Glycyrrhizin prevents 3-nitropropionic acid-induced neurotoxicity by downregulating HMGB1/TLR4/NF-κB p65 signaling, and attenuating oxidative stress, inflammation, and apoptosis in rats

AIMS

Glycyrrhizin (Glyc) is a saponin triterpenoid that has signified its efficacy against Huntington's disease (HD). Nonetheless, its mechanism has not been fully clarified. Accordingly, this study was designed to evaluate the plausible mechanism of action of Glyc against 3-nitropropionic acid (3-NP)-induced HD.

MAIN METHODS

Rats were treated with Glyc (50 mg/kg, i.p.) for 3 weeks and 3-NP (10 mg/kg, i.p.) was administered at the latter 2 weeks alongside to induce HD.

KEY FINDINGS

Animals exposed to 3-NP revealed a reduction in body weight, neurobehavioral abnormalities, and various deleterious effects related to overexpression of HMGB1 such as oxidative stress, apoptosis, and inflammation. Promisingly, Glyc administration provided valuable effects by reversing the decline in body weight with improved neurobehavioral deficits. Ameliorating oxidative stress via restoring GSH, SOD, and Nrf2 alongside with MDA suppression was evident. Furthermore, Glyc switched the HMGB1/TLR4/NF-κB p65 signaling off, reduced IL-6, IL-β, TNF-α, caspase-3, and increased Bcl-2 as well as BDNF. All these beneficial effects were mirrored by a better histopathological picture upon using Glyc that suppressed gliosis by reducing GFAP expression as observed in the immunohistochemistry results.

SIGNIFICANCE

Accordingly, the current study demonstrated a promising neuroprotective effect of Glyc against experimentally induced HD through alleviating deleterious events by diverse mechanisms.

Licochalcone D Ameliorates Oxidative Stress-Induced Senescence via AMPK Activation

Increased oxidative stress is a crucial factor for the progression of cellular senescence and aging. The present study aimed to investigate the effects of licochalcone D (Lico D) on oxidative stress-induced senescence, both in vitro and in vivo, and explore its potential mechanisms. Hydrogen peroxide (200 µM for double time) and D-galactose (D-Gal) (150 mg/kg) were used to induce oxidative stress in human bone marrow-mesenchymal stem cells (hBM-MSCs) and mice, respectively. We performed the SA-β-gal assay and evaluated the senescence markers, activation of AMPK, and autophagy. Lico D potentially reduced oxidative stress-induced senescence by upregulating AMPK-mediated activation of autophagy in hBM-MSCs. D-Gal treatment significantly increased the expression levels of senescence markers, such as p53 and p21, in the heart and hippocampal tissues, while this effect was reversed in the Lico D-treated animals. Furthermore, a significant increase in AMPK activation was observed in both tissues, while the activation of autophagy was only observed in the heart tissue. Interestingly, we found that Lico D significantly reduced the expression levels of the receptors for advanced glycation end products (RAGE) in the hippocampal tissue. Taken together, our findings highlight the antioxidant, anti-senescent, and cardioprotective effects of Lico D and suggest that the activation of AMPK and autophagy ameliorates the oxidative stress-induced senescence.

Three new monocyclic monoterpenoid O-glycosides from the roots of Glycyrrhiza uralensis

Three new monocyclic monoterpenoid containing β-D-apiofuranosyl-(1→2)-O-β-D-glucopyranosyl moieties, together with three other known monocyclic monoterpenoid O-glycosides, were obtained from the roots of Glycyrrhiza uralensis for the first time. Their structures were determined by UV, IR, HRESIMS, and 1D and 2D NMR data.[Formula: see text].

Astaxanthin attenuates d-galactose-induced brain aging in rats by ameliorating oxidative stress, mitochondrial dysfunction, and regulating metabolic markers

Astaxanthin (AX) is a red-colored xanthophyll carotenoid with potent antioxidant, anti-inflammatory, and neuroprotective properties. However, the underlying in vivo mechanism by which AX protects the brain from oxidative stress remains unclear. In this study, we investigated the protective effect of AX on brain oxidative damage in a d-galactose-induced rat model of aging. We also explored its possible mechanism of action by analyzing the resulting serum metabolic profiles. Our results showed that AX significantly increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) by 26%, 30%, and 53%, respectively. AX also significantly increased the mitochondrial membrane potential by 18% when compared with the model group. Additionally, treatment with AX (15 mg kg^-1) increased the activities of respiratory chain complexes I and IV by 50.17% and 122.87%, respectively. Furthermore, AX also improved age-related morphological changes in the cerebral cortex and hippocampus. Significant differences in serum metabolic profiles were observed between the d-galactose and AX treatment groups. AX corrected amino acid metabolic problems by increasing the levels of N-acetyl-l-leucine, N-acetyl-l-tyrosine, and methionine sulfoxide to protect nerve cells. This also allowed AX to regulate the pentose phosphate pathway by acting on ergotoxine, d-xylose-5-phosphoric, and thiamine, to against oxidative stress and apoptosis. Moreover, AX reduced the levels of both hyodeoxycholic acid and chenodeoxycholic acid though the primary bile acid biosynthesis pathway, resulting in improved brain mitochondrial dysfunction. In conclusion, AX likely enhances the brain's antioxidant defenses through these potential metabolic means, enabling the brain to resist mitochondrial dysfunction, improve neuronal damage, and protect the electron transmission of mitochondrial respiratory chain, thus preventing brain aging.

The intervention effect of licorice in d-galactose induced aging rats by regulating the taurine metabolic pathway

A potential protective mechanism of licorice in d-galactose induced aging rats.