NaoXinTong Inhibits the Development of Diabetic Retinopathy in db/db Mice

The Therapeutic Effect and Mechanism of Traditional Chinese Medicine in Type 2 Diabetes Mellitus and Its Complications

Traditional Chinese Medicine (TCM) has recently emerged as a beacon for the treatment of diabetes and its complications. Many TCMs that are commonly used, have the potentially demonstrated significant anti-diabetic effects. The mechanisms of these effects have been extensively discussed using modern techniques, such as genomics, mass spectrometry, and network pharmacology. Studies have demonstrated that TCM can influence glucose metabolism and pancreatic function via a diverse array of mechanisms including PI3K/AKT and AMPK pathways. TCM not only exhibits potential in the treatment of diabetes but also reduces the risk of diabetic complications. It is effective in the treatment of diabetic nephropathy (DN), diabetic retinopathy (DR), diabetic neuropathy (DPN), diabetic cardiomyopathy, and peripheral angiopathy. Research has demonstrated that prescriptions, Chinese herbal medicines, and their extracts play a role in a variety of molecular mechanisms such as antioxidation, apoptosis regulation, hypoxia improvement, autophagy, and promotion of glucose and lipid metabolism. The antioxidant properties of TCM have received considerable attention. Recent studies have demonstrated that they are capable of effectively eliminating free radicals from the body and reducing damage to cells caused by oxidative stress. Consequently, they are crucial in the treatment of diabetes and its associated complications. This review summarizes the ever-expanding scope of TCM applicability in the field of diabetes, providing crucial support and innovative ideas for modern healthcare. TCMs could help seek more effective pharmacological targets in basic study and as well serve as the complement to the strategy of diabetic prevention and treatment benefiting the patients. More and more large series of RCT and clinical investigations will eventually examine the efficacy of specific TCM formulas on the therapeutic effect of DM and its complication where currently treatments could not be satisfied.

Incidence of microvascular dysfunction is increased in hyperlipidemic mice, reducing cerebral blood flow and impairing remote memory

Introduction

The development of cognitive dysfunction is not necessarily associated with diet-induced obesity. We hypothesized that cognitive dysfunction might require additional vascular damage, for example, in atherosclerotic mice.

Methods

We induced atherosclerosis in male C57BL/6N mice by injecting AAV-PCSK9DY (2x1011 VG) and feeding them a cholesterol-rich Western diet. After 3 months, mice were examined for cognition using Barnes maze procedure and for cerebral blood flow. Cerebral vascular morphology was examined by immunehistology.

Results

In AAV-PCSK9DY-treated mice, plaque burden, plasma cholesterol, and triglycerides are elevated. RNAseq analyses followed by KEGG annotation show increased expression of genes linked to inflammatory processes in the aortas of these mice. In AAV-PCSK9DY-treated mice learning was delayed and long-term memory impaired. Blood flow was reduced in the cingulate cortex (-17%), caudate putamen (-15%), and hippocampus (-10%). Immunohistological studies also show an increased incidence of string vessels and pericytes (CD31/Col IV staining) in the hippocampus accompanied by patchy blood-brain barrier leaks (IgG staining) and increased macrophage infiltrations (CD68 staining).

Discussion

We conclude that the hyperlipidemic PCSK9DY mouse model can serve as an appropriate approach to induce microvascular dysfunction that leads to reduced blood flow in the hippocampus, which could explain the cognitive dysfunction in these mice.

Integrated metabolomics and gut microbiome to the effects and mechanisms of naoxintong capsule on type 2 diabetes in rats

Naoxintong Capsule (NXT) is a Traditional Chinese Medicine formulation which has been widely applied in treating cardiovascular and cerebrovascular diseases. Previous studies also reported the potential effects of NXT against diabetes and certain complications, yet its mechanisms remain largely obscured. Herein, in this study, we investigated the anti-diabetic effects of NXT as well as its potential mechanisms. Type 2 diabetes (T2D) was induced in rats by 10-week high-fat diet in companion with a low-dose streptozotocin injection. NXT was administrated for additional 8 weeks. The results showed that NXT exerted potent efficacy against T2D by alleviating hyperglycemia and hyperlipidemia, ameliorating insulin resistance, mitigating inflammation, relieving hypertension, and reducing myocardial injuries. To investigate its mechanisms, by integrating sequencing of gut microbiota and serum untargeted metabolomics, we showed that NXT could significantly recover the disturbances of gut microbiota and metabolic phenotypes in T2D rats. Several feature pathways, such as arachidonic acid metabolism, fatty acid β-oxidation and glycerophospholipid metabolism, were identified as the potential mechanisms of NXT in vivo. In summary, our study has comprehensively revealed the anti-diabetic effects of NXT which could be considered as a promising strategy for treating metabolic disorders, T2D and diabetic related complications in clinical practice.

Effect of Naoxintong Capsules on the Activities of CYP450 and Metabolism of Metoprolol Tartrate in Rats Evaluated by Probe Cocktail and Pharmacokinetic Methods

Naoxintong capsule (NXT), a prescribed Chinese medicine, has been used clinically for more than 20 years and is widely received by patients. We determined five probe drugs, namely, omeprazole (CYP2C19), midazolam (CYP3A4), phenacetin (CYP1A2), tolbutamide (CYP2C9), and dextromethorphan (CYP2D6) to study the potential influences of NXT on the activities of CYP enzymes and assessed the pharmacokinetics effect of NXT on metoprolol tartrate in rat plasma. The study showed that AUC_(0–24) and AUC_(0–∞) of midazolam (CYP3A4) in NXT coadministration group (283.7 ± 65.2 h·ng·mL⁻¹ and 292.0 ± 75.1 h·ng·mL⁻¹ in group B; 295.7 ± 62.7 h·ng·mL⁻¹ and 299.5 ± 60.0 h·ng·mL⁻¹ in group C) were significantly decreased as compared to another group (416.8 ± 82.3 h·ng·mL⁻¹ and 424.9 ± 77.9 h·ng·mL⁻¹ in group A), while that of dextromethorphan (CYP2D6) showed an opposite tendency (540.7 ± 119.7 h·ng·mL⁻¹ and 595.3 ± 122.2 h·ng·mL⁻¹ in group A, 760.6 ± 184.9 h·ng·mL⁻¹ and 788.7 ± 211.0 h·ng·mL⁻¹ in group B, and 734.3 ± 118.5 h·ng·mL⁻¹ and 757.2 ± 105.4 h·ng·mL⁻¹ in group C). Moreover, NXT preadministration can enhance the metabolism of metoprolol tartrate and reduce the metabolism of O-demethylmetoprolol. The results indicated that NXT had potential effects in inducing CYP3A4 and inhibiting CYP2D6 in the metabolism of metoprolol tartrate. It suggests that patients who coadministered NXT and metoprolol tartrate should be advised of potential herb-drug interactions (HDIs) to reduce therapeutic failure or accelerated toxicity of conventional drug treatment.

NaoXinTong Capsules inhibit the development of diabetic nephropathy in db/db mice

NaoXinTong Capsule (NXT), a Chinese medicine, is currently used to treat patients with cardiovascular and cerebrovascular diseases. Clinical observations indicate its anti-diabetic functions with unclear mechanisms. Herein, we report the effect of NXT on diabetic nephropathy (DN). Type 2 diabetic db/db mice were treated with NXT for 14 weeks. In the course of treatment, NXT reduced diabetes-increased glucose levels and improved renal functions. At the end of treatment, we found that NXT ameliorated serum lipid profiles and other biochemical parameters. In the kidney, NXT inhibited mesangial matrix expansion, expression of vascular endothelial growth factor A, fibronectin, advanced glycation end product and its receptor. Meanwhile, it reduced the diabetes-induced podocyte injury by increasing WT1 and nephrin expression. In addition, NXT inhibited accumulation of extracellular matrix proteins by increasing MMP2/9 expression through inactivation of TGFβ/Smad pathway and CTGF expression. Mechanically, NXT activated insulin signaling pathway by increasing expression of INSR, IRS and FGF21, phosphorylation of Akt and AMPKα in the liver, INSR phosphorylation in the kidney, and FGF21 and GLUT4 expression in adipose tissue and skeletal muscle. Taken together, our study demonstrates that NXT inhibits DN by ameliorating glucose/lipid metabolism, maintaining tissue structure integrity, and correcting diabetes-induced renal dysfunctions.

Pharmacokinetics of Caffeic Acid, Ferulic Acid, Formononetin, Cryptotanshinone, and Tanshinone IIA after Oral Administration of Naoxintong Capsule in Rat by HPLC-MS/MS

Naoxintong capsule (NXTC) was a famous patent medicine of Traditional Chinese Medicine (TCM) to treat cerebrovascular diseases in China. An LC-MS/MS method was developed for simultaneous determination of 11 major ingredients (paeoniflorin, ecdysterone, amygdalin, mulberroside A, caffeic acid, ferulic acid, salvianolic acid B, astragaloside IV, formononetin, cryptotanshinone, and tanshinone IIA) in NXTC in rat plasma. All analytes were separated on an Eclipse plus C₁₈ column using a gradient mobile phase system of acetonitrile-0.1% formic acid aqueous solution. The lower limits of quantification of 11 ingredients were between 0.075 and 10 ng mL⁻¹. The precision was less than 15% and the accuracies were between 85% and 115%. The results showed that caffeic acid, ferulic acid, formononetin, cryptotanshinone, and tanshinone IIA could be detected after oral administration of NXTC. The validated method was successfully applied to pharmacokinetic study of the caffeic acid, ferulic acid, formononetin, cryptotanshinone, and tanshinone IIA in rats after oral administration of NXTC at single and triple dose.

Thioredoxin plays a key role in retinal neuropathy prior to endothelial damage in diabetic mice

Diabetes is a chronic metabolic syndrome that results in changes in carbohydrate, lipid and protein metabolism. With diabetes for a long time, it increases the risk of diabetic retinopathy (DR) and long-term morbidity and mortality. Moreover, emerging evidence suggests that neuron damage occurs earlier than microvascular complications in DR patients, but the underlying mechanism is unclear. We investigated diabetes-induced retinal neuropathy and elucidated key molecular events to identify new therapeutic targets for the clinical treatment and prevention of DR. For in vivo studies, a high-fat diet and streptozotocin (STZ) injection were used to generate the diabetes model. Hematoxylin-eosin staining was used for morphological observations and measurements of the outer nuclear layer thickness. Electroretinography (ERG) was used to assess retinal function. For in vitro studies, Neuro2a cells were incubated in normal (5.5 mM) and high-glucose (30 mM) conditions. Flow cytometry assays were performed to analyze apoptosis. Additionally, real-time PCR and Western blotting analyses were carried out to determine gene and protein expression in vitro and in vivo. Taken together, the results indicated that retinal neuropathy occurred prior to endothelial damage induced by diabetes, and thioredoxin (Trx) plays a key role in this process. This underlying mechanism may be related to activation of the Trx/ASK1/p-p38/Trx-interacting protein pathway.

Myricitrin Alleviates Oxidative Stress-induced Inflammation and Apoptosis and Protects Mice against Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) has been increasingly considered as a main cause of heart failure and death in diabetic patients. At present, no effective treatment exists to prevent its development. In the present study, we describe the potential protective effects and mechanisms of myricitrin (Myr) on the cardiac function of streptozotosin-induced diabetic mice and on advanced glycation end products (AGEs)-induced H9c2 cardiomyocytes. In vitro experiments revealed that pretreatment with Myr significantly decreased AGEs-induced inflammatory cytokine expression, limited an increase in ROS levels, and reduced cell apoptosis, fibrosis, and hypertrophy in H9c2 cells. These effects are correlated with Nrf2 activation and NF-κB inhibition. In vivo investigation demonstrated that oral administration of Myr at 300 mg/kg/day for 8 weeks remarkably decreased the expression of enzymes associated with cardiomyopathy, as well as the expression of inflammatory cytokines and apoptotic proteins. Finally, Myr improved diastolic dysfunction and attenuated histological abnormalities. Mechanistically, Myr attenuated diabetes-induced Nrf2 inhibition via the regulation of Akt and ERK phosphorylation in the diabetic heart. Collectively, these results strongly indicate that Myr exerts cardioprotective effects against DCM through the blockage of inflammation, oxidative stress, and apoptosis. This suggests that Myr might be a potential therapeutic agent for the treatment of DCM.

Naoxintong Protects Primary Neurons from Oxygen-Glucose Deprivation/Reoxygenation Induced Injury through PI3K-Akt Signaling Pathway

Naoxintong capsule (NXT), developed from Buyang Huanwu Decoction, has shown the neuroprotective effects in cerebrovascular diseases, but the neuroprotection mechanisms of NXT on ischemia/reperfusion injured neurons have not yet been well known. In this study, we established the oxygen-glucose deprivation/reoxygenation (OGD/R) induced neurons injury model and treat the neurons with cerebrospinal fluid containing NXT (BNC) to investigate the effects of NXT on OGD/R induced neurons injury and potential mechanisms. BNC improved neuron viability and decreased apoptotic rate induced by OGD/R. BNC attenuated OGD/R induced cytosolic and mitochondrial Ca(2+) overload, ROS generation, intracellular NO levels and nNOS mRNA increase, and cytochrome-c release when compared with OGD/R group. BNC significantly inhibited both mPTP opening and ΔΨm depolarization. BNC increased Bcl-2 expression and decreased Bax expression, upregulated the Bcl-2/Bax ratio, downregulated caspase-3 mRNA and caspase-9 mRNA expression, and decreased cleaved caspase-3 expression and caspase-3 activity. BNC increased phosphorylation of Akt following OGD/R, while LY294002 attenuated BNC induced increase of phosphorylated Akt expression. Our study demonstrated that NXT protected primary neurons from OGD/R induced injury by inhibiting calcium overload and ROS generation, protecting mitochondria, and inhibiting mitochondrial apoptotic pathway which was mediated partially by PI3K-Akt signaling pathway activation.