Protective effects of dietary curcumin and astaxanthin against heat-induced ROS production and skeletal muscle injury in male and female C57BL/6J mice

Effects of an astaxanthin-containing supplement on oxidative status in skeletal muscle and circulation during deconditioning and reconditioning periods in polo ponies

This study investigated the effects of astaxanthin (ASTX) supplementation on oxidative status during a deconditioning-reconditioning cycle. Twelve polo ponies were assigned to no supplementation (CON) or an ASTX supplemented group, which received oral administration of a supplement containing 75 mg ASTX daily for 32 weeks. Polo ponies underwent a 16-week deconditioning period (DECON) followed by a 16-week reconditioning program (RECON). Submaximal exercise tests (SETs) were performed at the beginning of the study (Baseline), after DECON, and after RECON. Blood samples were collected at -30, 0, 15, 30, and 60 min relative to each SET for oxidative status analysis. Muscle samples were collected 2 weeks before (Pre-Ex) and 2 h after (Post-Ex) each SET for muscle oxidative status and gene expression analyses. Pre-Ex muscles were analyzed for high-resolution respirometry. Circulating glutathione peroxidase (GPX) activity was increased (p ≤ 0.02) and protein carbonylation was decreased in ASTX (p ≤ 0.05). Muscle oxidative status was affected by DECON and reconditioning (p ≤ 0.05). ASTX increased gene expression of PPARGC1A after reconditioning (p ≤ 0.05). Deconditioning reduced oxidative phosphorylation at complex I and II (p = 0.01). Thus, a deconditioning-reconditioning cycle had greater impacts on muscle oxidative capacity than ASTX supplementation.

Astaxanthin Alleviates Oxidative Stress in Mouse Preantral Follicles and Enhances Follicular Development Through the AMPK Signaling Pathway

This study investigates the effects of astaxanthin on oxidative stress, mitochondrial function, and follicular development in mouse preantral follicles, with a focus on the involvement of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Astaxanthin (2.5 nM) significantly enhanced both the antrum formation (from 85.96% in the control group to 94.38% in the astaxanthin group) and maturation rates (from 79.15% to 85.12%) of oocytes (p < 0.05). From day 4 of in vitro culture, astaxanthin notably increased the area of follicle attachment (from 0.06 µm2 to 0.32 µm2) and the secretion of estradiol (from 32.10 ng/L to 49.73 ng/L) (p < 0.05). Additionally, it significantly decreased malondialdehyde content (from 80.54 μM to 62.65 μM) within the follicles while increasing the mRNA expression levels of glutathione and superoxide dismutase 1 (p < 0.05). Astaxanthin also reduced reactive oxygen species levels in oocytes (p < 0.05). Notably, astaxanthin enhanced the expression of p-AMPK and PGC-1α, which are key proteins for the AMPK pathway; NRF1 and TFAM, which are crucial for mitochondrial biogenesis; NRF2 and HO-1, which protect against oxidative stress; CO1, CO2, CO3, ATP6, ATP8, and TOM20, which are essential for electron transport chain activity and ATP synthesis; PINK1, Parkin, and LC3-II, which are involved in mitophagy; Bcl-2, which inhibits cell apoptosis; and StAR and P450scc, which promote estrogen synthesis (p < 0.05). Furthermore, astaxanthin improved mitochondrial membrane potential and decreased the expression of cleaved caspase 3, Bax, and P53, which promotes cell apoptosis (p < 0.05). However, these changes induced by astaxanthin were completely reversed by AMPK inhibitors, indicating the involvement of the AMPK pathway. Conclusively, astaxanthin enhances the in vitro development of follicles, alleviates oxidative stress in preantral follicles, and promotes mitochondrial function during in vitro culture, which may be mediated by the AMPK pathway.

Acute heat stress upregulates Akr1b3 through Nrf-2 to increase endogenous fructose leading to kidney injury

In recent years, the prevalence of extremely high-temperature climates has led to an increase in cases of acute heat stress (HS), which has been identified as a contributing factor to various kidney diseases. Fructose, the end product of the polyol pathway, has been linked to kidney conditions such as kidney stones, chronic kidney disease, and acute kidney injury. However, the relationship between acute HS and kidney injury caused by endogenous fructose remains unclear. The study found that acute HS triggers the production of reactive oxygen species, which in turn activate the Nrf-2 and Akr1b3 leading to an increase in endogenous fructose levels in kidney cells. It was further demonstrated that the elevated levels of endogenous fructose play a crucial role in causing damage to kidney cells. Moreover, inhibiting Nrf-2 effectively mitigated kidney damage induced by acute HS by reducing endogenous fructose levels. These findings underscore the detrimental impact of excessive fructose resulting from acute stress on kidney function, offering a novel perspective for future research on the prevention and treatment of acute HS-induced kidney injury.

Astaxanthin mitigates doxorubicin-induced cardiotoxicity via inhibiting ferroptosis and autophagy: a study based on bioinformatic analysis and in vivo/vitro experiments

Background

Doxorubicin (DOX), a widely employed chemotherapeutic agent in cancer treatment, has seen restricted use in recent years owing to its associated cardiotoxicity. Current reports indicate that doxorubicin-induced cardiotoxicity (DIC) is a complex phenomenon involving various modes of cell death. Astaxanthin (ASX), a natural carotenoid pigment, has garnered significant attention for its numerous health benefits. Recent studies have shown that ASX has a broad and effective cardiovascular protective effect. Our study aims to investigate the protective effects of ASX against DIC and elucidate its underlying mechanisms. This has substantial practical significance for the clinical application of DOX.

Methods

Bioinformatic analyses were conducted using transcriptomic data from the gene expression omnibus (GEO) database to identify key mechanisms underlying DIC. Network pharmacology was employed to predict the potential pathways and targets through which ASX exerts its effects on DIC. In vitro experiments, following pretreatment with ASX, H9C2 cells were exposed to DOX. Cell viability, injury and the protein expression levels associated with ferroptosis and autophagy were assessed. In the animal experiments, rats underwent 4 weeks of gavage treatment with various doses of ASX, followed by intraperitoneal injections of DOX every 2 days during the final week. Histological, serum, and protein analyses were conducted to evaluate the effects of ASX on DIC.

Results

The bioinformatics analysis revealed that ferroptosis and autophagy are closely associated with the development of DIC. ASX may exert an anti-DIC effect by modulating ferroptosis and autophagy. The experimental results show that ASX significantly mitigates DOX-induced myocardial tissue damage, inflammatory response, oxidative stress, and damage to H9C2 cells. Mechanistically, ASX markedly ameliorates levels of ferroptosis and autophagy both in vitro and in vivo. Specifically, ASX upregulates solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), while downregulating the expression of transferrin receptor 1 (TFRC), ferritin heavy chain (FTH1) and ferritin light chain (FTL). Additionally, ASX enhances the expression of P62 and decreases levels of Beclin1 and microtubule-associated proteins light chain 3 (LC3).

Conclusion

Our results indicate that ferroptosis and autophagy are critical factors influencing the occurrence and progression of DOX-induced cardiotoxicity. ASX can alleviate DIC by inhibiting ferroptosis and autophagy.

Maintaining mitochondrial NAD+ homeostasis is key for heat-induced skeletal muscle injury prevention despite presence of intracellular cation alterations

Mitochondrial dysfunction is implicated in heat-induced skeletal muscle (SKM) injury and its underlying mechanisms remain unclear. Evidence suggests that cellular ions and molecules, including divalent cations and adenine nucleotides, are involved in the regulation of mitochondrial function. In this study, we examined Ca2+, Mg2+, and NAD+ levels in mouse C2C12 myoblasts and SKM in response to heat exposure. During heat exposure, mitochondrial Ca2+ levels increased significantly, whereas cytosolic Ca2+ levels remained unaltered. The mitochondrial Ca2+ levels in the SKM of heat-exposed mice were 28% higher compared to control mice. No changes in cytosolic Ca2+ were detected between the two groups. Following heat exposure, cytosolic and mitochondrial Mg2+ levels were reduced by 47% and 23% in C2C12 myoblasts, and by 51% and 44% in mouse SKMs, respectively. In addition, heat exposure decreased mitochondrial NAD+ levels by 32% and 26% in C2C12 myoblasts and mouse SKMs, respectively. Treatment with the NAD+ precursor nicotinamide riboside (NR) partially prevented heat-induced depletion of NAD+. Additionally, NR significantly reduced heat-increased mitochondrial fission, mitochondrial depolarization, and apoptosis in C2C12 myoblasts and mouse SKMs. No effects of NR on heat-induced changes in intracellular Ca2+ and Mg2+ levels were observed. This study provides in vitro and in vivo evidence that acute heat stress causes alterations in mitochondrial Ca2+, Mg2+, and NAD+ homeostasis. Our results suggest mitochondrial NAD+ homeostasis as a therapeutic target for the prevention of heat-induced SKM injury.

Curcumin regulates autophagy through SIRT3-SOD2-ROS signaling pathway to improve quadriceps femoris muscle atrophy in KOA rat model

Knee osteoarthritis (KOA) usually leads to quadriceps femoris atrophy, which in turn can further aggravate the progression of KOA. Curcumin (CUR) has anti-inflammatory and antioxidant effects and has been shown to be a protective agent for skeletal muscle. CUR has been shown to have a protective effect on skeletal muscle. However, there are no studies related to whether CUR improves KOA-induced quadriceps femoris muscle atrophy. We established a model of KOA in rats. Rats in the experimental group were fed CUR for 5 weeks. Changes in autophagy levels, reactive oxygen species (ROS) levels, and changes in the expression of the Sirutin3 (SIRT3)-superoxide dismutase 2 (SOD2) pathway were detected in the quadriceps femoris muscle of rats. KOA led to quadriceps femoris muscle atrophy, in which autophagy was induced and ROS levels were increased. CUR increased SIRT3 expression, decreased SOD2 acetylation and ROS levels, inhibited the over-activation of autophagy, thereby alleviating quadriceps femoris muscle atrophy and improving KOA. CUR has a protective effect against quadriceps femoris muscle atrophy, and KOA is alleviated after improvement of quadriceps femoris muscle atrophy, with the possible mechanism being the reduction of ROS-induced autophagy via the SIRT3-SOD2 pathway.

Effect of hypobaric hypoxia on the fiber type transition of skeletal muscle: a synergistic therapy of exercise preconditioning with a nanocurcumin formulation

Hypobaric hypoxia (HH) leads to various adverse effects on skeletal muscles, including atrophy and reduced oxidative work capacity. However, the effects of HH on muscle fatigue resistance and myofiber remodeling are largely unexplored. Therefore, the present study aimed to explore the impact of HH on slow-oxidative fibers and to evaluate the ameliorative potential of exercise preconditioning and nanocurcumin formulation on muscle anti-fatigue ability. C2C12 cells (murine myoblasts) were used to assess the effect of hypoxia (0.5%, 24 h) with and without the nanocurcumin formulation (NCF) on myofiber phenotypic conversion. To further validate this hypothesis, male Sprague Dawley rats were exposed to a simulated HH (7620 m) for 7 days, along with NCF administration and/or exercise training. Both in vitro and in vivo studies revealed a significant reduction in slow-oxidative fibers (p < 0.01, 61% vs. normoxia control) under hypoxia. There was also a marked decrease in exhaustion time (p < 0.01, 65% vs. normoxia) in hypoxia control rats, indicating a reduced work capacity. Exercise preconditioning along with NCF supplementation significantly increased the slow-oxidative fiber proportion and exhaustion time while maintaining mitochondrial homeostasis. These findings suggest that HH leads to an increased transition of slow-oxidative fibers to fast glycolytic fibers and increased muscular fatigue. Administration of NCF in combination with exercise preconditioning restored this myofiber remodeling and improved muscle anti-fatigue ability.

Hyaluronic acid-functionalized redox-responsive organosilica nanoparticles for targeted resveratrol delivery to attenuate acrylamide-induced toxicity

The purpose of this study is to construct a redox-responsive and targeted nanoparticle to effectively deliver resveratrol (Res) for alleviating acrylamide (ACR) toxicity. Here, Res-loaded tetrasulfide-containing organosilica nanoparticles (DSMSNs) functionalized with hyaluronic acid on the surface (DSMSNs@Res@HA) were prepared. The DSMSNs@Res@HA nanoparticles were spherical with an encapsulation efficiency of 46.68 ± 1.64 % and a hydrated particle size of about 237.73 nm. As expected, DSMSNs@Res@HA were capable of significantly protecting PC12 cells against ACR-induced damage in oxidative stress, mitochondrial membrane potential decrease, and cell apoptosis compared with free Res and DSMSNs@Res at the equivalent dose. Moreover, DSMSNs@Res@HA could be biodegraded and released Res in response to GSH stimulus. In vivo experiments suggested that DSMSNs@Res@HA significantly reduced histological damage in the brain, liver, and kidney of rats compared with free Res and DSMSNs@Res. After oral administration of DSMSNs@Res@HA, the intestinal flora of ACR-treated rats could be effectively regulated by improving the species uniformity and abundance as well as recovering the species diversity. According to these findings, DSMSNs@Res@HA is worth further investigation as a potential therapeutic nanomedicine to alleviate ACR toxicity and restore gut microbiota diversity.