Protective effects of manganese(II) chloride on hyaluronan degradation by oxidative system ascorbate plus cupric chloride

Development of a Nanohybrid Peptide Hydrogel for Enhanced Intervertebral Disc Repair and Regeneration

Effective therapeutic approaches to overcome the heterogeneous pro-inflammatory and inhibitory extracellular matrix (ECM) microenvironment are urgently needed to achieve robust structural and functional repair of severely wounded fibrocartilaginous tissues. Herein we developed a dynamic and multifunctional nanohybrid peptide hydrogel (NHPH) through hierarchical self-assembly of peptide amphiphile modified with biodegradable two-dimensional nanomaterials with enzyme-like functions. NHPH is not only injectable, biocompatible, and biodegradable but also therapeutic by catalyzing the scavenging of pro-inflammatory reactive oxygen species and promoting ECM remodeling. In addition, our NHPH method facilitated the structural and functional recovery of the intervertebral disc (IVD) after severe injuries by delivering pro-regenerative cytokines in a sustained manner, effectively suppressing immune responses and eventually restoring the regenerative microenvironment of the ECM. In parallel, the NHPH-enhanced nucleus pulposus cell differentiation and pain reduction in a rat nucleotomy model further validated the therapeutic potential of NHPH. Collectively, our advanced nanoscaffold technology will provide an alternative approach for the effective treatment of IVD degeneration as well as other fibrocartilaginous tissue injuries.

The promising performance of manganese gluconate as a liquid redox sulfur recovery agent against oxidative degradation

This work studied the oxidative degradation performance of manganese gluconate as a liquid redox sulfur recovery (LRSR) agent. The degradation of gluconate in an aerated sulfide containing 0.1 M manganese/0.8 M gluconate/pH 13 solution was 11% in 47 h and 20% in 100 h of reaction time. With the total price of chelates being more or less comparable, these were superior to the degradation resistance of EDTA chelate in a solution of 0.1 M iron/0.2 M EDTA/pH 8 which degraded by about 30% in 47 h, and NTA in Fe-NTA (0.1 M metal/0.2 M chelate/pH 6.5), which was degraded by 40% in 100 h of reaction time. At pH of 13, 0.1 M Metal, and 0.8 M gluconate, manganese degraded gluconate more severely than iron and copper. At a lower chelate to metal molar ratio (RCM) of 2 and as well as at a lower pH of 10, the manganese gluconate degradation, expressed as relative concentration to its initial concentration, was faster than at RCM of 8 and pH of 13. All of these observations can be explained among others by the well-known Fenton reaction hydroxyl radicals mechanism as the main cause of the degradation process.

Manganese gluconate, A greener and more degradation resistant agent for H2S oxidation using liquid redox sulfur recovery process

Iron chelate liquid redox sulfur recovery (LRSR) has been one of the most frequently recommended technologies for the oxidation of H₂S in natural gas into elemental sulfur, particularly when the acid gas has a high CO₂/H₂S molar ratio. The process is however known to suffer from extensive oxidative ligand degradation that results in high operational costs. Moreover, poor biodegradability or toxicity of the existing ligand has become a concern. In this research, we demonstrated that gluconate, a naturally greener ligand, when coupled with manganese as the metal, has considerable potential to be a better redox agent. Manganese gluconate solution was more resistant against ligand degradation compared with iron NTA. As required, aerated solution was capable of converting dissolved NaHS into elemental sulfur. At sufficiently high pH, manganese gluconate solutions were stable enough from precipitation of manganese hydroxide, carbonate, or sulfides. An equilibrium calculation has been developed to understand the precipitation behavior.

Citrate functionalized Mn3O4 in nanotherapy of hepatic fibrosis by oral administration

Aim:

To test the potential of orally administered citrate functionalized Mn₃O₄ nanoparticles (C-Mn₃O₄ NPs) as a therapeutic agent against hepatic fibrosis and associated chronic liver diseases.

Materials & methods:

C-Mn₃O₄ NPs were synthesized and the pH dependent antioxidant mechanism was characterized by in vitro studies. CCl₄ intoxicated mice were orally treated with C-Mn₃O₄ NPs to test its in vivo antioxidant and antifibrotic ability.

Results:

We demonstrated ultrahigh efficacy of the C-Mn₃O₄ NPs in treatment of chronic liver diseases such as hepatic fibrosis and cirrhosis in mice compared with conventional medicine silymarin without any toxicological implications.

Conclusion:

These findings may pave the way for practical clinical use of the NPs as safe medication of chronic liver diseases associated with fibrosis and cirrhosis in human subjects.

Hepatic fibrosis is a common response to chronic liver injury from a number of causes including alcohol, toxin, and persistent viral and helminthic infections, which may ultimately lead to hepatic carcinoma. Although billions of people are affected throughout the world, there is no drug available for treatment of this chronic disease. Here, in a preclinical study, we have shown that oral administration of citrate functionalized Mn₃O₄ nanoparticles can effectively reduce the extent of liver fibrosis in mice. We have also predicted the underlying therapeutic mechanism that involves mitochondria and antioxidant systems of the body.

Tsga10 expression correlates with sperm profiles in the adult formalin-exposed mice

Testis-specific gene antigen10 (Tsga10), as a cytoskeletal protein in the sperm tail, impacts the sperm motility. This study investigates the correlation between sperm profile alterations and Tsga10 gene expression in adult mice exposed to formaldehyde (FA) and then treated with antioxidant effect of manganese (Mn²⁺ ). In this regard, we examined 35 NMRI adult male mice (6-8 weeks age) in 4 groups of control, sham, FA-exposed and FA+Mn²⁺ . The mice in FA+Mn²⁺ group were exposed to FA (10 mg kg^-1 twice a day) for 2 weeks and treated with daily Mn²⁺ administration (5 mg kg^-1 ) in the second week prior to sacrificing the mice for testis dissection. The right testis was dissected in each group and subjected to RNA extraction and cDNA syntheses for gene expression analysis by real-time PCR. The findings revealed that FA decreased sperm parameters and Tsga10 expression (52.6 ± 24.37%). However, the injected powerful manganese antioxidant improved sperm profile through overexpression of Tsga10 (121.6 ± 27.13%) under FA-induced stressful condition which proves the correlation between sperm profile and Tsga10 expression (P ≤ 0.05). This study also shows that Tsga10 expression protects sperm dysfunction in FA+Mn²⁺ group and resulting in better preservation of spermatozoa and improvement of male fertility.

Oxidation of glycosaminoglycans by free radicals and reactive oxidative species: A review of investigative methods

Glycosaminoglycans, in particular hyaluronan (HA), and proteoglycans are components of the extracellular matrix (ECM). The ECM plays a key role in the regulation of cellular behaviour and alterations to it can modulate both the development of human diseases as well as controlling normal biochemical processes such as cell signalling and pro-inflammatory responses. For these reasons, in vitro fragmentation studies of glycosaminoglycans by free radicals and oxidative species are seen to be relevant to the understanding of in vivo studies of damage to the ECM. A wide range of investigative techniques have therefore been applied to gain insights into the relative fragmentation effects of several reactive oxidative species with the ultimate goal of determining mechanisms of fragmentation at the molecular level. These methods are reviewed here.

Protective effect of manganese in cadmium-induced hepatic oxidative damage, changes in cadmium distribution and trace elements level in mice

Oxidative tissue damage is considered an early sign of cadmium (Cd) toxicity and has been linked with carcinogenesis. Manganese(II)-at low doses, was found to act as a potent antioxidant against oxidative stress in different in vitro systems producing lipid peroxidation conditions. The present study investigates in vivo antioxidant effects of Mn²⁺ pretreatment in acute Cd intoxication with regard to lipid peroxidation, antioxidant defense system and cadmium distribution in the tissues of mice. Four groups of male mice (n=7–8) were used: Cd group was injected sc a single dose of CdCl₂ · 2½ H₂O · (7 mg/kg b.w.); Cd+Mn group was treated ip with MnCl₂ · 4H₂O (20 mg/kg b.w.) 24 hours before Cd intoxication; Mn group received manganese treatment only; Control group received saline only. Twenty-four hours after Cd intoxication an increased lipid peroxidation (p<0.05), depleted GSH level (p<0.01), increased activity of GSH-Px (p<0.05) and inhibited CAT activity (p<0.01) were found in Cd-treated group compared to controls. Manganese(II) pre-treatment either completely prevented (LP, GSH, GSH-Px) or significantly attenuated (CAT) these changes. Manganese(II) treatment alone decreased LP, enhanced hepatic GSH level and had no effect on antioxidant enzymes compared to control group. A significant increase of Cd concentration in the liver and decreased Cd concentration in the kidneys and testes were found in Cd+Mn treated mice compared to Cd-only treated group. The effect of manganese may result from a different metallothionein induction in particular organs. Manganese(II) pretreatment attenuated the interference of cadmium with Ca homeostasis, the alteration in Zn and Cu levels remained mostly unaffected.