Investigation of the anti-oxidative and anti-inflammatory effects of melatonin on experimental liver damage by radiation

Intravitreal melatonin for the prevention of radiation retinopathy: a step beyond bevacizumab

PURPOSE

Intravitreal bevacizumab has been utilized to mitigate radiation retinopathy, yet the potential role of intravitreal melatonin for its prevention remains unexplored. This study aims to evaluate and compare the efficacy of intravitreal melatonin and bevacizumab in preventing radiation retinopathy in an experimental animal model.

MATERIALS AND METHODS

Twelve healthy male New Zealand white rabbits (n = 24 eyes) received a single 3000 cGy irradiation dose in both eyes. Intravitreal melatonin (100 mcg/kg = 300 mcg/0.05 mL) was administered to the left eyes of six rabbits, and bevacizumab (1.25 mg/0.05 mL) to the left eyes of the remaining six, with sham injections given to the right eyes as controls. Six weeks after irradiation, bilateral enucleation was performed for biochemical and histopathological evaluation.

RESULTS

Oxidative stress markers did not differ significantly between the groups (p = .827). Both melatonin and bevacizumab treatments markedly reduced axonal damage compared to the sham control group (p < .001). Melatonin also demonstrated a trend toward superior neuroprotective effects relative to bevacizumab, though this difference was not statistically significant (p = .07).

CONCLUSIONS

Intravitreal melatonin demonstrated efficacy comparable to bevacizumab in reducing radiation-induced retinopathy, with an encouraging trend toward enhanced neuroprotection. These findings position melatonin as a potential novel therapeutic for radiation retinopathy prophylaxis. Further research with larger, long-term studies is warranted to validate these results and investigate melatonin's broader applications in retinal protection.

Enhanced kidney damage induced by increasing nonylphenol doses: impact on autophagy-related proteins and proinflammatory cytokines in rats

Nonylphenol (NP) is an organic pollutant and endocrine disruptor chemical that has harmful effects on the environment and living organisms. This study looked at whether kidney tissues subjected to increasing doses of nonylphenol generated alterations in histopathologic, pro-inflammatory, and autophagic markers. Fifty rats were divided into five groups of ten each: group I: healthy group, II: control (corn oil), group III: 25 μl/kg NP, group IV: 50 μl/kg NP, group V: 75 μl/kg NP. The kidney tissue samples were obtained for histopathological, immunohistochemical, and biochemical analyses. The histological deteriorations observed in all NP groups included tubular epithelial cell degeneration, inflammation areas, and hemorrhage. The immunohistochemical investigations showed that NP significantly elevated the autophagy markers (Beclin-1, LC3A/B, p62), pro-inflammatory cytokines (TNF-α, IL-6), HIF-1α, and eNOS in group III, IV and V compared with group I and II. The biochemical analysis also revealed that pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) increased in correlation with the NP doses, but only IL-1β reached statistical significance in NP treated rats kidney tissue. The biochemical findings have been confirmed by the histological studies. The damage to renal tissue caused by NP exposure may worsen it by increasing inflammatory and autophagic markers.

The Influence of Oxidative Stress Markers in Patients with Ischemic Stroke

Stroke is the second leading cause of death worldwide, and its incidence is rising rapidly. Acute ischemic stroke is a subtype of stroke that accounts for the majority of stroke cases and has a high mortality rate. An effective treatment for stroke is to minimize damage to the brain's neural tissue by restoring blood flow to decreased perfusion areas of the brain. Many reports have concluded that both oxidative stress and excitotoxicity are the main pathological processes associated with ischemic stroke. Current measures to protect the brain against serious damage caused by stroke are insufficient. For this reason, it is important to investigate oxidative and antioxidant strategies to reduce oxidative damage. This review focuses on studies assessing the concentration of oxidative stress biomarkers and the level of antioxidants (enzymatic and non-enzymatic) and their impact on the clinical prognosis of patients after stroke. Mechanisms related to the production of ROS/RNS and the role of oxidative stress in the pathogenesis of ischemic stroke are presented, as well as new therapeutic strategies aimed at reducing the effects of ischemia and reperfusion.

Melatonin mitigated methotrexate-induced hepatotoxicity through interrelated biological processes

BACKGROUND

Hepatotoxicity associated with methotrexate (MTX) is mainly due to disruption of redox balance and development of oxidative injury to hepatocytes. Melatonin (MLT) is a potent antioxidant and regulates wide range of biological functions, processes and utilized as adjuvant for number of medical applications. The current study investigated the mitigating effect of MLT on the MTX-induced hepatotoxicity.

METHODS AND RESULTS

Adult male rats received MLT (25 mg/kg, orally) for seven days flowed by single injection of MTX (20 mg/kg, ip) then treat with MLT continued for additional 7 days. The present result showed MLT treatment mitigated histopathological changes in the liver that associated with normalization of ALT and AST activity as well as bilirubin, albumin and alfa-fetoprotein levels in serum of MLT + MTX-treated rat to comparable control level. MLT treatment significantly reduced MDA content and myeloperoxidase activity while enhanced the activity of superoxide dismutase, catalase and glutathione content in the liver indicating the empowerment of the antioxidant status. Amelioration of MLT-induced oxidative stress resulted in a reduction in the inflammatory response due to antioxidant restoration and inhibited apoptosis indicated by downregulation of caspase-3 expression. The replenishment of antioxidant content powers the defense system of the hepatocytes. As a result, apoptosis is reduced which might be due to the ability of MLT protect DNA integrity thus maintaining hepatocyte functions and structure. Consequently, liver histology was protected.

CONCLUSIONS

In summary, MLT modulates liver function and structure by orchestrating linked processes, including redox balance, inflammatory response, suppression of caspase-3, and DNA damage.

Protective Effects of Boric Acid Taken in Different Ways on Experimental Ovarian İschemia and Reperfusion

Ovarian ischemia is a gynecological emergency that occurs as a result of ovarian torsion, affects women of reproductive age, and reduces ovarian reserve. The current study was designed to investigate the effect of boric acid taken in different ways on histopathological changes, autophagy, oxidative stress, and DNA damage caused by ischemia and reperfusion in the ovary of adult female rats. We established seven groups of 70 adult female rats: untreated control, intraperitoneal boric acid group (IpBA), oral boric acid group (OBA), ischemia/reperfusion group (ischemia/2 h reperfusion; OIR), ischemia/reperfusion and local boric acid group (OIR + LBA), ischemia/reperfusion and intraperitoneal boric acid group (OIR + IpBA), and ischemia/reperfusion and oral boric acid group (OIR + OBA). On the 31st day of the experimental procedure, both ovaries were harvested for histologic (hematoxylen and eosin and Masson trichrom), biochemical (ELISA and AMH, MDA, SOD, and CAT analyses), and comet evaluation. In the OIR group, hemorrhage, edema, inflammation, and diminished follicle reserve were seen in the ovary. Boric acid treatment reduced the ovarian ischemia/reperfusion damage, and the follicles exhibited similar morphological features to the control group. Moreover, boric acid treatment decreased the levels of Hsp70, NF-KB, COX-2, and CD31, which increased as a result of OIR. On the other hand, SCF and AMH levels, which decreased as a result of OIR, increased with boric acid treatment. The levels of autophagy markers (Beclin-1, LC3, and p62) reached values close to those of the control group. According to the biochemical findings, it was concluded that boric acid is also effective on oxidative stress, and the AMH level was particularly high in the OIR + OBA group, consistent with the immunohistochemical staining result. In addition, it was observed that the DNA damage caused by OIR reached values close to those of the control group, especially in the OBA after OIR. This study showed the therapeutic effects of boric acid on OIR injuries; thus, boric acid may be a potential therapeutic agent for ovarian protection and fertility preservation in cases that may cause ovarian torsion.

Potential of melatonin to reverse epigenetic aberrations in oral cancer: new findings

It is now an accepted principle that epigenetic alterations cause cellular dyshomeostasis and functional changes, both of which are essential for the initiation and completion of the tumor cycle. Oral carcinogenesis is no exception in this regard, as most of the tumors in the different subsites of the oral cavity arise from the cross-reaction between (epi)genetic inheritance and the huge challenge of environmental stressors. Currently, the biochemical machinery is put at the service of the tumor program, halting the cell cycle, triggering uncontrolled proliferation, driving angiogenesis and resistance to apoptosis, until the archetypes of the tumor phenotype are reached. Melatonin has the ability to dynamically affect the epigenetic code. It has become accepted that melatonin can reverse (epi)genetic aberrations present in oral and other cancers, suggesting the possibility of enhancing the oncostatic capacity of standard multimodal treatments by incorporating this indolamine as an adjuvant. First steps in this direction confirm the potential of melatonin as a countermeasure to mitigate the detrimental side effects of conventional first-line radiochemotherapy. This single effect could produce synergies of extraordinary clinical importance, allowing doses to be increased and treatments not to be interrupted, ultimately improving patients' quality of life and prognosis. Motivated by the urgency of improving the medical management of oral cancer, many authors advocate moving from in vitro and preclinical research, where the bulk of melatonin cancer research is concentrated, to systematic randomized clinical trials on large cohorts. Recognizing the challenge to improve the clinical management of cancer, our motivation is to encourage comprehensive and robust research to reveal the clinical potential of melatonin in oral cancer control. To improve the outcome and quality of life of patients with oral cancer, here we provide the latest evidence of the oncolytic activity that melatonin can achieve by manipulating epigenetic patterns in oronasopharyngeal tissue.