The neuroprotective mechanisms of naringenin: Inhibition of apoptosis through the PI3K/AKT pathway after hypoxic-ischemic brain damage

Protective effects of dietary additive quercetin: Nephrotoxicity and ferroptosis induced by avermectin pesticide

In recent years, contamination of aquatic systems with Avermectin (AVM) has emerged as a significant concern. This contamination poses substantial challenges to freshwater aquaculture. Plant-derived Quercetin (QUE), known for its anti-inflammatory, antioxidant, and ferroptosis-inhibiting properties, is commonly employed as a supplement in animal feed. However, its protective role against chronic renal injury in freshwater carp induced by AVM remains unclear. This study assesses the influence of dietary supplementation with QUE on the consequences of chronic AVM exposure on carp renal function. The carp were subjected to a 30-day exposure to AVM and were provided with a diet containing 400 mg/kg of QUE. Pathological observations indicated that QUE alleviated renal tissue structural damage caused by AVM. RT-QPCR study revealed that QUE effectively reduced the increased expression levels of pro-inflammatory factors mRNA produced by AVM exposure, by concurrently raising the mRNA expression level of the anti-inflammatory factor. Quantitative analysis using DHE tests and biochemical analysis demonstrated that QUE effectively reduced the buildup of ROS in the renal tissues of carp, activity of antioxidant enzymes CAT, SOD, and GSH-px, which were inhibited by AVM, and increased the content of GSH, which was induced by prolonged exposure to AVM. QUE also reduced the levels of MDA, a marker of oxidative damage. Furthermore, assays for ferroptosis markers indicated that QUE increased the mRNA expression levels of gpx4 and slc7a11, which were reduced due to AVM induction, and it caused a reduction in the mRNA expression levels of ftl, ncoa4, and cox2, along with a drop in the Fe2+ concentration. In summary, QUE mitigates chronic AVM exposure-induced renal inflammation in carp by inhibiting the transcription of pro-inflammatory cytokines. By blocking ROS accumulation, renal redox homeostasis is restored, thereby inhibiting renal inflammation and ferroptosis. This provides a theoretical basis for the development of freshwater carp feed formula.

Puerarin enhances TFEB-mediated autophagy and attenuates ROS-induced pyroptosis after ischemic injury of random-pattern skin flaps

BACKGROUND AND AIM

Necrosis of random-pattern flaps restricts their application in clinical practice. Puerarin has come into focus due to its promising therapeutic effects in ischemic diseases. Here, we employed Puerarin and investigated its role and potential mechanisms in flap survival.

EXPERIMENTAL PROCEDURE

The effect of Puerarin on the viability of human umbilical vein endothelial cells (HUVECs) was assessed by CCK-8, EdU staining, migration, and scratch assays. Survival area measurement and laser Doppler blood flow (LDBF) were utilized to assess the viability of ischemic injury flaps. Levels of molecules related to oxidative stress, pyroptosis, autophagy, transcription factor EB (TFEB), and the AMPK-TRPML1-Calcineurin signaling pathway were detected using western blotting, immunofluorescence, dihydroethidium (DHE) staining, RT-qPCR and Elisa.

KEY RESULTS

The findings demonstrated that Puerarin enhanced the survivability of ischemic flaps. Autophagy, oxidative stress, and pyroptosis were implicated in the ability of Puerarin in improving flap survival. Increased autophagic flux and augmented tolerance to oxidative stress contribute to Puerarin's suppression of pyroptosis. Additionally, Puerarin modulated the activity of TFEB through the AMPK-TRPML1-Calcineurin signaling pathway, thereby enhancing autophagic flux.

CONCLUSIONS AND IMPLICATIONS

Puerarin promoted flap survival from ischemic injury through upregulation of TFEB-mediated autophagy and inhibition of oxidative stress. Our findings offered valuable support for the clinical application of Puerarin in the treatment of ischemic diseases, including random-pattern flaps.

Ginsenoside RK3 promotes neurogenesis in Alzheimer's disease through activation of the CREB/BDNF pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the ancient book "Shen Nong's Herbal Classic," Panax ginseng CA Mey was believed to have multiple benefits, including calming nerves, improving cognitive function, and promoting longevity. Ginsenosides are the main active ingredients of ginseng. Ginsenoside RK3 (RK3), a rare ginsenoside extracted from ginseng, displays strong pharmacological potential. However, its effect on neurogenesis remains insufficiently investigated.

AIM OF THE STUDY

This study aims to investigate whether RK3 improves learning and memory by promoting neurogenesis, and to explore the mechanism of RK3 action.

MATERIALS AND METHODS

The therapeutic effect of RK3 on learning and memory was determined by the Morris water maze (MWM) and novel object recognition test (NORT). The pathogenesis and protective effect of RK3 on primary neurons and animal models were detected by immunofluorescence and western blotting. Protein expression of cAMP response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling pathway was detected by western blotting.

RESULTS

Our results showed that RK3 treatment significantly improved cognitive function in APPswe/PSEN1dE9 (APP/PS1) mice and C57BL/6 (C57) mice. RK3 promotes neurogenesis and synaptogenesis in the mouse hippocampus. In vitro, RK3 prevents Aβ-induced injury in primary cultured neurons and promotes the proliferation of PC12 as well as the expression of synapse-associated proteins. Mechanically, the positve role of RK3 on neurogenesis was combined with the activation of CREB/BDNF pathway. Inhibition of CREB/BDNF pathway attenuated the effect of RK3.

CONCLUSION

In conclusion, this study demonstrated that RK3 promotes learning and cognition in APP/PS1 and C57 mice by promoting neurogenesis and synaptogenesis through the CREB/BDNF signaling pathway. Therefore, RK3 is expected to be further developed into a potential drug candidate for the treatment of Alzheimer's disease (AD).

MicroRNA-124 negatively regulates STAT3 to alleviate hypoxic-ischemic brain damage by inhibiting oxidative stress

MicroRNA-124 (miR-124) is implicated in various neurological diseases; however, its significance in hypoxic-ischaemic brain damage (HIBD) remains unclear. This study aimed to elucidate the underlying pathophysiological mechanisms of miR-124 in HIBD. In our study performed on oxygen-glucose deprivation followed by reperfusion (OGD)/R-induced primary cortical neurons, a substantial reduction in miR-124 was observed. Furthermore, the upregulation of miR-124 significantly mitigated oxidative stress, apoptosis, and mitochondrial impairment. We demonstrated that miR-124 interacts with the signal transducer and activator of transcription 3 (STAT3) to exert its biological function using the dual-luciferase reporter gene assay. As the duration of OGD increased, miR-124 exhibited a negative correlation with STAT3. STAT3 overexpression notably attenuated the protective effects of miR-124 mimics, while knockdown of STAT3 reversed the adverse effects of the miR-124 inhibitor. Subsequently, we conducted an HIBD model in rats. In vivo experiments, miR-124 overexpression attenuated cerebral infarction volume, cerebral edema, apoptosis, oxidative stress, and improved neurological function recovery in HIBD rats. In summary, the neuroprotective effects of the miR-124/STAT3 axis were confirmed in the HIBD model. MiR-124 may serve as a potential biomarker with significant therapeutic implications for HIBD.

Neuroprotective mechanism of salvianolic acid B against cerebral ischemia-reperfusion injury in mice through downregulation of TLR4, p-p38MAPK, p-JNK, NF-κB, and IL-1β

OBJECTIVE

Tissue injury and inflammation are two potential outcomes of cerebral ischemia-reperfusion (I/R) injury. Salvianolic acid B (Sal B), isolated from the roots of Salvia miltiorrhiza, is one of the major water-soluble compounds with a wide range of pharmacological effects including antioxidant, anti-inflammatory, antiproliferative, and neuroprotective effects. In the present study, we explored the neuroprotective effects and potential mechanisms of Sal B after I/R injury.

METHODS

We induced cerebral ischemia in male CD-1 mice through transient (60 min) middle cerebral artery occlusion (tMCAO), and then injected Sal B (30 mg/kg) intraperitoneally. Neurological deficits, infarct volumes, and brain edema were assessed at 24 and 72 h after tMCAO. We detected the expression of Toll-like receptor 4 (TLR4), phosphorylated-p38 mitogen-activated protein kinase (P-p38 MAPK), phosphorylated c-Jun amino (N)-terminal kinases (p-JNK), nuclear factor-κB (NF-κB), and interleukin-1β (IL-1β) in the brain tissue.

RESULTS

Compared with the tMCAO group, Sal B significantly improved neurological deficits, reduced infarct size, attenuated cerebral edema, and downregulated the expression of pro-inflammatory mediators TLR4, p-p38MAPK, p-JNK, nuclear NF-κB, and IL-1β in brain tissue after I/R injury.

CONCLUSION

We found that Sal B protects brain tissues from I/R injury by activating its anti-inflammatory properties.