Carnosine and N-acetyl cysteine protect against sodium nitrite-induced oxidative stress in rat blood

Progress in the Use of Hydrogels for Antioxidant Delivery in Skin Wounds

The skin is the largest organ of the body, and it acts as a protective barrier against external factors. Chronic wounds affect millions of people worldwide and are associated with significant morbidity and reduced quality of life. One of the main factors involved in delayed wound healing is oxidative injury, which is triggered by the overproduction of reactive oxygen species. Oxidative stress has been implicated in the pathogenesis of chronic wounds, where it is known to impair wound healing by causing damage to cellular components, delaying the inflammatory phase of healing, and inhibiting the formation of new blood vessels. Thereby, the treatment of chronic wounds requires a multidisciplinary approach that addresses the underlying causes of the wound, provides optimal wound care, and promotes wound healing. Among the promising approaches to taking care of chronic wounds, antioxidants are gaining interest since they offer multiple benefits related to skin health. Therefore, in this review, we will highlight the latest advances in the use of natural polymers with antioxidants to generate tissue regeneration microenvironments for skin wound healing.

Acrolein induces mitochondrial dysfunction and insulin resistance in muscle and adipose tissues in vitro and in vivo

Type 2 diabetes mellitus (DM) is a common chronic condition characterized by persistent hyperglycemia and is associated with insulin resistance (IR) in critical glucose-consuming tissues, including skeletal muscle and adipose tissue. Oxidative stress and mitochondrial dysfunction are known to play key roles in IR. Acrolein is a reactive aldehyde found in the diet and environment that is generated as a fatty acid product through the glucose autooxidation process under hyperglycemic conditions. Our previous studies have shown that acrolein impairs insulin sensitivity in normal and diabetic mice, and this effect can be reversed by scavenging acrolein. This study demonstrated that acrolein increased oxidative stress and inhibited mitochondrial respiration in differentiated C2C12 myotubes and differentiated 3T3-L1 adipocytes. As a result, insulin signaling pathways were inhibited, leading to reduced glucose uptake. Treatment with acrolein scavengers, N-acetylcysteine, or carnosine ameliorated mitochondrial dysfunction and inhibited insulin signaling. Additionally, an increase in acrolein expression correlated with mitochondrial dysfunction in the muscle and adipose tissues of diabetic mice. These findings suggest that acrolein-induced mitochondrial dysfunction contributes to IR, and scavenging acrolein is a potential therapeutic approach for treating IR.

Glycyrrhizic acid ameliorates sodium nitrite-induced lung and salivary gland toxicity: Impact on oxidative stress, inflammation and fibrosis

Despite wide application of sodium nitrite (SN) as food additive, it exhibits considerable side effects on various body organs at high dose or chronic exposure. The aim of this study was to test whether Glycyrrhizic acid (GA) could ameliorate SN-induced toxicity in lung and submandibular salivary gland (SMG). A sample size of 30 adult male albino rats was randomly allocated into 3 groups. Group 1 served as control group. Rats were treated orally with 80 mg/kg of SN in group 2 or SN preceded by (15 mg/kg) GA in group 3. Lung & SMG tissues were used for oxidative stress assessment, examination of histopathological changes, fibrosis (MTC, TGF-β and α-SMA) and inflammation (TNF-α, IL-1β and CD-68). Concurrent administration of GA ameliorated pulmonary and salivary SN-induced toxicity via restoring the antioxidant defense mechanisms with reduction of MDA levels. GA reduced the key regulators of fibrosis TGF-β and α-SMA and collagen deposition. In addition to reduction of inflammatory cytokine (TNF-α, IL-1β) and macrophages recruitments, GA amended both pulmonary and salivary morphological changes. The present study proposed GA as a promising natural herb with antioxidant, anti-inflammatory and antifibrotic effects against pulmonary and salivary SN-induced toxicity.

Antioxidant biocompatible composite collagen dressing for diabetic wound healing in rat model

Associated with persistent oxidative stress, altered inflammatory responses, poor angiogenesis and epithelization, wound healing in diabetic patients is impaired. N-acetylcysteine (NAC) is reported to resist excess reactive oxygen species (ROS) production, prompt angiogenesis and maturation of the epidermis. Studies have revealed that graphene oxide (GO) can regulate cellular behavior and form cross-links with naturally biodegradable polymers such as collagen (COL) to construct composite scaffolds. Here, we reported a COL-based implantable scaffold containing a mixture of GO capable of the sustained delivery of NAC to evaluate the wound healing in diabetic rats. The morphological, physical characteristics, biocompatibility and NAC release profile of the GO-COL-NAC (GCN) scaffold were evaluated in vitro. Wound healing studies were performed on a 20 mm dorsal full-skin defect of streptozotocin (STZ)-induced diabetic rats. The injured skin tissue was removed at the 18th day post-surgery for histological analysis and determination of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) activity. In diabetic rats, we confirmed that the GCN scaffold presented a beneficial effect in enhancing the wound healing process. Additionally, due to the sustained release of NAC, the scaffold may potentially induce the antioxidant defense system, upregulating the expression levels of the antioxidant enzymes in the wound tissue. The findings revealed that the antioxidant biocompatible composite collagen dressing could not only deliver NAC in situ for ROS inhibition but also promote the wound healing process. This scaffold with valuable therapy potential might enrich the approaches for surgeon in diabetic wound treatment in the future.

Hydrogen Sulfide and Carnosine: Modulation of Oxidative Stress and Inflammation in Kidney and Brain Axis

Emerging evidence indicates that the dysregulation of cellular redox homeostasis and chronic inflammatory processes are implicated in the pathogenesis of kidney and brain disorders. In this light, endogenous dipeptide carnosine (β-alanyl-L-histidine) and hydrogen sulfide (H₂S) exert cytoprotective actions through the modulation of redox-dependent resilience pathways during oxidative stress and inflammation. Several recent studies have elucidated a functional crosstalk occurring between kidney and the brain. The pathophysiological link of this crosstalk is represented by oxidative stress and inflammatory processes which contribute to the high prevalence of neuropsychiatric disorders, cognitive impairment, and dementia during the natural history of chronic kidney disease. Herein, we provide an overview of the main pathophysiological mechanisms related to high levels of pro-inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and neurotoxins, which play a critical role in the kidney–brain crosstalk. The present paper also explores the respective role of H₂S and carnosine in the modulation of oxidative stress and inflammation in the kidney–brain axis. It suggests that these activities are likely mediated, at least in part, via hormetic processes, involving Nrf2 (Nuclear factor-like 2), Hsp 70 (heat shock protein 70), SIRT-1 (Sirtuin-1), Trx (Thioredoxin), and the glutathione system. Metabolic interactions at the kidney and brain axis level operate in controlling and reducing oxidant-induced inflammatory damage and therefore, can be a promising potential therapeutic target to reduce the severity of renal and brain injuries in humans.

Mechanism underlying nephroprotective property of curcumin against sodium nitrite-induced nephrotoxicity in male Wistar rat

The current work examined the outcome of curcumin (20 mg/kg body weight/day) administration on arginase and adenosine deaminase (ADA) activities and other kidney markers, as well as markers of oxidative stress, in Wistar rats exposed to sodium nitrite (NaNO₂ ) (60 mg/kg of body weight, single dose) for 28 days. The results revealed that the NaNO₂ exposed rats had significantly altered the ADA activities, arginase activities alongside other biomarkers of kidney function, and oxidative stress. However, pretreatment with curcumin significantly mitigated the altered activities ADA and arginase as well as other parameters. This was supported by the histopathological examination of the kidney tissues. Our findings suggest that the alteration in the activities of ADA and arginase could be involved in the mechanism of action employed by NaNO₂ and curcumin in the respective induction and prevention of nephrotoxicity. PRACTICAL APPLICATIONS: These results suggest that moderate exposure to the acceptable daily dose of curcumin can improve food-related kidney damage through regulations of ADA and arginase activities, enhancement in the antioxidant system, and suppression of lipid peroxidation.