. Expression of GPR61 protein was demonstrated at the cellular level in human hippocampus and human peripheral blood mononuclear cells. In the latter, there was a significantly higher expression of GPR61 in the Th17 cell subset in comparison with resting CD4+ cells, which may point toward a potential role for the GPR61 receptor in autoimmune diseases. This is the first report that GPR61 protein is subject to post-translational modification and is expressed in immune cell subsets and the hippocampus. These findings will help guide studies to investigate the function of GPR61.