Qiangji Decoction Alleviates Neurodegenerative Changes and Hippocampal Neuron Apoptosis Induced by D-Galactose via Regulating AMPK/SIRT1/NF-κB Signaling Pathway

Fucoidan Improves D-Galactose-Induced Cognitive Dysfunction by Promoting Mitochondrial Biogenesis and Maintaining Gut Microbiome Homeostasis

Recent studies have indicated that fucoidan has the potential to improve cognitive impairment. The objective of this study was to demonstrate the protective effect and possible mechanisms of fucoidan in D-galactose (D-gal)-induced cognitive dysfunction. Sprague Dawley rats were injected with D-galactose (200 mg/kg, sc) and administrated with fucoidan (100 mg/kg or 200 mg/kg, ig) for 8 weeks. Our results suggested that fucoidan significantly ameliorated cognitive impairment in D-gal-exposed rats and reversed histopathological changes in the hippocampus. Fucoidan reduced D-gal-induced oxidative stress, declined the inflammation level and improved mitochondrial dysfunction in hippocampal. Fucoidan promoted mitochondrial biogenesis by regulating the PGC-1α/NRF1/TFAM pathway, thereby improving D-gal-induced mitochondrial dysfunction. The regulation effect of fucoidan on PGC-1α is linked to the upstream protein of APN/AMPK/SIRT1. Additionally, the neuroprotective action of fucoidan could be related to maintaining intestinal flora homeostasis with up-regulation of Bacteroidota, Muribaculaceae and Akkermansia and down-regulation of Firmicutes. In summary, fucoidan may be a natural, promising candidate active ingredient for age-related cognitive impairment interventions.

SuanZaoRen decoction alleviates neuronal loss, synaptic damage and ferroptosis of AD via activating DJ-1/Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

SuanZaoRen Decoction (SZRD), a famous herbal prescription, and has been widely proven to have positive therapeutic effects on insomnia, depression and Alzheimer's disease (AD). However, the anti-AD molecular mechanism of SZRD remains to be further investigated.

AIM OF THE STUDY

To elucidate the molecular mechanism of SZRD's improvement in AD's neuronal loss, synaptic damage and ferroptosis by regulating DJ-1/Nrf2 signaling pathway.

MATERIALS AND METHODS

LC-MS/MS was used to detect the active ingredients from SZRD. APP/PS1 mice was treated with SZRD and a ferroptosis inhibitor (Liproxstatin-1), respectively. Upon the completion of behavioral tests, Nissl staining, FJB staining, Golgi staining, immunofluorescence, immunohistochemistry, and transmission electron microscopy were preformed to evaluate the effects of SZRD on neuronal loss, synaptic damage, Aβ deposition. Iron staining, transmission electron microscopy, and iron assay kit was performed to estimate the effects of SZRD on ferroptosis. SOD kit, MDA kit, GSH kit, and GSH/GSSG kit were utilized to measure the oxidative stress levels in the hippocampus. The protein expression of TfR1, FTH1, FTL, FPN1, DJ-1, Nrf2, GPX4, SLC7A11, and ACSL4 were detected by Western blot.

RESULTS

A total of 16 active ingredients were identified from SZRD extract. SZRD SZRD significantly alleviated learning and memory impairment in APP/PS1 mice. SZRD improved the hippocampal neuronal loss and degenerated neurons in APP/PS1 mice via inhibiting the Aβ deposit. SZRD mitigated the hippocampal synaptic damage in APP/PS1 mice. SZRD inhibited iron accumulation, and alleviated the oxidative stress level in the hippocampus of APP/PS1 mice. Meanwhile, SZRD could up-regulate the protein expression level of FPN1, DJ-1, Nrf2, GPX4 and SLC7A11 in the hippocampus, and inhibit TfR1, FTH1, FTL, and ACSL4 protein expression.

CONCLUSION

SZRD alleviated neuronal loss, synaptic damage and ferroptosis in AD via activating DJ-1/Nrf2 signaling pathway.

Geraniol attenuates oxidative stress and neuroinflammation-mediated cognitive impairment in D galactose-induced mouse aging model

D-galactose (D-gal) administration was proven to induce cognitive impairment and aging in rodents' models. Geraniol (GNL) belongs to the acyclic isoprenoid monoterpenes. GNL reduces inflammation by changing important signaling pathways and cytokines, and thus it is plausible to be used as a medicine for treating disorders linked to inflammation. Herein, we examined the therapeutic effects of GNL on D-gal-induced oxidative stress and neuroinflammation-mediated memory loss in mice. The study was conducted using six groups of mice (6 mice per group). The first group received normal saline, then D-gal (150 mg/wt) dissolved in normal saline solution (0.9%, w/v) was given orally for 9 weeks to the second group. In the III group, from the second week until the 10th week, mice were treated orally (without anesthesia) with D-gal (150 mg/kg body wt) and GNL weekly twice (40 mg/kg body wt) four hours later. Mice in Group IV were treated with GNL from the second week up until the end of the experiment. For comparison of young versus elderly mice, 4 month old (Group V) and 16-month-old (Group VI) control mice were used. We evaluated the changes in antioxidant levels, PI3K/Akt levels, and Nrf2 levels. We also examined how D-gal and GNL treated pathological aging changes. Administration of GNL induced a significant increase in spatial learning and memory with spontaneously altered behavior. Enhancing anti-oxidant and anti-inflammatory effects and activating PI3K/Akt were the mechanisms that mediated this effect. Further, GNL treatment upregulated Nrf2 and HO-1 to reduce oxidative stress and apoptosis. This was confirmed using 99mTc-HMPAO brain flow gamma bioassays. Thus, our data suggested GNL as a promising agent for treating neuroinflammation-induced cognitive impairment.

Research progress on rodent models and its mechanisms of liver injury

The liver is the most important organ for biological transformation in the body and is crucial for maintaining the body's vital activities. Liver injury is a serious pathological condition that is commonly found in many liver diseases. It has a high incidence rate, is difficult to cure, and is prone to recurrence. Liver injury can cause serious harm to the body, ranging from mild to severe fatty liver disease. If the condition continues to worsen, it can lead to liver fibrosis and cirrhosis, ultimately resulting in liver failure or liver cancer, which can seriously endanger human life and health. Therefore, establishing an rodent model that mimics the pathogenesis and severity of clinical liver injury is of great significance for better understanding the pathogenesis of liver injury patients and developing more effective clinical treatment methods. The author of this article summarizes common chemical liver injury models, immune liver injury models, alcoholic liver injury models, drug-induced liver injury models, and systematically elaborates on the modeling methods, mechanisms of action, pathways of action, and advantages or disadvantages of each type of model. The aim of this study is to establish reliable rodent models for researchers to use in exploring anti-liver injury and hepatoprotective drugs. By creating more accurate theoretical frameworks, we hope to provide new insights into the treatment of clinical liver injury diseases.

Lead exposure induces neuronal apoptosis via NFκB p65/RBBP4/Survivin signaling pathway

Lead (Pb), as a heavy metal that is easily exposed in daily life, can cause damage to various systems of body. Apoptosis is an autonomous cell death process regulated by genes in order to maintain the stability of internal environment, which plays an important role in the development of nervous system. RB binding protein 4 (RBBP4) is one of the core histone binding subunits and is closely related to the apoptosis process of nervous system cells. However, it is not known whether RBBP4 can regulate neuronal apoptosis in lead-exposed environments. We exposed PC12 cells to 0 μM (control group), 1 μM, and 100 μM PbAc for 24 h to obtain cell samples. The female rats ingested drinking water containing 0, 0.5 g/L, and 2.0 g/L PbAc from the first day of pregnancy to three weeks after delivery to obtain hippocampal tissue samples from mammary rats. The results of TUNEL showed that lead exposure promoted the onset of apoptosis in cells and hippocampus. The mRNA and protein levels of the apoptosis-related protein Survivin were significantly reduced in the lead-exposed group compared to the control group. In addition, we found that lead exposure reduces the mRNA and protein levels of RBBP4 in PC12 cells and hippocampus, and increases the mRNA and protein levels of NFκB p65. Moreover, inhibiting NFκB p65 can reverse the decrease in RBBP4 expression in the lead exposure model. Overexpression of RBBP4 increased Survivin expression and reduced apoptosis induced by lead exposure. This suggests that lead exposure induces apoptosis through the NFκB p65/RBBP4/Survivin signaling pathway.

Aerobic exercise mitigates hippocampal neuronal apoptosis by regulating DAPK1/CDKN2A/REDD1/FoXO1/FasL signaling pathway in D-galactose-induced aging mice

Brain aging is the most important risk factor for neurodegenerative disorders, and abnormal apoptosis is linked to neuronal dysfunction. Specifically, studies have found that exercise effectively inhibits hippocampal neuronal apoptosis, while the molecular mechanism remains unclear. In the present study, we investigated the impact of aerobic exercise on hippocampal neuronal apoptosis in aging mice and the potential involvement of DAPK1 and its downstream pathways based on recent data that DAPK1 may be associated with neuronal death in neurodegenerative diseases. Senescent mice were subjected to 8 weeks of Aerobic training. Following behavioral testing, hippocampal samples were examined histologically and biochemically to detect pathological changes, neuronal apoptosis, and mRNA and protein levels. We found that the exercise intervention improved spatial memory and alleviated neuronal apoptosis in the brain. Notably, exercise down-regulated DAPK1 expression and inhibited Fas death receptor transactivation and the mitochondrial apoptotic pathway in the hippocampus. These results shed new light on the protective effect of regular exercise against brain aging though modulating the DAPK1 pathway.

Acetyl-11-keto-beta boswellic acid(AKBA) modulates CSTC-pathway by activating SIRT-1/Nrf2-HO-1 signalling in experimental rat model of obsessive-compulsive disorder: Evidenced by CSF, blood plasma and histopathological alterations

Obsessive-Compulsive disorder (OCD) is a long-term and persistent mental illness characterised by obsessive thoughts and compulsive behaviours. Numerous factors can contribute to the development or progression of OCD. These factors may result from the dysregulation of multiple intrinsic cellular pathways, including SIRT-1, Nrf2, and HO-1. Inhibitors of selective serotonin reuptake (SSRIs) are effective first-line treatments for OCD. In our ongoing research, we have investigated the role of SIRT-1, Nrf2, and HO-1, as well as the neuroprotective potential of Acetyl-11-keto-beta boswellic acid (AKBA) against behavioural and neurochemical changes in rodents treated with 8-OH-DPAT. In addition, the effects of AKBA were compared to those of fluvoxamine (FLX), a standard OCD medication. Injections of 8-OH-DPAT into the intra-dorso raphe nuclei (IDRN) of rats for seven days induced repetitive and compulsive behaviour accompanied by elevated oxidative stress, inflammatory processes, apoptosis, and neurotransmitter imbalances in CSF, blood plasma, and brain samples. Chronic administration of AKBA at 50 mg/kg and 100 mg/kg p.o. restored histopathological alterations in the cortico-striatal-thalamo-cortical (CSTC) pathway, including the cerebral cortex, striatum, and hippocampal regions. Our investigation revealed that when AKBA and fluvoxamine were administered together, the alterations were restored to a greater degree than when administered separately. These findings demonstrate that the neuroprotective effect of AKBA can serve as an effective basis for developing a novel OCD treatment.

Astragaloside IV ameliorates cognitive impairment and protects oligodendrocytes from antioxidative stress via regulation of the SIRT1/Nrf2 signaling pathway

Subcortical ischemic vascular dementia (SIVD), which is caused by chronic cerebral hypoperfusion, is a common subtype of vascular dementia, accompanied by white matter damage and cognitive impairment. Currently, there are no effective treatments for this condition. Oxidative stress is a key factor in the pathogenesis of white matter damage. Astragaloside IV (AS-IV), one of the main active components of astragaloside, has antioxidant properties and promotes cognitive improvement; however, its effect on SIVD and its potential mechanism remain unknown. We aimed to clarify whether AS-IV had a protective effect against SIVD injury caused by right unilateral common carotid artery occlusion and the underlying mechanism. The results showed that AS-IV treatment improved cognitive function and white matter damage, inhibited oxidative stress and glial cells activation, and promoted the survival of mature oligodendrocytes after chronic cerebral hypoperfusion. Moreover, the protein expression levels of NQO1, HO-1, SIRT1 and Nrf2 were increased by AS-IV treatment. However, pre-treatment with EX-527, a SIRT1-specific inhibitor, eliminated the beneficial effects of AS-IV. These results demonstrate that AS-IV plays a neuroprotective role in SIVD by suppressing oxidative stress and increasing the number of mature oligodendrocytes via the modulation of SIRT1/Nrf2 signaling. Our results support AS-IV as a potential therapeutic agent for SIVD.

Cognitive improvement via a modulated rhythmic pulsed magnetic field in D-galactose-induced accelerated aging mice

Rhythmic physical stimulations have emerged as effective noninvasive intervention strategies in the treatment of pathological cognitive deficits. Transcranial magnetic stimulation (TMS) can regulate neural firing and improve the learning and memory abilities of rodents or patients with cognitive deterioration. However, the effects of elaborate magnetic stimulation with low intensity during aging or other neurological disordering processes on cognitive decline remain unclear. In this study, we developed an elaborate modulated pulsed magnetic field (PMF) stimulation with a complex pattern in the theta repeated frequency and gamma carrier frequency and then determined the effects of this rhythmic PMF on the cognitive function of accelerated aging mice established by chronic subcutaneous injection of D-galactose (D-gal). The results of the Morris water maze (MWM) test showed that mice treated with modulated PMF displayed shorter swimming distance and latency time in the spatial exploration acquisition trial and exhibited a significant preference in the target presumptive platform area in the probe trial, all of which indicated the enhancement in spatial learning and memory abilities upon PMF stimulation of the accelerated aging mice. The novel object recognition (NOR) test results showed a similar tendency as the MWM results although without statistical significance. Further determination of histological structures demonstrated that the cognitive function-related hippocampal CA3 neurons degenerated upon D-gal injection, which could also be partially rescued by PMF application. In comparison with the high-intensity TMS approach, low-intensity magnetic stimulation could be much safer and allow deeper penetration without adverse effects such as seizure. In summary, modulated PMF, even with low intensity, could effectively improve rodent cognitive functions impaired by D-gal-induced accelerated aging, which might provide a new safe therapeutic strategy for cognitive deficits as well as other neurological disorders.

Artesunate Combined With Metformin Ameliorate on Diabetes-Induced Xerostomia by Mitigating Superior Salivatory Nucleus and Salivary Glands Injury in Type 2 Diabetic Rats via the PI3K/AKT Pathway

Polydipsia and xerostomia are the most common complications that seriously affect oral health in patients with diabetes. However, to date, there is no effective treatment for diabetic xerostomia. Recent studies have reported that artesunate (ART) and metformin (Met) improve salivary gland (SG) hypofunction in murine Sjögren's syndrome. Therefore, aim of this study was to investigate the effect and underlying mechanism of artesunate (ART) alone and in combination with metformin (Met) on hyposalivation in type 2 diabetes mellitus (T2DM) rats. T2DM rats were induced using a high-fat diet and streptozotocin. SPF male Sprague-Dawley rats were divided into the following five groups: normal control group, untreated diabetic group, ART-treated diabetic group (50 mg/kg), Met-treated diabetic group (150 mg/kg), and ART/Met co-treated diabetic group (50 mg/kg ART and 150 mg/kg Met). ART and Met were intragastrically administered daily for 4 weeks. The general conditions, diabetes parameters and serum lipids were evaluated after drug treatment. Furthermore, we observed changes in the central superior salivatory nucleus (SSN) and SG, and changes in the AQP5 expression, parasympathetic innervation (AChE and BDNF expression), and PI3K/AKT pathway- (p-AKT, and p-PI3K), apoptosis- (Bax, Bcl-2, and Caspase3), and autophagy- (LC3 and P62) related markers expression in T2DM rats after treatment. Our results showed that ART or Met alone and ART/Met combination attenuated a range of diabetic symptoms, including weight loss, urine volume increase, water consumption increase, hyperglycemia, insulin resistance, glucose intolerance and dyslipidemia. More importantly, we found that these three treatments, especially ART/Met combination, mitigated hyposalivation in the T2DM rats via improving the central SSN and SGs damage in hyperglycemia. Our data also indicated that ART/Met attenuated SG damage though regulating the PI3K/Akt pathway to inhibit apoptosis and autophagy of SGs in the T2DM rats. Moreover, ART/Met preserved parasympathetic innervation (AChE and BDNF expression) in SGs to alleviate diabetes-induced hyposalivation likely through rescuing central SSN damage. Taken together, these findings might provide a novel rationale and treatment strategy for future treatment of diabetes-induced xerostomia in the clinic.