Dendrobine rescues cognitive dysfunction in diabetic encephalopathy by inhibiting ferroptosis via activating Nrf2/GPX4 axis.

BACKGROUND: Ferroptosis playsa crucial role in the development of dementia and dendrobine (Den)possesseshypoglycemic and neuroprotective effects. However, the character of ferroptosis in diabetic encephalopathy (DE) and Den's therapeutic effect remains unclear. PURPOSE: This study aimed to verify the effects of Den on ferroptosis in treating DE and underlying mechanisms. STUDY DESIGN: Den's therapeutic effect was assessed in db/db mice and advanced glycation end products (AGEs)-induced HT22 cells. METHODS: After oral administration with Den orMetformin for 8-week, behavioral tests were used to assess cognitive capacity. Then, biochemical analysis was preformed to detect glucose and lipid metabolism levels; histological analysis and transmission electron microscope were applied to evaluate pathological injuries. Meanwhile, EdU staining and flow cytometry were applied to test cell apoptosis. Furthermore, mitochondrial dynamics, iron transport, and Nrf2/GPX4 axis related proteins were detected by western blot or immunofluorescence. RESULTS: Our results demonstrated that Den remarkably alleviated glucose and lipid metabolism disorders, as well as ameliorated mnemonic deficits of db/db mice. Meanwhile, Den could protect AGEs-induced HT22 cells from death and apoptosis. In addition, we noted that Den inhibited lipid peroxidation by restoring mitochondrial function and reducing reactive oxygen species production. Furthermore, ferroptosis was proven to exist in db/db mice brain and Den could inhibit it via activating Nrf2/GPX4 axis. CONCLUSION: These findings indicated that Den could rescue cognitive dysfunction in DE by inhibiting ferroptosis via activating Nrf2/GPX4 axis.

Protective effect and possible mechanisms of ligustrazine isolated from Ligusticum wallichii on nephropathy in rats with diabetes: A preclinical systematic review and meta-analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Ligusticum wallichii has been used to treat renal diseases for thousands of years in China. Ligustrazine (Lig) is the active ingredient of Ligusticum wallichii that possesses a variety of biological activities against kidney disease. AIM OF THE STUDY: The purpose of this review is to further evaluate whether the supplementation with Lig has an effect on improving renal pathology, renal function indexes and blood glucose levels in animal model of diabetic nephropathy (DN). Potential mechanisms of Lig for DN as well as the existing problems regarding the modeling method and limitations in this area of research were also summarized. MATERIALS AND METHODS: The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) checklist was used to organize the search of eight databases from inception to June 2019. We used Cochrane Collaboration's 10-item checklist and Rev-Man 5.3 software to analyze the data as well as risk of bias. RESULTS: The study quality scores ranged from 2 to 6 points with an average of 4.471. Compared with the control group, Lig significantly improved pathological changes of kidney including glomeruli and tubules, and induced significant decreases in levels of blood urea nitrogen, serum creatinine, 24-h urinary albumin and HbA1c, as well as increasing creatinine clearance rates. In subgroup analysis, the groups of high-dose STZ (≥60 mg/kg) and longer period of Lig treatment (>8 w) showed better results than those of the control group. No difference was seen between the high (>150 mg/kg, QD) and low (≤150 mg/kg, QD) dose of Lig treatment groups. CONCLUSION: Lig exerts renoprotective functions in an animal model of DN mediated by antioxidant action, inhibition of apoptosis, anti-inflammatory action, reduction of renal fibrosis, reduction of the proliferation of mesangial cells, inhibition of endotheliosis, inhibition of atherosclerosis and promotion of renal autophagy. The positive conclusion should be treated cautiously because of various methodological flaws. Further studies are recommended according to ARRIVE guidelines. The method of modeling with high-dose STZ should be avoided and improved STZ modeling schemes are recommended. Considering the large dosage range of Lig used clinically and in animals, the future studies on the basis of animal renal histology are urgently needed to determine the optimal dosages to delay histological changes. Nevertheless, together, our findings suggest that Lig is a renoprotective candidate drug for treatment of DN.

Monoterpene pyridine alkaloids and phenolics from Scrophularia ningpoensis and their cardioprotective effect.

Scrophularianines A-C (1-3), three new unusual monoterpene pyridine alkaloids with cyclopenta [c] pyridine skeleton reported from the genus Scrophularia for the first time, together with 15 known compounds (4-18), were isolated from the extract of Scrophularia ningpoensis. Their structures were elucidated on the basis of extensive analyses of spectroscopic evidences. The biogenetic relationship between monoterpene pyridine alkaloids and iridoids was proposed preliminarily. The myocardial protective bioassay indicated that compounds 13 and 14 with a concentration of 10(-4)M exhibited significantly protective effect against H2O2-induced apoptosis in cardiomyocytes.

[Profiles of reproduction-related mRNA expressions in hypothalamus of female mice with advancing age].

OBJECTIVE: To explore the effects of aging on the levels of reproduction-related mRNA genes including Gnrh, KISS1/KISS1r, estrogen receptor-alpha (ERα), estrogen receptor-beta (ERß) and progesterone receptor (PR) in hypothalamus. METHODS: Proestrus and metestrus in young (3-4 months) and middle-aged (10-11 months) female mice and diestrus in senile (18-19 months) female mice were observed. And the levels of related mRNA genes in preoptic area anterior hypothalamus (POA-AH) and medial basal hypothalamus (MBH) were determined by real-time polymerase chain reaction (RT-PCR). RESULTS: In middle-aged mice on proestrus, the level of Gnrh mRNA in POA-AH (0.896 ± 0.049) was significantly lower than that in young mice (1.228 ± 0.147, P = 0.049). The level of ERα mRNA in POA-AH decreased in young mice on proestrus whereas increased in middle-aged mice (0.432 ± 0.063 vs 0.603 ± 0.018, P = 0.016). The level of ERα mRNA of POA-AH, both in middle-aged mice (0.432 ± 0.063, P = 0.014) and senile mice (0.403 ± 0.145, P = 0.020) on diestrus, were significantly lower than that in young mice. The PR mRNA expression in middle-aged mice on proestrus (1.037 ± 0.037) was markedly lower than that in young mice (1.251 ± 0.081, P = 0.031) . In senile mice, the levels of Gnrh mRNA (1.520 ± 0.146, P = 0.004) and ERß mRNA (1.572 ± 0.184, P = 0.011) increased in POA-AH compared with that in young mice on metestrus. Aging had no effect upon KISS1 and KISS1r mRNA levels in POA-AH. In contrast, KISS1 mRNA level of MBH in middle-aged (1.663 ± 0.398, P = 0.037) and senile (2.622 ± 0.454, P = 0.014) mice obviously increased compared with the young mice group. CONCLUSION: Higher levels of ERα mRNA and decreases of PR and Gnrh mRNA in POA-AH in middle-aged mice on proestrus may play an important role in declining reproductive function.

[The determination of phthalic acid esters in edible vegetable oils by gas chromatography-mass spectrometry].

OBJECTIVE: We aimed to establish a quantified method for the 17 phthalate acid esters (PAE) in edible vegetable oil by gas chromatography-mass spectrometry (GC-MS) with the pretreatment of acetonitrile extraction and silica/N-(n-propyl)ethylenediamine (silica/PSA) mixed solid phase extraction column and evaluated the PAE of 25 edible oil samples from supermarkets in Hangzhou city. METHODS: The internal standard solution (D4-DEHP) was added in edible vegetable oil sample. The analytes were extracted by acetonitrile with 1 min vortex, and centrifuged at 3050×g for 5 min. The supernatant was then cleaned with silica/PSA column, and eluted with acetonitrile. The elution was dried with N2 flow at 50°C and diluted to 1.0 ml with hexane. Then, 17 PAE were tested by GC-MS and quantified with internal standards. The repeatability and sensitivity of the assay were evaluated. PAE were then determined in 25 plastic buckets of edible vegetable oil from supermarkets in Hangzhou city. RESULTS: By the quantification of internal standard of D4-DEHP, a good linearity range of related 17 PAE was observed. The correlation coefficient was 0.994-1.000 and the standard lowest quantified level was 0.05-0.15 µg/ml. The spiking recoveries of 17 PAE were 78.3%-108.9% with the RSD of 4.3%-12.1% (n=6). The method detection limits were 0.1-0.2 mg/kg. In 25 plastic buckets of edible vegetable oil from Hangzhou, DMP, DEP, DIBP, DBP and DEHP were detected at the range of <0.1-1.8 mg/kg and the detection rates were 12% (3/25), 24% (6/25), 100% (25/25), 96% (24/25) and 100% (25/25), respectively. Other 12 PAE was not detected. For DBP with the level of <0.1 to 1.3 mg/kg, the results of 16% (4/25) samples exceeded the regular migrating limit of 0.3 mg/kg. For DEHP of <0.2-1.8 mg/kg, the data of 12% (3/25) samples were beyond the regular migrating limit of 1.5 mg/kg. CONCLUSION: The pretreatment by silica/PSA mixed solid phase extraction column can satisfy the PAE determination requirements in edible vegetable oils. The DMP, DIBP, DEP, DBP and DEHP were detected from the survey of 25 edible oil samples in Hangzhou city.

Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels in cultured rat hippocampal neurons.

AIM: To investigate the effect of ginsenoside Rb1 on voltage-gated calcium currents in cultured rat hippocampal neurons and the modulatory mechanism. METHODS: Cultured hippocampal neurons were prepared from Sprague Dawley rat embryos. Whole-cell configuration of the patch-clamp technique was used to record the voltage-gated calcium currents (VGCCs) from the hippocampal neurons,and the effect of Rb1 was examined. RESULTS: Rb1 (2-100 µmol/L) inhibited VGCCs in a concentration-dependent manner, and the current was mostly recovered upon wash-out. The specific L-type Ca(2+) channel inhibitor nifedipine (10 µmol/L) occluded Rb1-induced inhibition on VGCCs. Neither the selective N-type Ca(2+) channel blocker ω-conotoxin-GVIA (1 µmol/L), nor the selective P/Q-type Ca(2+) channel blocker ω-agatoxin IVA (30 nmol/L) diminished Rb1-sensitive VGCCs. Rb1 induced a leftward shift of the steady-state inactivation curve of I(Ca) to a negative potential without affecting its activation kinetics or reversal potential in the I-V curve. The inhibitory effect of Rb1 was neither abolished by the adenylyl cyclase activator forskolin (10 µmol/L), nor by the PKA inhibitor H-89 (10 µmol/L). CONCLUSION: Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels, without affecting the N-type or P/Q-type Ca(2+) channels in hippocampal neurons. cAMP-PKA signaling pathway is not involved in this effect.

Ginsenoside Rg1 attenuates ß-amyloid generation via suppressing PPARγ-regulated BACE1 activity in N2a-APP695 cells.

The level of ß-site APP-cleaving enzyme 1 (BACE1) has been documented to increase in the brains of patients with Alzheimer's disease, which has resulted in elevation of ß-amyloid (Aß) peptides. As a transcription factor binding site of the BACE1 promoter, peroxisome proliferator-activated receptor-γ (PPARγ) response element regulates the activity of the BACE1 promoter activity, indicating that PPARγ may become a potential target for Alzheimer's disease treatment. Recent studies have demonstrated that ginsenoside Rg1 which is an effective component of extracts of ginseng can prevent memory loss and improve cognitive function in a variety of animal models. However, the underlying mechanism remains unclear. In the present study, we found that Rg1 decreased the levels of Aß1₋40 and Aß1₋42 secreted in N2a-APP695 cells. The expression levels of both BACE1 mRNA and protein as well as ß-CTFs, a cleavaged C-terminal fragment of APP by BACE1, were reduced in cells treated with Rg1. Moreover, Rg1 treatment led to a translocation of PPARγ from cytoplasm to nuclear. Intriguingly, Rg1, like pioglitazone (a PPARγ agonist), suppressed BACE1 activity in N2a-APP695 cells, while its effect on BACE1 activity was attenuated by GW9662 (a PPARγ antagonist). These results indicate that Rg1 may be a PPARγ agonist to enhance the binding of nuclear PPARγ to the BACE1 promoter, which may in turn inhibit the transcription and translation of BACE1, suppress the activity of BACE1, and ultimately attenuate Aß generation. Therefore, ginsenoside Rg1 may serve as a promising agent in modulating Aß-related pathology in Alzheimer's disease.

[Involvement of Wnt/beta-catenin signaling in tripchlorolide protecting against oligomeric beta-amyloid-(1-42)-induced neuronal apoptosis].

This study is to explore whether the Wnt/beta-catenin signaling pathway is involved in the process of tripchlorolide (T4) protecting against oligomeric Abeta(1-42)-induced neuronal apoptosis. Primary cultured cortical neurons were used for the experiments on day 6 or 7. The oligomeric Abeta(1-42) (5 micromol x L(-1) for 24 h) was applied to induce neuronal apoptosis. Prior to treatment with Abeta(1-42) for 24 h, the cultured neurons were pre-incubated with T4 (2.5, 10, and 40 nmol x L(-1)), Wnt3a (Wnt signaling agonists) and Dkk1 (inhibitors) for indicated time. Then the cell viability, neuronal apoptosis, and protein levels of Wnt, glycogen synthase kinase 3beta (GSK3beta), beta-catenin and phospho-beta-catenin were measured by MTT assay, TUNEL staining and Western blotting, respectively. The result demonstrated that oligomeric Abeta(1-42) induced apoptotic neuronal cell death in a time- and dose-dependent manner. Pretreatment with T4 significantly increased the neuronal cell survival and attenuated neuronal apoptosis. Moreover, oligomeric Abeta(1-42)-induced phosphorylation of beta-catenin and GSK3beta was markedly inhibited by T4. Additionally, T4 stabilized cytoplasmic beta-catenin. These results indicate that tripchlorolide protects against the neurotoxicity of Abeta by regulating Wnt/beta-catenin signaling pathway. This may provide insight into the clinical application of tripchlorolide to Alzheimer's disease.

Effects of fish protein hydrolysate on growth performance and humoral immune response in large yellow croaker (Pseudosciaena crocea R.).

We investigated the effects of fish protein hydrolysate (FPH) on growth performance and humoral immune response of the large yellow croaker (Pseudosciaena crocea R.). One thousand and two hundred large yellow croakers [initial average weight: (162.75+/-23.85) g] were divided into four groups and reared in floating sea cages (3 m x 3 m x 3 m). The animals were fed with 4 diets: basal diet only (control) or diets supplemented with 5%, 10% and 15% (w/w) FPH. The results show that dietary FPH levels significantly influenced the growth and immunity of the large yellow croaker. Compared with the control group, total weight gain (TWG) in all treatment groups, relative weight gain (RWG) and specific growth rate (SGR) in fish fed with diets supplemented with 10% and 15% FPH were significantly increased (P<0.05). Similar results were observed in immune parameters [lysozyme activity, serum complements, immunoglobulin M (IgM)]. Lysozyme activity, complement C4 and IgM were also significantly increased (P<0.05) in fish fed with diets supplemented with 10% and 15% FPH, while complement C3 level was significantly increased (P<0.05) in all treatment groups. In general, with the supplementation of FPH, particularly at dose of 10%, the growth performance and immunity of the large yellow croaker can be improved effectively.

Neuroprotective role of tripchlorolide on inflammatory neurotoxicity induced by lipopolysaccharide-activated microglia.

A large body of evidence has suggested a strong association between neuroinflammation and the pathogenesis of many neurodegenerative diseases. Therefore, it is a good target for therapeutic treatment. So far, studies have proven anti-inflammatory herbal medicine and its constituents to be effective in slowing down the neurodegenerative process. The present study tested tripchlorolide, an extract of Tripterygium wilfordii Hook F (TWHF), as a novel agent to suppress inflammatory process in microglia. It showed this novel agent to be cytotoxic at a dose of 20-40 nM to primary microglia and BV-2 microglial cells but not to primary cortical neurons and Neuro-2A cells in vitro. Moreover, tripchlorolide protected primary cortical neurons and Neuro-2A cells from neuroinflammatory toxicity induced by the conditioned media from lipopolysaccharide (LPS)-stimulated microglia, which resulted in a significant decrease in their cell survival. The changes of the inflammatory mediators in this process were further investigated. In the LPS-stimulated microglia, the production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), nitric oxide (NO), prostaglandin E(2) (PGE(2)), and intracellular superoxide anion (SOA) was markedly attenuated by tripchlorolide at a dose of 1.25-10 nM in a dose-dependent manner. Furthermore, the production of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was also significantly inhibited by tripchlorolide in both mRNA and protein levels. These results suggest that tripchlorolide can protect neuronal cells via a mechanism involving inhibition of inflammatory responses of microglia to pathological stimulations. Therefore, it is potentially a highly effective therapeutic agent in treating neuroninflammatory diseases.

[Advances in the study of immunopharmacological effects and mechanisms of extracts of Tripterygium wilfordii Hook. f. in neuroimmunologic disorders].

Extracts of Chinese herb Tripterygium wilfordii Hook. f. (TWHF) have been found to have potent anti-inflammatory and immunosuppressive functions and widely used in China for treatment of rheumatoid arthritis. Also they have been considered to be the potential drugs in the treatment of tumor and acute graft rejections. With the progress of neuroimmunological research on neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson disease (PD) and multiple sclerosis (MS), the neuroprotective strategies to rescue neurons from immunological injury are currently being explored. Recently, studies have indicated that extracts of TWHF such as triptolide, tripchlorolide and (5R)-5-hydroxytriptolide are able to attenuate progression of these neuroimmunologic disorders in vitro and in vivo. Accumulating evidence has shown that they can promote neuronal survival and neurite growth and facilitate functional recovery of brain injury by invoking distinct mechanisms that are related to their neuroprotective roles as inhibitor of neuroinflammatory toxicity of activated-microglia, antioxidants, calcium channel blockers, neurotrophic actions, modulating T cell functions, inhibitor of transcriptional activation of NF-kappaB on genes and signaling. Significant pharmaceutical strategies against neuroimmunologic disorders will hopefully be discovered by understanding the valuable components of TWHF.

[Ginsenoside Rb1 attenuates beta-amyloid peptide(25-35) -induced hyperphosphorylation of tau protein through CDK5 signal pathway].

This study is to explore the effect of ginsenoside Rb1 on the process of beta-amyloid peptide(25-35) (Abeta(25-35)) -induced hyperphosphorylation of tau protein, and on the level of cyclin-dependent kinase 5 activator, p25/p35. Western blotting and/or immunocytochemical staining were used to detect the levels of phosphorylation of tau protein at the sites of Thr205, Ser396, Ser404 in hippocampal neurons, cdk5 and p25/p35. After exposure to Abeta(25-35) (20 micromol x L(-1)) for 12 h, the levels of tau protein phosphorylation at the sites of Thr205, Ser396, Ser404 were enhanced, the level of p25 was increased, but the level of protein cdk5 was not changed markedly. Pretreatment with ginsenoside Rb1 reduced Abeta(25-35) -induced hyperphosphorylation of tau protein and decreased the lever of p25, but had no effect on cdk5. Ginsenoside Rb1 can attenuate Abeta(25-35) -induced hyperphosphorylation of tau protein through CDK5 signal pathway.