The effects of a free radical scavenger, edaravone, combined with mild hypothermia on ischemic brain damage following transient middle cerebral artery occlusion in rats

A Systematic Review and Meta-Analysis of Therapeutic Hypothermia and Pharmacological Cotherapies in Animal Models of Ischemic Stroke

Therapeutic hypothermia (TH) lessens ischemic brain injury. Cytoprotective agents can augment protection, although it is unclear which combinations are most effective. The objective of this study is to identify which cytoprotective drug works best with delayed TH. Following PRISMA guidelines, a systematic review (PubMed, Web of Science, MEDLINE, Scopus) identified controlled experiments that used an in vivo focal ischemic stroke model and evaluated the efficacy of TH (delay of ≥1 hour) coupled with cytoprotective agents. This combination was our main intervention compared with single treatments with TH, drug, or no treatment. Endpoints were brain injury and neurological impairment. The CAMARADES checklist for study quality and the SYRCLE's risk of bias tool gauged study quality. Twenty-five studies were included. Most used young, healthy male rats, with only one using spontaneously hypertensive rats. Two studies used mice models, and six used adult animals. Study quality was moderate (median score = 6), and risk of bias was high. Pharmacological agents provided an additive effect on TH for all outcomes measured. Magnesium coupled with TH had the greatest impact compared with other agent-TH combinations on all outcomes. Longer TH durations improved both behavioral and histological outcomes and had greater cytoprotective efficacy than shorter durations. Anti-inflammatories were the most effective in reducing infarction (standardized mean difference [SMD]: -1.64, confidence interval [CI]: [-2.13, -1.15]), sulfonylureas reduced edema the most (SMD: -2.32, CI: [-3.09, -1.54]), and antiapoptotic agents improved behavioral outcomes the most (normalized mean difference: 52.38, CI: [45.29, 59.46]). Statistically significant heterogeneity was observed (I2 = 82 - 98%, all p < 0.001), indicating that studies wildly differ in their effect size estimates. Our results support the superiority of adding cytoprotective therapies with TH (vs. individual or no therapy). Additional exploratory and confirmatory studies are required to identify and thoroughly assess combination therapies owing to limited work and inconsistent translational quality.

The Use of Hemoglobin Vesicles for Delivering Medicinal Gas for the Treatment of Intractable Disorders

Bioactive gaseous molecules, such as oxygen (O₂) and carbon monoxide (CO), are essential elements for most living organisms to maintain their homeostasis and biological activities. An accumulating body of evidence suggests that such molecules can be used in clinics as a medical gas in the treatment of various intractable disorders. Recent developments in hemoglobin-encapsulated liposomes, namely hemoglobin vesicles (HbV), possess great potential for retaining O₂ and CO and could lead to strategies for the development of novel pharmacological agents as medical gas donors. HbV with either O₂ or CO bound to it has been demonstrated to have therapeutic potential for treating certain intractable disorders and has the possibility to serve as diagnostic and augmenting product by virtue of unique physicochemical characteristics of HbV. The present review provides an overview of the present status of the use of O₂- or CO-binding HbV in experimental animal models of intractable disorders and discusses prospective clinical applications of HbV as a medical gas donor.

Protective Effect of Edaravone Against Cyclosporine-Induced Chronic Nephropathy Through Antioxidant and Nitric Oxide Modulating Pathways in Rats

BACKGROUND

Cyclosporine A (CsA) is an immunosuppressant with therapeutic indications in various immunological diseases; however, its use is associated with chronic nephropathy. Oxidative stress has a crucial role in CsA-induced nephrotoxicity. The present study evaluates the protective effect of edaravone on CsA-induced chronic nephropathy and investigates its antioxidant and nitric oxide modulating property.

METHODS

Male Sprague-Dawley rats (n=66) were distributed into nine groups, including a control (group 1) (n=7). Eight groups received CsA (15 mg/kg) for 28 days while being treated. The groups were categorized as: Group 2: Vehicle (n=10)Groups 3, 4, and 5: Edaravone (1, 5, and 10 mg/kg) (n=7 each)Group 6: Diphenyliodonium chloride, a specific endothelial nitric oxide synthase (eNOS) inhibitor (n=7)Group 7: Aminoguanidine, a specific inducible nitric oxide synthase (iNOS) inhibitor (n=7)Group 8: Edaravone (10 mg/kg) plus diphenyliodonium chloride (n=7)Group 9: Edaravone (10 mg/kg) plus aminoguanidine (n=7) Blood urea nitrogen and serum creatinine levels, malondialdehyde, superoxide dismutase, and glutathione reductase enzyme activities were measured using standard kits. Renal histopathological evaluations and measurements of eNOS and iNOS gene expressions by RT-PCR were also performed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's test (SPSS software version 18.0).

RESULTS

Edaravone (10 mg/kg) significantly attenuated CsA-induced oxidative stress, renal dysfunction, and kidney tissue injury. Aminoguanidine improved the renoprotective effect of edaravone. Edaravone reduced the elevated mRNA level of iNOS, but could not alter the level of eNOS mRNA significantly.

CONCLUSION

Edaravone protects against CsA-induced chronic nephropathy using antioxidant property and probably through inhibiting iNOS gene expression.

Effect of hemoglobin vesicle, a cellular-type artificial oxygen carrier, on middle cerebral artery occlusion- and arachidonic acid-induced stroke models in rats

Hemoglobin vesicle (HbV), which is also called liposome-encapsulated hemoglobin, functions as a hemoglobin-based oxygen carrier and is expected to be utilized in emergency situations including hemorrhagic shock and several kinds of ischemic diseases. In the present study, we evaluated the efficacy of HbV for improving stroke-related symptoms induced by middle cerebral artery (MCA) occlusion/reperfusion and an intra-internal carotid arterial injection of arachidonic acid (AA) in rats. When HbV (10 mL/kg, i.v.) was administered to rats immediately after the MCA occlusion, it reduced the cerebral infarct volumes of the cortex and total of the cortex plus sub-cortex significantly as compared with saline as a vehicle. In AA-induced stroke model, HbV (10 mL/kg, i.v.) improved the motor dysfunction score and inhibited the increase in cerebral water content suggesting it could suppress cerebral edema. These results strongly suggest that HbV would provide a novel beneficial option for the treatment of stroke, especially acute ischemic stroke.