Magnesium: does it reduce ischemia/reperfusion injury in an adnexal torsion rat model?

Etomidate alleviates ovarian ischemia-reperfusion injury in rats

BACKGROUND

This study investigates the protective effects of etomidate against oxidative damage in an experimental model of ovarian ischemia-reperfusion injury.

METHODS

A total of 24 female rats were randomized into three groups. Group 1 served as the control. Group 2 underwent an ovarian torsion/detorsion procedure. Group 3 underwent similar procedures as Group 2; additionally, 4 mg/kg of etomidate was administered intraperitoneally 30 minutes before ovarian detorsion. Blood samples were analyzed for lipid peroxidation, pro-inflammatory cytokine levels, and antioxidant enzyme activity RESULTS: Biochemical analysis of blood samples revealed reductions in pro-inflammatory cytokines, including interleukin-1 Beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), in Group 3 compared to Group 2 (p=0.005, p=0.016, and p<0.001, respectively). Additionally, a decrease in malondialdehyde (MDA) levels was observed in Group 3 compared to Group 2 (p<0.001). In contrast, activities of antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), were significantly increased in Group 3 compared to Group 2 (p=0.031 and p=0.001, respectively). Furthermore, Group 3 demonstrated notable reductions in histopathological scores for follicular degeneration, vascular occlusion, bleeding, and inflammation compared to Group 2 (p<0.001, p<0.001, p<0.001, and p=0.001, respectively).

CONCLUSION

Etomidate alleviates ischemia-reperfusion injury in a rat ovarian torsion-detorsion model by improving both histopathological and biochemical outcomes.

Metal profiling in coronary ischemia-reperfusion injury: Implications for KEAP1/NRF2 regulated redox signaling

Coronary ischemia-reperfusion (IR) injury results from a blockage of blood supply to the heart followed by restoration of perfusion, leading to oxidative stress induced pathological processes. Nuclear factor erythroid 2-related factor 2 (NRF2), a master antioxidant transcription factor, plays a key role in regulating redox signaling. Over the past decades, the field of metallomics has provided novel insights into the mechanism of pro-oxidant and antioxidant pathological processes. Both redox-active (e.g. Fe and Cu) and redox-inert (e.g. Zn and Mg) metals play unique roles in establishing redox balance under IR injury. Notably, Zn protects against oxidative stress in coronary IR injury by serving as a cofactor of antioxidant enzymes such as superoxide dismutase [Cu-Zn] (SOD1) and proteins such as metallothionein (MT) and KEAP1/NRF2 mediated antioxidant defenses. An increase in labile Zn2+ inhibits proteasomal degradation and ubiquitination of NRF2 by modifying KEAP1 and glycogen synthase kinase 3β (GSK3β) conformations. Fe and Cu catalyse the formation of reactive oxygen species via the Fenton reaction and also serve as cofactors of antioxidant enzymes and can activate NRF2 antioxidant signaling. We review the evidence that Zn and redox-active metals Fe and Cu affect redox signaling in coronary cells during IR and the mechanisms by which oxidative stress influences cellular metal content. In view of the unique double-edged characteristics of metals, we aim to bridge the role of metals and NRF2 regulated redox signaling to antioxidant defenses in IR injury, with a long-term aim of informing the design and application of novel therapeutics.

Magnesium sulfate ameliorates sepsis-induced diaphragm dysfunction in rats via inhibiting HMGB1/TLR4/NF-κB pathway

Diaphragm dysfunction could be induced by sepsis with subsequent ventilatory pump failure that is associated with local infiltration of inflammatory factors in the diaphragm. It has been shown that the administration of anticonvulsant agent, magnesium sulfate (MgSO₄) could decrease systematic inflammatory response. We recently reported that MgSO₄ could inhibit macrophages high mobility group box 1 (HMGB1) secretion that confirms its anti-inflammatory properties. Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signal pathway appears to be involved in the pathology of septic experimental animal’s inflammatory response and involve in the pathogenic mechanisms of sepsis-induced diaphragm dysfunction. Thus, in this study, we are aiming to explore whether MgSO₄ could ameliorate sepsis-induced diaphragm dysfunction via TLR4/NF-κB pathway in a rodent model with controlled mechanical ventilation (CMV) and subsequent septic challenge.

Effect of magnesium sulfate in oxidized lipid bilayers properties by using molecular dynamics

Magnesium sulfate (MgSO₄) has been used as a protector agent for many diseases related to oxidative stress. The effect of MgSO₄ on the oxidized lipid bilayer has not yet been studied using molecular dynamics calculations. In this work, the effects of oxidation were evaluated by using a POPC membrane model at different concentrations of its aldehyde (-CHO) and hydroperoxide (-OOH) derivatives with and without MgSO₄. Several quantitative and qualitative properties were evaluated, such as membrane thickness, area per lipid, area compressibility modulus, snapshots after simulation finish, density distributions, time evolutions of oxidized group positions, and radial distributions of oxidized group concerning Mg. Results indicate that in the absence of MgSO₄ the mobility of oxidized groups, particularly –CHO, toward the surface interface is high. At a low oxidation level of the bilayer there is an increase in the compressibility modulus as compared to the unoxidized bilayer. MgSO₄, at a low oxidation level, tends to lessen the oxidation effects by lowering the dispersion in the distribution of oxidized species toward the membrane surface and the water region. However, MgSO₄ does not change the trends of decreasing membrane thickness and area compressibility modulus and increasing area per lipid upon oxidation. In this regard, MgSO₄ diminishes the electrostatic long-distance attractive interactions between the oxidized groups and the charged headgroups of the interface, owing to the Mg⁺² and SO₄^-2 screening effects and an electrostatic stabilization of the headgroups, preventing the pore formation, which is well-known to occur in oxidized membranes.

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MgSO₄ in vitro restores oxidized membranes but its molecular mechanism is unclear.

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MD simulations of oxidized lipid bilayers were performed with and without of MgSO₄.

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A restriction in the mobility of oxidized groups is produced by MgSO₄.

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Mg⁺² and SO₄⁼ produce screening effects on the oxidized membranes.

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MgSO₄ produce a diminution of electrostatic long-distance attractive interactions.

Octreotide and lanreotide decrease ovarian ischemia-reperfusion injury in rats by improving oxidative and nitrosative stress

AIM

To investigate the protective effect of octreotide and lanreotide on ovarian damage in experimental ovarian ischemia-reperfusion injury.

METHODS

Fifty-six rats were separated into seven groups; group 1: sham group, group 2: surgical control group with 3-h torsion and detorsion, group 3: 0.02 mg/kg s.c. octreotide 30 min before 3-h torsion, group 4; octreotide just after detorsion for 7 days, group 5: octreotide 30 min before torsion and just after detorsion for 7 days, group 6: single time 20 mg/kg s.c. lanreotide before torsion, group 7: single time lanreotide just after detorsion.

RESULTS

All histopathological scores except congestion were significantly lower in group 1 than other groups. In addition, hemorrhage (group 2 vs 4: P < 0.05), degeneration (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.01 and group 2 vs 6: P < 0.05) and total damage score (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.05, group 2 vs 6: P < 0.05 and group 2 vs 7: P < 0.05) were significantly lower than other groups. Moreover, ovarian tissue total oxidant status and oxidative stress index levels were significantly decreased in groups 5 (both P < 0.05) and 7 (both P < 0.05) when compared to group 2. Furthermore, tissue levels of peroxynitrite were significantly higher in group 2 than groups 1, 3 and 5 (all P < 0.05).

CONCLUSIONS

Octreotide and lanreotide have a protective role against ischemia-reperfusion damage in rat torsion detorsion model by improving histopathological and biochemical findings including tissue levels of total oxidant status, oxidative stress index and peroxynitrite.

Magnesium sulfate prophylaxis attenuates the postpartum effects of preeclampsia by promoting M2 macrophage polarization

Preeclampsia is a complex disorder that is characterized by new onset hypertension and proteinuria at or after 20 weeks of gestation. Preeclampsia is a leading cause of maternal and fetal morbidity and mortality. MgSO₄ is commonly used to treat severe preeclampsia, but its mechanism of action is poorly understood, and investigations into the effects of MgSO₄ during the postpartum period are lacking. In this study, timed-pregnant Sprague-Dawley rats received low-dose lipopolysaccharide (LPS) on gestational day 14 to induce preeclampsia. Maternal and fetal outcomes and the macrophage profile 1 week after delivery were explored. On postpartum day (PD) 7, the maternal systolic blood pressure and urinary protein level were significantly increased, the number of M1 macrophages was increased and the number of M2 macrophages was decreased in the maternal kidney and brain; the median duration of gestation, the number of live fetuses, and the fetal weight/placenta weight ratio were significantly decreased; and the percentage of growth-restricted pups and fetal mortality were significantly increased in preeclampsia rats compared to normal pregnant control rats. Prophylactic MgSO₄ decreased blood pressure at PD7, improved pregnancy outcomes, and promoted the polarization of M2 macrophages in the kidney and of M2 microglia in the brain of preeclampsia rats. These findings confirm that the pathophysiology of preeclampsia involves the dysregulation of the inflammatory response and the activation of M1 macrophages in several target organs during pregnancy. MgSO₄ prophylaxis attenuates the postpartum effects of preeclampsia by promoting M2 macrophage polarization in the maternal kidney and brain.