Streptozotocin-induced Diabetic Mice Research Articles

Characterization and evaluation of the in vitro and in vivo anti-diabetic activities of camel milk protein hydrolysates derived with different protease digestions

The study aimed to determine the potential anti-diabetic activities of the hydrolysates of camel milk proteins (CMPH). Camel milk proteins were hydrolyzed independently by using 11 proteases, and their anti-diabetic activities were analyzed by in vitro, and in vivo. The results showed that CMPH-Flavourzyme exhibited the best α-glucosidase and dipeptidyl peptidase-IV inhibitory activity, while CMPH-Papain exhibited the highest α-amylase inhibitory activity, and best proliferative effect on streptozotocin-induced NIT-1 cells in vitro. Furthermore, CMPH-Papain exhibited the most effect in decreasing the serum levels of fasting blood glucose, oral glucose tolerance test, pro-inflammatory factors (IL-1β, IL-6) and triglyceride, as well as increasing insulin levels on in vivo streptozotocin-induced diabetic mice. Peptides identification followed with molecular docking and network pharmacology analysis also found the potential anti-diabetic peptides from CMPH-Flavourzyme and CMPH-Papain. Our results indicated the type of protease used for the treatment significantly influences the anti-diabetic activities of the resulting CMPH.

Impaired distal renal potassium handling in streptozotocin-induced diabetic mice.

Diabetes is closely associated with K+ disturbances during disease progression and treatment. However, it remains unclear whether K+ imbalance occurs in diabetes with normal kidney function. In this study, we examined the effects of dietary K+ intake on systemic K+ balance and renal K+ handling in streptozotocin (STZ)-induced diabetic mice. The control and STZ mice were fed low or high K+ diet for 7 days to investigate the role of dietary K+ intake in renal K+ excretion and K+ homeostasis, and to explore the underlying mechanism by evaluating K+ secretion-related transport proteins in distal nephrons. K+-deficient diet caused excessive urinary K+ loss, decreased daily K+ balance, and led to severe hypokalemia in STZ mice compared to control mice. In contrast, STZ mice showed an increased daily K+ balance and elevated plasma K+ level under K+-loading conditions. Dysregulation of the NaCl cotransporter (NCC), epithelia Na+ channel (ENaC), and renal outer medullary K+ channel (ROMK) was observed in diabetic mice fed either low or high K+ diet. Moreover, amiloride treatment reduced urinary K+ excretion and corrected hypokalemia in K+-restricted STZ mice. On the other hand, inhibition of SGLT2 by dapagliflozin promoted urinary K+ excretion and normalized plasma K+ level in K+-supplemented STZ mice, at least partly by increasing ENaC activity. We conclude that STZ mice exhibited abnormal K+ balance and impaired renal K+ handling under either low or high K+ diet, which could be primarily attributed to the dysfunction of ENaC-dependent renal K+ excretion pathway, despite the possible role of NCC.

Evaluation of antioxidant and antihyperglycemic effects Dovyalis Abyssinica (A.Rich)

BackgroundThe leaves of Dovyalis Abyssinica have been used traditionally for the management of diabetes mellitus. Thus, this study aimed to evaluate the Antioxidant and Antihyperglycemic Effects of Dovyalis Abyssinica leaves crude extract in streptozotocin-induced diabetic mice. MethodsTo Evaluate the Antihyperglycemic, and Antioxidant Effects of Dovyalis Abyssinica Leaves Extract in Streptozotocin-Induced Diabetic Mice. Male Swiss albino mice were induced into diabetes using 100 mg/kg of streptozotocin. Mice were allocated randomly into six groups, six mice per group. The body weight and FBG measurements were done on days 0, 7th, 14th and 21st of treatment. Additionally, in vitro Antioxidant Activity of the Extract was determined using a DPPH assay. The data were entered into Epi-Data version 4.6, exported to SPSS version 26.0, and analysed by using a one-way ANOVA followed by a Tukey post hoc test, and P < 0.05 was considered statistically significant. ResultsDovyalis Abyssinica leaves crude extract showed significant (P < 0.05-P< 0.001) blood-glucose-lowering activity. Moreover, the crude extract of D. abyssinica reduced the fasting blood glucose level by 45.13 %, 52.51 %, 54.85 %, and 56.38 %, respectively, for DA 100, DA 200, DA 400, and GLC 5 mg/kg on the 21st day of treatment. After diabetic mice were treated with Dovyalis Abyssinica (100, 200, and 400 mg/kg) for 21 days, there was a significant increase in body weight as compared to diabetic control. Antioxidant activities of the leaf extract was found to be comparable to ascorbic acid with an IC50 of 140.04 μg/ml. ConclusionThe present findings revealed that D. abyssinica leaves could be useful for the management of diabetes mellitus and other abnormalities related to this metabolic disorder. Thus, the present study may support the traditional use of D. abyssinica for diabetes mellitus treatment.

Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice.

Islet transplantation (ITx) is an established and safe alternative to pancreas transplantation for type 1 diabetes mellitus (T1DM) patients. However, most ITx recipients lose insulin independence by 3 years after ITx due to early graft loss, such that multiple donors are required to achieve insulin independence. In the present study, we investigated whether skeletal myoblast cells could be beneficial for promoting angiogenesis and maintaining the differentiated phenotypes of islets. In vitro experiments showed that the myoblast cells secreted angiogenesis-related cytokines (vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and stromal-derived factor-1α (SDF-1α)), contributed to maintenance of differentiated islet phenotypes, and enhanced islet cell insulin secretion capacity. To verify these findings in vivo, we transplanted islets alone or with myoblast cells under the kidney capsule of streptozotocin-induced diabetic mice. Compared with islets alone, the group bearing islets with myoblast cells had a significantly lower average blood glucose level. Histological examination revealed that transplants with islets plus myoblast cells were associated with a significantly larger insulin-positive area and significantly higher number of CD31-positive microvessels compared to islets alone. Furthermore, islets cotransplanted with myoblast cells showed JAK-STAT signaling activation. Our results suggest two possible mechanisms underlying enhancement of islet graft function with myoblast cells cotransplantation: "indirect effects" mediated by angiogenesis and "direct effects" of myoblast cells on islets via the JAK-STAT cascade. Overall, these findings suggest that skeletal myoblast cells enhance the function of transplanted islets, implying clinical potential for a novel ITx procedure involving myoblast cells for patients with diabetes.

IL-10-induced modulation of macrophage polarization suppresses outer-blood-retinal barrier disruption in the streptozotocin-induced early diabetic retinopathy mouse model.

Diabetic retinopathy (DR) is associated with ocular inflammation leading to retinal barrier breakdown, vascular leakage, macular edema, and vision loss. DR is not only a microvascular disease but also involves retinal neurodegeneration, demonstrating that pathological changes associated with neuroinflammation precede microvascular injury in early DR. Macrophage activation plays a central role in neuroinflammation. During DR, the inflammatory response depends on the polarization of retinal macrophages, triggering pro-inflammatory (M1) or anti-inflammatory (M2) activity. This study aimed to determine the role of macrophages in vascular leakage through the tight junction complexes of retinal pigment epithelium, which is the outer blood-retinal barrier (BRB). Furthermore, we aimed to assess whether interleukin-10 (IL-10), a representative M2-inducer, can decrease inflammatory macrophages and alleviate outer-BRB disruption. We found that modulation of macrophage polarization affects the structural and functional integrity of ARPE-19 cells in a co-culture system under high-glucose conditions. Furthermore, we demonstrated that intravitreal IL-10 injection induces an increase in the ratio of anti-inflammatory macrophages and effectively suppresses outer-BRB disruption and vascular leakage in a mouse model of early-stagestreptozotocin-induced diabetes. Our results suggest that modulation of macrophage polarization by IL-10 administration during early-stage DR has a promising protective effect against outer-BRB disruption and vascular leakage. This finding provides valuable insights for early intervention in DR.

Polysaccharide extracted from Sarcandra glabra residue attenuate cognitive impairment by regulating gut microbiota in diabetic mice

Diabetic encephalopathy (DE), characterized by cognitive impairment, currently lacks targeted treatment. Previous studies have shown that Sarcandra glabra extracted residue polysaccharide (SERP) exhibited hypoglycemic effects either in vitro or in streptozotocin-induced diabetes mice. However, the therapeutic effect of SERP on DE was not elucidated. This study investigated the therapeutic effect of SERP on DE and its underlying mechanism. Our results revealed that SERP regulates glucose and lipid metabolism, improves cognitive function, and exhibits diminished activity post-antibiotic intervention. Importantly, we discovered a novel mechanism by which SERP modulates the gut microbiota, specifically enriching Bacteroidales S24-7, resulting in elevated levels of butyric acid in the intestine. This regulation modulates the intestinal endocrine cell lipid metabolism level, restores damaged intestinal barriers and neural epithelial circuits, thus exhibiting cure effects. Our findings suggest that SERP could become a candidate for treating DE, potentially involving the regulation mechanism of the “microbiota-gut-brain axis”. This study underscores the unique therapeutic efficacy of SERP in managing DE, offering fresh drug candidates and innovative treatment strategies for this challenging condition.

Capsaicin reduces blood glucose and prevents prostate growth by regulating androgen, RAGE/IGF-1/Akt, TGF-β/Smad signalling pathway and reversing epithelial-mesenchymal transition in streptozotocin-induced diabetic mice.

Type 2 diabetes mellitus (T2DM) is a metabolic disease. Diabetes increases the risk of benign prostatic hyperplasia (BPH). Capsaicin is extracted from chili peppers and possesses many pharmacological properties, including anti-diabetic, pain-relieving, and anti-cancer properties. This study aimed to investigate the effects of capsaicin on glucose metabolism and prostate growth in T2DM mice and uncover the related mechanisms. Mice model of diabetes was established by administering a high-fat diet and streptozotocin. Oral administration of capsaicin for 2weeks inhibited prostate growth in testosterone propionate (TP)-treated mice. Furthermore, oral administration of capsaicin (5mg/kg) for 2weeks decreased fasting blood glucose, prostate weight, and prostate index in diabetic and TP-DM mice. Histopathological alterations were measured using hematoxylin & eosin (H&E) staining. The protein expression of 5α-reductase type II, androgen receptor (AR), and prostate-specific antigen (PSA) were upregulated in diabetic and TP-DM mice, but capsaicin reversed these effects. Capsaicin decreased the protein expression of p-AKT, insulin-like growth factor-1 (IGF-1), IGF-1R, and the receptor for advanced glycation end products (RAGE) in diabetic and TP-DM mice. Capsaicin also regulated epithelial-mesenchymal transition (EMT) and modulated the expression of fibrosis-related proteins, including E-cadherin, N-cadherin, vimentin, fibronectin, α-SMA, TGFBR2, TGF-β1, and p-Smad in TP-DM mice. In this study, capsaicin alleviated diabetic prostate growth by attenuating EMT. Mechanistically, capsaicin affected EMT by regulating RAGE/IGF-1/AKT, AR, and TGF-β/Smad signalling pathways. These results provide with new therapeutic approach for treating T2DM or T2DM-induced prostate growth.

Skeletal muscle myosin heavy chain expression and 3D capillary network changes in streptozotocin-induced diabetic female mice.

It is not well-understood how type 1 diabetes (T1DM) affects skeletal muscle histological phenotype, particularly capillarisation. This study aimed to analyze skeletal muscle myosin heavy chain (MyHC) fibre type changes and 3D capillary network characteristics in experimental T1DM mice. Female C57BL/6J-OlaHsd mice were categorized into streptozotocin (STZ)-induced diabetic (n = 12) and age-matched non-diabetic controls (n =12). The muscle fibre phenotype of the soleus, gluteus maximus, and gastrocnemius muscles were characterized based on the expression of MyHC isoforms, while capillaries of the gluteus maximus were assessed with immunofluorescence staining, confocal laser microscopy and 3D image analysis. STZ-induced diabetic mice exhibited elevated glucose levels, reduced body weight, and prolonged thermal latency, verifying the T1DM phenotype. In both T1DM and non-diabetic mice, the gluteus maximus and gastrocnemius muscles predominantly expressed fast-twitch type 2b fibers, with no significant differences noted. However, the soleus muscle in non-diabetic mice had a greater proportion of type 2a fibers and comparable type 1 fiber densities (26.2 ± 14.6% vs 21.9 ± 13.5%) relative to diabetic mice. T1DM mice showed reduced fiber diameters (P = 0.026), and the 3D capillary network analysis indicated a higher capillary length per muscle volume in the gluteus maximus of diabetic mice compared to controls (P < 0.05). Overall, T1DM induced significant changes in the skeletal muscle, including shifts in MyHC fibre types, decreased fibre diameters, and increased relative capillarisation, possibly due to muscle fibre atrophy. Our findings emphasize the superior detail provided by the 3D analytical method for characterizing skeletal muscle capillary architecture, highlighting caution in interpreting 2D data for capillary changes in T1DM.

VDR restores the expression of PINK1 and BNIP3 in TECs of streptozotocin-induced diabetic mice.

Defective mitophagy in renal tubular epithelial cells is one of the main drivers of renal fibrosis in diabetic kidney disease. Our gene sequencing data showed the expression of PINK1 and BNIP3, two key molecules of mitophagy, was decreased in renal tissues of VDR-knockout mice. Herein, streptozotocin (STZ) was used to induce renal interstitial fibrosis in mice. VDR deficiency exacerbated STZ-induced renal impairment and defective mitophagy. Paricalcitol (pari, a VDR agonist) and the tubular epithelial cell-specific overexpression of VDR restored the expression of PINK1 and BNIP3 in the renal cortex and attenuated STZ-induced kidney fibrosis and mitochondrial dysfunction. In HK-2 cells under high glucose conditions, an increased level of α-SMA, COL1, and FN and a decreased expression of PINK1 and BNIP3 with severe mitochondrial damage were observed, and these alterations could be largely reversed by pari treatment. ChIP-qPCR and luciferase reporter assays showed VDR could positively regulate the transcription of Pink1 and Bnip3 genes. These findings reveal that VDR could restore mitophagy defects and attenuate STZ-induced fibrosis in diabetic mice through regulation of PINK1 and BNIP3.

Hypoglycemic effect and the mechanism of action of a polysaccharide from sweet corncob in a high-fat diet and streptozotocin-induced diabetic mice

Type 2 diabetes mellitus (T2DM) is a metabolic disease caused by a glycolipid metabolism disorder and islet β-cell dysfunction. SCP-80-I is a biologically active water-soluble polysaccharide isolated from sweet corncob, an agricultural byproduct. The hypoglycemic effects of SCP-80-I on T2DM mice and its mechanisms were investigated in this study. SCP-80-I was found to significantly reduce blood glucose and lipid deposition levels in T2DM mice, as well as decrease serum leptin and increase adiponectin secretion. Interestingly, real time-polymerase chain reaction (RT-PCR) and Western blotting results revealed that SCP-80-I could regulate the expression of several glycolipid metabolisms and insulin secretion genes and proteins, including 5'-AMP-activated protein kinase (AMPK), carnitine palmitoyltransferase I (CPT1), and acetyl coenzyme A carboxylase (ACC) in the liver and AMPK, sirtuin 1 (Sirt1), peroxisome proliferator-activated receptorycoactivator-1 (PGC-1α), and uncoupling protein 2 (UCP2) in the pancreas. To have a hypoglycemic effect, SCP-80-I regulated glycolipid metabolism and islet cell function in the liver by regulating the AMPK/ACC/CPT1 signaling pathway and the AMPK/Sirt1/PGC-1α and AMPK/Sirt1/UCP2 signaling pathways. These findings improve our understanding of polysaccharides derived from sweet corncob and the use of SCP-80-I in the production of hypoglycemic foods.

Microalgal Macular Pigment Alleviated the Pathogenic Process in the Streptozotocin-induced Diabetic ApoE-deficient Mice

Type 2 diabetes mellitus (T2DM) is one of the fastest growing epidemics in human history and characteristic is insulin resistance (IR), and endocrine disorder that promoted to decline in insulin production and inhibit cellular effects. Patients with T2DM would lead to many complications such as diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, diabetic foot, atherosclerosis, vascular inflammation, and hepatogenous diabetes due to hyperglycemia. Even after using medical treatment and lifestyle modifications, it is still hard to achieve the goal of reducing blood glucose to an optimal level. Microalga Chlorella sp., a unicellular green alga that has been used as a health food and nutritional product in the last few decades. Macular pigment (MP) produced by Chlorella sp. consists of rich lutein and zeaxanthin, which are regarded as the antioxidants to hyperglycemia-induced oxidative stress. MP is widely used in eye health care, however, few studies focused on scientifically exploring the protection mechanism of MP on diabetes mellitus. Therefore, this study aimed to explore MP extracted from Chlorella on reducing retinopathy and atherosclerosis damages in the diabetic apolipoprotein E deficient mice (ApoE−/−) with high-fat diet feeding and streptozotocin treatment. The results show that MP supplement could significantly reduce glucose tolerance, IR, inflammatory cytokines TNF-α and IL-6 levels, and the serum level of disease markers, i.e., triglyceride (TG), total cholesterol (TCHO), glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), total protein (TP), albumin (ALB), and blood urea nitrogen (BUN) in the diabetic ApoE−/− mice. In addition, the expression levels of cellular antioxidant enzymes were significantly increased and the adhesion factors as well as MAPK pathway proteins in renal tissues were significantly reduced after MP supplementation. The pathological changes of pancreatic islet morphology, hepatic lipid accumulation, outer nuclear layer and aortic plaque of the diabetic ApoE−/− mice were significantly alleviated by MP supplement. At present, most MP products are derived from marigold, Calendula offcinalis, in the market. However, microalgae cultivation includes the advantages on no seasonal limit, no competition, high yield and carbon reduction compared with other plants. In summary, the microalgal MP improved IR, ameliorated atherosclerosis, and alleviated retinopathy in the diabetic ApoE−/− mice. Consequently, the microalgal MP is potentially to be a healthy food ingredient for the biological effcacy of scavenging free radicals and stabilizing blood glucose. This work was supported by the grants of NSTC 110-2312-B-A49-001-MY3, NSTC 112-2811-B-A49 -501, NSTC 112-2811-B-A49 -503, NSTC 112-2321-B-A49 -018 and NSTC 112-2321-B-A49-005, from the National Science and Technology Council (NSTC), Taiwan. This work was also financially supported by the “Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B)” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project of the National Yang Ming Chiao Tung University and Ministry of Education (MOE), Taiwan. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Knockdown of thioredoxin interacting protein in Müller cells attenuates photoreceptor apoptosis in streptozotocin-induced diabetic mouse model

We explored the effect of inhibition of thioredoxin interacting protein (Txnip) on neuroprotection in Müller cells under high glucose. Wild-type (WT) and Txnip knockout (Txnip−/−) mice were used to establish a streptozotocin (STZ)-induced diabetes model and a Müller cells high glucose model. We detected BDNF expression and PI3K/AKT/CREB pathway activation levels in the retina and Müller cells of each group in vivo and in vitro experiments. The Txnip−/− STZ group showed higher expression of BDNF and phosphorylation of PI3K/AKT/CREB in retina, and less retinal photoreceptor apoptosis was observed in Txnip−/− diabetic group than in WT. After using an inhibitor of PI3K signaling pathway, BDNF expression was reduced; In vitro co-cultured with Müller cells in different groups, 661 W cells showed different situations, Txnip−/− Müller cells maximum downregulated Cleaved-caspase 3 expression in 661 W, accompanied by an increase in Bcl-2/Bax ratio. These findings indicate that inhibiting endogenous Txnip in mouse Müller cells can promote their expression and secretion of BDNF, thereby reducing HG induced photoreceptor apoptosis and having important neuroprotective effects on DR. The regulation of BDNF expression by Txnip may be achieved by activating the PI3K/AKT/CREB pathway. This study suggests that regulating Txnip may be a potential target for DR treatment.

N-acetylcysteine Protects Against Myocardial Ischemia–Reperfusion Injury Through Anti-ferroptosis in Type 1 Diabetic Mice

The hearts of subjects with diabetes are vulnerable to ischemia–reperfusion injury (IRI). In contrast, experimentally rodent hearts have been shown to be more resistant to IRI at the very early stages of diabetes induction than the heart of the non-diabetic control mice, and the mechanism is largely unclear. Ferroptosis has recently been shown to play an important role in myocardial IRI including that in diabetes, while the specific mechanisms are still unclear. Non-diabetic control (NC) and streptozotocin-induced diabetic (DM) mice were treated with the antioxidant N-acetylcysteine (NAC) in drinking water for 4 week starting at 1 week after diabetes induction. Mice were subjected to myocardial IRI induced by occluding the coronary artery for 30 min followed by 2 h of reperfusion, subsequently at 1, 2, and 5 week of diabetes induction. The post-ischemic myocardial infarct size in the DM mice was smaller than that in NC mice at 1 week of diabetes but greater than that in the NC mice at 2 and 5 week of diabetes, which were associated with a significant increase of ferroptosis at 2 and 5 week but a significant reduction of ferroptosis at 1 week of diabetes. NAC significantly attenuated post-ischemic ferroptosis as well as oxidative stress and reduced infarct size at 2 and 5 week of diabetes. Application of erastin, a ferroptosis inducer, reversed the cardioprotective effects of NAC. It is concluded that increased oxidative stress and ferroptosis are the major factors attributable to the increased vulnerability to myocardial IRI in diabetes and that attenuation of ferroptosis represents a major mechanism whereby NAC confers cardioprotection against myocardial IRI in diabetes.

The Early Pathogenesis of Diabetic Retinopathy and Its Attenuation by Sodium-Glucose Transporter 2 Inhibitors.

The early pathogenetic mechanism of diabetic retinopathy (DR) and its treatment remain unclear. Therefore, we investigated the early pathogenic alterations in DR using streptozotocin-induced diabetic mice and the protective effect of sodium-glucose cotransporter 2 (SGLT2) inhibitors against these alterations. Retinal vascular leakage was assessed by dextran fluorescence angiography. Retinal thickness and vascular leakage were increased 2 and 4 weeks after onset of diabetes, respectively. Immunostaining showed that morphological change of microglia (amoeboid form) was observed at 2 weeks. Subsequently, increased angiopoietin-2 expression, simultaneous loss of pericytes and endothelial cells, decreased vessel density, retinal hypoxia, and increased vascular endothelial growth factor (VEGF)-A/VEGF receptor system occurred at 4 weeks. SGLT2 inhibitors (luseogliflozin and ipragliflozin) had a significant protective effect on retinal vascular leakage and retinal thickness at a low dose that did not show glucose-lowering effects. Furthermore, both inhibitors at this dose attenuated microglia morphological changes and these early pathogenic alterations in DR. In vitro study, both inhibitors attenuated the lipopolysaccharide-induced activation of primary microglia, along with morphological changes toward an inactive form, suggesting the direct inhibitory effect of SGLT2 inhibitors on microglia. In summary, SGLT2i may directly prevent early pathogenic mechanisms, thereby potentially playing a role in preventing DR.

CPT1A Protects Podocytes From Lipotoxicity and Apoptosis InVitro and Alleviates Diabetic Nephropathy InVivo.

Defective fatty acid oxidation (FAO) has been implicated in diabetic kidney disease (DKD), yet little is known about the role of carnitine palmitoyltransferase-1A (CPT1A), a pivotal rate-limiting enzyme of FAO, in the progression of DKD. Here, we investigate whether CPT1A is a reliable therapeutic target for DKD. We first confirmed the downregulation expression of CPT1A in glomeruli from diabetic patients. We further evaluated the function of CPT1A in diabetic models. Overexpression of CPT1A exhibited protective effects in diabetic conditions, improving albuminuria and glomerular sclerosis, as well as mitigating glomerular lipid deposits and podocyte injury in streptozotocin-induced diabetic mice. Mechanistically, CPT1A not only fostered lipid consumption via fatty acid metabolism pathways, thereby reducing lipotoxicity, but also anchored Bcl2 to the mitochondrial membrane, thence preventing cytochrome C release and inhibiting the mitochondrial apoptotic process. Furthermore, a novel transcription factor of CPT1A, FOXA1, was identified. We elucidate the crucial role of CPT1A in mitigating podocyte injury and the progression of DKD, indicating that targeting CPT1A may be a promising avenue for DKD treatment.

Dosing time-dependent difference in the suppressive effect of empagliflozin on the development of mechanical pain hypersensitivity in diabetic mice.

A problem for patients with diabetes is the rise of complications, such as peripheral neuropathy, nephropathy and retinopathy. Among them, peripheral neuropathy, characterized by numbness and/or hypersensitivity to pain in the extremities, is likely to develop in the early stages of diabetes. Empagliflozin (EMPA), a sodium-glucose cotransporter-2 inhibitor, exerts hypoglycemic effects by preventing glucose reabsorption in proximal tubular cells. EMPA can improve cardiovascular and renal outcomes in diabetic patients, but its suppressive effect on the development of diabetic neuropathy remains unclear. In this study, we demonstrated that optimizing the dosing schedule of EMPA suppressed the development of pain hypersensitivity in streptozotocin (STZ)-induced diabetic model mice maintained under standardized light/dark cycle conditions. A single intraperitoneal administration of STZ to mice induced hyperglycemia accompanied by pain hypersensitivity. Although EMPA did not exert anti-hypersensitivity effect on STZ-induced diabetic mice after the establishment of neuropathic pain, the development of pain hypersensitivity in the diabetic mice was significantly suppressed by daily oral administration of EMPA at the beginning of the dark phase. On the other hand, the suppressive effect was not observed when EMPA was administered at the beginning of the light phase. The hypoglycemic effect of EMPA and its stimulatory effect on urinary glucose excretion were also enhanced by the administration of the drug at the beginning of the dark phase. Nocturnal mice consumed their food mainly during the dark phase. Our results support the notion that morning administration of EMPA may be effective in suppressing the development of peripheral neuropathy in diabetic patients. Significance Statement Empagliflozin, a sodium-glucose cotransporter-2 inhibitor suppressed the development of neuropathic pain hypersensitivity in streptozotocin-induced diabetic model mice in a dosing time-dependent manner.

Design and Self-Assembly of Peptide-Copolymer Conjugates into Nanoparticle Hydrogel for Wound Healing in Diabetes.

Delayed wound healing in skin injuries has become a significant problem in clinics, seriously affecting and even threatening life and health. Recently, research interest has increased in developing wound dressings containing bioactive compounds capable of improving outcomes for complex healing needs. In this study, Puerarin-loaded nanoparticles (Pue-NPs) were prepared using the cell-penetrating peptide-poly (lactic-co-glycolic acid) (CPP-PLGA) as a drug carrier by the emulsified solvent evaporation method. Then, they were added into poly (acrylic acid) to obtain a self-assembled nanocomposite hydrogels (SANHs) drug delivery system using the co-polymerization method. The particle size, zeta potential, and micromorphology of Pue-NPs were measured; the appearance, mechanical properties, adhesive strength, and biological activity of SANHs were performed. Finally, the potential of SANHs for wound healing was further evaluated in streptozotocin-induced diabetic mice. Pue-NPs were regularly spherical, with an average particle size of 134.57 ± 1.42 nm and a zeta potential of 2.14 ± 0.78 mV. SANHs was colorless and transparent with a honeycomb-like porous structure and had an excellent swelling ratio (917%), water vapor transmission rate (3077 g·m-2·day-1), mechanical properties (Young's modulus of 18 kPa, elongation at break of 307%), and adhesive strength (15.5 kPa). SANHs exhibited sustained release of Pue over 48h, with a cumulative release of 55.60 ± 6.01%. In vitro tests revealed that the SANHs presented a 92.22% antibacterial rate against Escherichia coli after 4h, and a 61.91% scavenging rate of 1.1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical. In vivo experiments showed that SANHs accelerated wound repair by reducing the inflammatory response at the wound site, promoting angiogenesis, and facilitating epidermal regeneration and collagen deposition. In conclusion, we successfully prepared SANHs. Our results show that SANHs have excellent performance and improves wound healing in diabetic mice model, indicating that it can be used to develop an effective strategy for the treatment of diabetic wounds.

Protective effect of lycorine hydrochloride against diabetic nephropathy in high-fat diet and streptozotocin-induced diabetic mice

Diabetic nephropathy (DN) poses a significant risk to individuals with diabetes. Inflammation plays a crucial role in DN pathogenesis. Lycorine hydrochloride (LH) is derived from Lycoris radiata (L'Hér.). This herb has been identified as a potent anti-inflammatory molecule. Further studies indicated that LH displayed therapeutic potential against metabolic disorders, renal dysfunction, and fibrosis in a high-fat diet and streptozotocin-induced (HFD/STZ)-induced DN mouse model. Mechanistically, LH mitigated renal inflammation in DN mice by targeting NF-κB pathways and the NLRP3 inflammasome verified by in vivo study. In vitro, LH inhibited NLRP3 inflammasome activation induced by nigericin (Ng), monosodium urate (MSU), and ATP, reduced caspase-1 activation, and IL-1β release. Additionally, LH suppressed the NF-κB IS-induced activation, prevented nuclear translocation of NF-κB, and subsequently reduced the expression of downstream proteins COX2 and iNOS. Collectively, these results indicated that LH primarily improved hyperglycemia-induced renal function by reducing inflammation by targeting NF-κB and NLRP3 inflammasome, implying it is a promising therapeutic agent for DN.

Synthesis of Silver Nanoparticles Using Camellia sinensis Leaf Extract: Promising Particles for the Treatment of Cancer and Diabetes.

Both diabetes and cancer pose significant threats to public health. To overcome these challenges, nanobiotechnology offers innovative solutions for the treatment of these diseases. However, the synthesis of nanoparticles can be complex, costly and environmentally toxic. Therefore, in this study, we successfully synthesized Camellia sinensis silver nanoparticles (CS-AgNPs) biologically from methanolic leaf extract of C. sinensis and as confirmed by the visual appearance which exhibited strong absorption at 456 nm in UV-visible spectroscopy. The fourier transform infrared spectroscopy (FTIR) analysis revealed that phytochemicals of C. sinensis were coated with AgNPs. Scanning electron microscopy (SEM) analysis showed the spherical shape of CS-AgNPs, with a size of 15.954 nm, while X-ray diffraction spectrometry (XRD) analysis detected a size of 20.32 nm. Thermogravimetric analysis (TGA) indicated the thermal stability of CS-AgNPs. The synthesized CS-AgNPs significantly inhibited the ehrlich ascites carcinoma (EAC) cell growth with 53.42±1.101 %. The EAC cell line induced mice exhibited increased level of the serum aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), however this elevated serum parameter significantly reduced and controlled by the treatment with CS-AgNPs. Moreover, in a streptozotocin-induced diabetic mice model, CS-AgNPs greatly reduced blood glucose, total cholesterol, triglyceride, low-density lipoprotein (LDL) and creatinine levels. These findings highlight that the synthesized CS-AgNPs have significant anticancer and antidiabetic activities that could be used as promising particles for the treatment of these major diseases. However, pre-clinical and clinical trial should be addressed before use this particles as therapeutics agents.

Two rare flavonoid glycosides from Litsea glutinosa (Lour.) C. B. Rob.: experimental and computational approaches endorse antidiabetic potentiality

BackgroundLitsea glutinosa (Lour.) C. B. Rob. belongs to the Litsea genus and is categorized under the family of Lauraceae. The study aimed to investigate the phytoconstituents and pharmacological properties of methanol extract of leaves of Litsea glutinosa, focusing on antidiabetic activity via in vivo and in silico techniques.MethodsExtensive chromatographic and spectroscopic techniques were applied to isolate and characterize the constituents from the L. glutinosa plant species. The antidiabetic activity was studied in streptozotocin-induced diabetes mice, and the computational study of the isolated compounds was carried out by utilizing AutoDock Vina programs. In addition, the pharmacokinetic properties in terms of absorption, distribution, metabolism and excretion (ADME) and toxicological profiles of the isolated compounds were examined via in silico techniques.ResultsIn the present study, two flavonoid glycosides 4΄-O-methyl (2 ̋,4 ̋-di-E-p-coumaroyl) afzelin (1) and quercetin 3-O-(2 ̋,4 ̋-di-E-p-coumaroyl)-α-L-rhamnopyranoside (2) were isolated from the leaves of L. glutinosa and characterized by 1H and 13C NMR, COSY, HSQC, HMBC, and mass spectral data. Although compounds 1 and 2 have been reported twice from Machilis litseifolia and Lindera akoensis, and Machilis litseifolia and Mammea longifolia, respectively, this is the first report of this isolation from a Litsea species. Administering the methanolic extract of L. glutinosa at doses of 300 and 500 mg/kg/day to mice with diabetes induced by streptozotocin led to a significant decrease in fasting blood glucose levels (p < 0.05) starting from the 7th day of treatment. Besides, the computational study and PASS analysis endorsed the current in vivo findings that the both isolated compounds exerted higher binding affinities to human pancreatic α-amylase and aldose reductase than the conventional drugs. The in silico ADMET analysis revealed that the both isolated compounds have a favorable pharmacokinetic and safety profile suitable for human consumption.ConclusionAccording to the current outcomes obtained from in vivo and in silico techniques, the leaf extract of L. glutinosa could be a natural remedy for treating diabetes, and the isolated phytoconstituents could be applied against various illnesses, mainly hyperglycemia. However, more investigations are required for extensive phytochemical isolation and pharmacological activities of these phytoconstituents against broader targets with exact mechanisms of action.