Regulation of radiation-induced liver damage by modulation of SIRT-1 activity: In vivo rat model

The role of sirtuin1 in liver injury: molecular mechanisms and novel therapeutic target

Liver disease is a common and serious threat to human health. The progression of liver diseases is influenced by many physiologic processes, including oxidative stress, inflammation, bile acid metabolism, and autophagy. Various factors lead to the dysfunction of these processes and basing on the different pathogeny, pathology, clinical manifestation, and pathogenesis, liver diseases are grouped into different categories. Specifically, Sirtuin1 (SIRT1), a member of the sirtuin protein family, has been extensively studied in the context of liver injury in recent years and are confirmed the significant role in liver disease. SIRT1 has been found to play a critical role in regulating key processes in liver injury. Further, SIRT1 seems to cause divers outcomes in different types of liver diseases. Recent studies have showed some therapeutic strategies involving modulating SIRT1, which may bring a novel therapeutic target. To elucidate the mechanisms underlying the role of sirtuin1 in liver injury and its potentiality as a therapeutic target, this review outlines the key signaling pathways associated with sirtuin1 and liver injury, and discusses recent advances in therapeutic strategies targeting sirtuin1 in liver diseases.

Evaluation of the Reparative Effect of Sinomenine in an Acetaminophen-Induced Liver Injury Model

Due to its rising global prevalence, liver failure treatments are urgently needed. Sinomenine (SIN), an alkaloid from sinomenium acutum, is being studied for its liver-repair properties due to Acetaminophen (APAP) overdose. SIN's effect on APAP-induced hepatotoxicity in rats was examined histologically and biochemically. Three groups of 30 adult male Wistar rats were created: control, APAP-only, and APAP + SIN. Histopathological and biochemical analyses were performed on liver samples after euthanasia. SIN is significantly protected against APAP damage. Compared to APAP-only, SIN reduced cellular injury and preserved hepatocellular architecture. The APAP + SIN Group had significantly lower ALT, MDA, and GSH levels, protecting against hepatocellular damage and oxidative stress. SIN also had dose-dependent antioxidant properties. When examining critical regulatory proteins, SIN partially restored Sirtuin 1 (SIRT1) levels. While BMP-7 levels were unaffected, histopathological evidence and hepatocyte damage percentages supported SIN's liver-restorative effect. SIN protected and repaired rats' livers from APAP-induced liver injury. This study suggests that SIN may treat acute liver damage, warranting further research into its long-term effects, optimal dosage, and clinical applications. These findings aid liver-related emergency department interventions and life-saving treatments.

The senomorphic impact of astaxanthin on irradiated rat spleen: STING, TLR4 and mTOR contributed pathway

OBJECTIVES

Exposure of spleen tissues to ionizing radiation during radiotherapy can induce cellular stress and immune-dysfunction leading to cellular senescence.

INTRODUCTION

The process of a cancerous development is facilitated by the accumulation of senescent cells. This justifies the incorporation of anti-senescent medications during splenic irradiation (SI).

METHODS

In this study senescence was induced in the spleen of male albino rats by radiation exposure (5Gy-single whole body gamma-irradiation) then after 2 weeks, oral astaxanthin regimen was started once daily in a dose of 25 mg/kg for 7 consecutive days. Concurrent control groups were carried out.

RESULTS

the present data reflected that irradiation provoked an increase in the oxidative stress biomarkers (nitric oxide, lipid peroxidation and total reactive oxygen species levels)and the inflammatory biomarkers (Myeloperoxidase and interleukin-6). In addition irradiation led to the over expression of stimulator of interferon genes (cGAS-STING), mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) along with the lactate dehydrogenase (LDH), cyclin-dependent kinase inhibitor 1 (p21) cyclin-dependent kinase inhibitor 2A (p16) increment with elevation of tumor suppressor protein (p53) level. However, reduced glutathione contents and catalase activity were reduced post irradiation in spleen tissues, all these changes reflecting induction of cellular senescence. Astaxanthin treatment showed an improvement in the antioxidant/oxidative stress balance, inflammatory biomarkers, histopathological examination and immunohistochemical expressions of the tested proteins in the irradiated rats.

CONCLUSION

the current findings offer a new insight into the senomorphic effect of astaxanthin following radiation-induced spleen senescence via STING, mTOR, and TLR4 signalling pathways.

The protective effect of crocin against testicular toxicity induced by ionizing radiation via AKT/FOXO pathway

Crocin, a pharmacologically active component of Crocus sativus L. (saffron), has been informed to be beneficial in the treatment of stress-related oxidative impairment. In the present study, we examined the protective role of crocin against testicular damage induced by radiation (acute and fractionated) and the alteration of the AKT/FOXO signaling pathway. Male Wister albino rats were exposed to acute dose of 6 Gy and a fractionated dose of gamma radiation (2 Gy every 2 days up to 6 Gy total doses). Rats were pretreated intraperitoneally with crocin in a dose of 50 mg/kg for seven consecutive days prior to exposure to irradiation at a level of 6 Gy and during the fractionated irradiation of rats. Control groups were run concurrently. Ionizing radiation caused changes in the level of oxidative stress biomarkers manifested as elevation of thiobarbituric acid reactive substance, total nitrate/nitrite and reactive oxygen species (ROS) associated with a decrease in catalase as well as in the level of inflammatory parameters (decrease in expression of Nrf2 which was related to a significant increase in expression of NF-κB p65). Irradiation produced cellular damage characterized by an increase in serum lactate dehydrogenase. These findings were aligned with increased expression of the forkhead box O-1 (FOXO-1) and activation of protein kinase B (AKT) pathway. Irradiation of rats led to reduction in serum testosterone level and testicular weights. Pretreatment with the indicated dose of crocin shielded against the changes in all the evaluated parameters. Administration of crocin can be introduced as a novel preclinical approach for regulation of testicular damage induced by radiation; via controlling the ongoing oxidative stress and inflammatory reaction as well as activation FOXO/AKT signaling pathway.

Photoelectrochemical Biosensor for Histone Deacetylase Sirt1 Detection Based on Polyaspartic Acid-Engaged and Triggered Redox Cycling Amplification and Enhanced Photoactivity of BiVO4 by Gold Nanoparticles and SnS2

A photoelectrochemical (PEC) biosensor was established for histone deacetylase Sirt1 detection based on the polyaspartic acid (PASP)-mediated redox cycling amplification and Sirt1 catalysis deacetylation-triggered recognition of the deacetylated substrate peptide, using PASP as the recognition reagent. After BiVO₄ was composited with gold nanoparticles and SnS₂, the photoactivity of the composite was greatly enhanced due to the matched energy band structure. Under the catalysis of Sirt1 enzyme, the acetylated substrate peptide was deacetylated to obtain a positive peptide, which was recognized by negative PASP. In addition to the recognition function, PASP also played other triple roles. First, PASP interacted with the positive peptide to form a double-stranded structure, which led to the electrode interface changing from irregular to regular, resulting in an improved PEC response. Second, PASP was involved into redox cycle amplification due to its reduction to dehydroascorbic acid. Further, it was used for repeated preparation of ascorbic acid to provide electron donors. This process enhanced the PEC response. Third, based on the matched energy band with BiVO₄, PASP effectively improved the photoactivity of BiVO₄. With multiplex signal amplification, the PEC biosensor showed a wide linear range (1.83-1830 pM) and high detection sensitivity with a low detection limit of 0.732 pM (S/N = 3). The applicability of this method was evaluated by studying the effects of a known inhibitor of nicotinamide and the heavy metal ions of Cd²⁺ and Pb²⁺ on Sirt1 enzyme activity, and the results showed that this method not only provided a new platform for screening Sirt1 enzyme inhibitors but also provided new biomarkers for evaluating the ecotoxicological effects of environmental pollutants.