Streptozocin-induced Diabetes Research Articles

The Effect of Cerium Oxide (CeO2) on Ischemia-Reperfusion Injury in Skeletal Muscle in Mice with Streptozocin-Induced Diabetes.

Objective: Lower extremity ischemia-reperfusion injury (IRI) may occur with trauma-related vascular injury and various vascular diseases, during the use of a tourniquet, in temporary clamping of the aorta in aortic surgery, or following acute or bilateral acute femoral artery occlusion. Mitochondrial dysfunction and increased basal oxidative stress in diabetes may cause an increase in the effects of increased reactive oxygen species (ROS) and mitochondrial dysfunction due to IRI. It is of great importance to examine therapeutic approaches that can minimize the effects of IRI, especially for patient groups under chronic oxidative stress such as DM. Cerium oxide (CeO2) nanoparticles mimic antioxidant enzymes and act as a catalyst that scavenges ROS. In this study, it was aimed to investigate whether CeO2 has protective effects on skeletal muscles in lower extremity IRI in mice with streptozocin-induced diabetes. Methods: A total of 38 Swiss albino mice were divided into six groups as follows: control group (group C, n = 6), diabetes group (group D, n = 8), diabetes-CeO2 (group DCO, n = 8), diabetes-ischemia/reperfusion (group DIR, n = 8), and diabetes-ischemia/reperfusion-CeO2 (group DIRCO, n = 8). The DCO and DIRCO groups were given doses of CeO2 of 0.5 mg/kg intraperitoneally 30 min before the IR procedure. A 120 min ischemia-120 min reperfusion period with 100% O2 was performed. At the end of the reperfusion period, muscle tissues were removed for histopathological and biochemical examinations. Results: Total antioxidant status (TAS) levels were found to be significantly lower in group DIR compared with group D (p = 0.047 and p = 0.022, respectively). In group DIRCO, total oxidant status (TOS) levels were found to be significantly higher than in group DIR (p < 0.001). The oxidative stress index (OSI) was found to be significantly lower in group DIR compared with group DCO (p < 0.001). Paraoxanase (PON) enzyme activity was found to be significantly increased in group DIR compared with group DCO (p < 0.001). The disorganization and degeneration score for muscle cells, inflammatory cell infiltration score, and total injury score in group DIRCO were found to be significantly lower than in group DIR (p = 0.002, p = 0.034, and p = 0.001, respectively). Conclusions: Our results confirm that CeO2, with its antioxidative properties, reduces skeletal muscle damage in lower extremity IRI in diabetic mice.

Glycemic homeostasis of ultrasound-assisted Murraya koenigii (Linn.) Spreng. bark extract in streptozocin-induced diabetes in rats

AbstractNumerous diseases have been linked to oxidative stress, emphasizing its role in pathogenicity. This study employed an ultrasound-assisted extraction process to obtain extracts from the bark of Murraya koenigii (L) Spreng. A thorough analysis was conducted on these dry extracts to determine their total phenolic and flavonoid content across four solvent fractions: n-hexane, ethyl acetate, n-butanol, and aqueous. Among the solvent fractions, ethyl acetate and n-butanol showed higher levels of total flavonoid content (TFC) and total phenolic content (TPC) compared to the others. The ethyl acetate fraction displayed the highest TPC (58.27 ± 4.20 mg GAE/g) and TFC (878.67 ± 40.38 mg QE/g) at 250 µg/mL concentration. Furthermore, the in-vitro antioxidant capacity of the ethyl acetate fraction was assessed for its ability to scavenge DPPH and hydrogen peroxide, revealing a concentration-dependent effect with IC50 values of 154.6 ± 6.2 and 55.12 ± 4.28 μg/mL, respectively. In a controlled experiment using streptozocin-induced diabetic rats, administering UMBE-EA at doses of 100 and 200 mg/kg notably improved blood glucose levels and body weight. Furthermore, several biochemical indicators, such as total protein levels, serum insulin, and the activities of enzymes like SGOT, SGPT, and ALP, as well as liver glycogen, showed significant enhancements. The antioxidant enzyme activities, including SOD, CAT, and GSH, returned to more favorable levels, and TABAR levels were normalized. In conclusion, the findings from this study strongly suggest that UMBE-EA possesses substantial anti-diabetic efficacy in Wistar rats, primarily attributed to its remarkable antioxidant properties and capacity to scavenge free radicals. These results provide valuable insights into the potential therapeutic benefits of UMBE-EA in diabetes management.

Effects of sevoflurane and fullerenol C60 on lower limb ischemia-reperfusion injury in streptozocin-induced diabetic mice.

Ischemia-reperfusion injury (IRI) poses a significant challenge for physicians, necessitating the management of cell damage and the preservation of organ functions. Various surgical procedures, such as vascular surgery on extremities, temporary cross-clamping of the abdominal aorta in aortic surgery, and the use of a tourniquet in extremity surgeries, may induce lower limb IRI. The susceptibility to IRI is heightened in individuals with diabetes. This study aimed to investigate the effects of fullerenol C60 and sevoflurane on mouse muscle tissue in a lower limb IRI model and to assess their potential in preventing complications arising from ischemia-reperfusion in mice with streptozocin-induced diabetes. A total of 36 adult Swiss albino mice were randomly divided into six groups, each consisting of six mice: control group (group C), diabetes group (group D), diabetes-ischemia/reperfusion group (group DIR), diabetes-ischemia/reperfusion-fullerenol C60 group (group DIR-FC60), diabetes-ischemia/reperfusion-sevoflurane group (group DIR-S), and diabetes-ischemia/reperfusion-sevoflurane-fullerenol C60 group (DIR-S-FC60). Streptozocin (55 mg/kg) was intraperitoneally administered to induce diabetes in the relevant groups, with mice displaying blood glucose levels of 250 mg/dL or higher at 72 h were considered diabetic. After 4 weeks, all groups underwent laparotomy under anesthesia. In DIR-FC60 and DIR-S-FC60 groups, fullerenol C60 (100 mg/kg) was intraperitoneally administrated 30 min before the ischemia period. Sevoflurane, delivered in 100% oxygen at a rate of 2.3% and 4 L/min, was administered during the ischemia period in DIR-S and DIR-S-FC60 groups. In the IR groups, a microvascular clamp was placed on the infrarenal abdominal aorta for 120 min during the ischemia period, followed by the removal of the clamp and a 120-min reperfusion period. At the end of the reperfusion, gastrocnemius muscle tissues were removed for histopathological and biochemical parameter examinations. Histopathological examination revealed a significant reduction in the disorganization and degeneration of muscle cells in the DIR-S-FC60 group compared to the DIR group (p = 0.041). Inflammatory cell infiltration was notably lower in the DIR-S, DIR-FC60, and DIR-S-FC60 groups than in the DIR group (p = 0.031, p = 0.011, and p = 0.013, respectively). The total damage scores in the DIR-FC60 and DIR-S-FC60 groups were significantly lower than in the DIR group (p = 0.018 and p = 0.008, respectively). Furthermore, the levels of malondialdehyde (MDA) in the DIR-S, DIR-FC60, and DIR-S-FC60 groups were significantly lower than in the DIR group (p < 0.001, p < 0.001, and p < 0.001, respectively). Catalase (CAT) enzyme activity in the DIR-S, DIR-FC60, and DIR-S-FC60 groups was higher than in the DIR group (p = 0.001, p = 0.014, and p < 0.001, respectively). Superoxide dismutase (SOD) enzyme activity in the DIR-FC60 and DIR-S-FC60 groups was also higher than in the DIR group (p < 0.001 and p = 0.001, respectively). Our findings indicate that administering fullerenol C60 30 min prior to ischemia in diabetic mice, in combination with sevoflurane, led to a reduction in oxidative stress and the correction of IR-related damage in muscle tissue histopathology. We believe that the administration of fullerenol C60 before IR, coupled with sevoflurane administration during IR, exerts a protective effect in mice.

Hypoglycemic and Hepatoprotective Activities of Coriander (Coriandrum sativum) Extract in Streptozocin Induced Diabetic Rats

The present study was designed to evaluate the role of Coriander (Coriandrum sativum) for management of diabetes instead of manufactured drugs, which led to many complications. Medicinal plants would be higher useful for this purpose because they are considered to be effective and non-toxic and safer than manufactured drugs. Aqueous extract of Coriander (C. sativum) was used to measurements their antidiabetic and hepatoprotective effects in streptozocin (STZ) induced diabetic male albino rats. Coriander (C. sativum) was given to the STZ induced diabetic rats at the concentration of 200 mg/kg body weight in different groups of three diabetic rats each orally once a day for 15 days. Body weight showed significant increase after 15 days of treatment with Coriander (C. sativum) extract compared with the normal control rats group (N). Blood glucose level on 15th day of treatment became significantly lower. The extract induced significant reduction in serum glucose, total lipids, total cholesterol, triglycerides level and transaminases (AST, ALT and γ-GT) activities. Liver glycogen content was significantly increased in treated animals compared to control group (N). The present data revealed insignificant changes in the serum total protein, albumin and globulin level during the experimental period. The lipid peroxidation determined was found to be decreased in plasma, liver and kidney of streptozocin induced diabetic rats treated with Coriander (C. sativum) extract (STZ/T) and rats group given Coriander (C. sativum) extract and then induced streptozocin (T/STZ), compared to control streptozocin induced diabetic rats group (STZ©). Glutathione reductase (GSH-R), glutathione peroxidase (GSH-P) and superoxide dismutase (SOD) activities were increased in liver and kidney of rat groups. These findings demonstrates that Coriander (C. sativum) extract have antioxidant effect for reducing lipid peroxidation in plasma and tissues and improve the liver function and antioxidant enzymes in treated rat groups compared to diabetic control rat group (STZ©). These observations revealed that the use of Coriander (C. sativum) extract can be recommended as natural antidiabetic, antioxidant and hypolipidemic activity agent. Findings of the present study suggest that the aqueous extract of Coriander (C. sativum) at the dose of 200 mg/kg body weight brings about significant beneficial effects in various biochemical parameters during diabetic and these effects are quite comparable with standard drug used to treat diabetes mellitus.

The Effect of Sevoflurane and Fullerenol C 60 on the Liver and Kidney in Lower Extremity Ischemia-Reperfusion Injury in Mice with Streptozocin-Induced Diabetes.

This study aimed to demonstrate whether fullerenol C60, sevoflurane anesthesia, or a combination of both had protective effects on the liver and kidneys in lower extremity ischemia-reperfusion injury (IRI) in mice with streptozocin-induced diabetes. A total of 46 Swiss albino mice were divided into six groups as follows: control group (group C, n=7), diabetes group (group D, n=7), diabetes-ischemia/reperfusion (group DIR, n=8), diabetes-ischemia/reperfusion-fullerenol C60 (group DIR-FC60, n=8), diabetes-ischemia/reperfusion-sevoflurane (group DIR-S, n=8), and the diabetes-ischemia/reperfusion-fullerenol C60-sevoflurane (group DIR-S-FC60, n=8). Fullerenol C60 (100mg/kg) was administered intraperitoneally 30 min before the ischemia-reperfusion procedure to the fullerenol groups (DIR-FC60 and DIR-S-FC60). In the DIR groups, 2 hours (h) ischemia-2h reperfusion periods were performed. In the sevoflurane groups, sevoflurane was applied during the ischemia-reperfusion period with 100% O2. Liver and kidney tissues were removed at the end of the reperfusion procedure for biochemical and histopathological examinations. In liver tissue, hydropic degeneration, sinusoidal dilatation, pycnotic nuclei, prenecrotic cells, and mononuclear cell infiltration in parenchyma were significantly more frequent in group DIR than in groups D and group C. In terms of the histopathologic criteria examined, more positive results were seen in group DIR-FC60, and when group DIR-FC60 was compared with group DIR, the difference was significant. The best results in AST, ALT, glucose, TBARS levels, and SOD enzyme activities in liver tissue were in group DIR-FC60 compared with group DIR, followed by groups DIR-S-FC60 and DIR-S, respectively. Regarding TBARS levels and SOD enzyme activities in kidney tissue, the best results were in groups DIR-FC60, DIR-S-FC60, and DIR-S, respectively. According to our findings, it is clear that fullerenol C60 administered intraperitoneally 30 min before ischemia, alone or together with sevoflurane, reduces oxidative stress in distant organ damage caused by lower extremity IRI, and reduces liver and kidney tissue damage in histopathologic examinations.

Observation of the neuroprotective efficacy of vitamin K in a streptozocin-induced diabetes model in chick embryos.

Diabetes mellitus (DM)is a metabolic disease characterized by hyperglycemia due to insulin deficiency and/or resistance. Vitamin K (VK)is a group of fat-soluble molecules, including naturally occurring vitamin K1 (phylloquinone). vitamin K2 (menaquinone), and synthetic vitamin K3 (menadione). Beyond coagulation, the health benefits of VK have been described to play different roles in both physiological and pathological processes such as inflammation, energy metabolism, neuroprotection, cellular growth, and survival. It was aimed to observe the antioxidant and/or neuroprotective activity of vitamin K1 in our model of chick embryo diabetic neuropathy (DN)induced by streptozotocin (STZ). Ninety White Leghorn, fertile and 0-day-old SPF (specific pathogen-free) eggs (57 ± 4 gr) were used in the study. Chick embryo blood brain tissues were taken for biochemical evaluation. Plasma insulin and glucose levels were measured. In addition, brain tissue total antioxidant level (TAS),total oxidant level (TOS),malondialdehyde (MDA), and vascular endothelial growth factor (VEGF)levels were measured. Plasma glucose levels were higher in the STZ-treated groups and lower in the treatment groups. Plasma insulin levels were observed to be higher in STZ groups in groups treated with high VK. Low TAS, high MDA, TOS, and VEGF levels were recorded in brain tissue STZ groups. Low VEGF, TOS, and MDA levels were recorded in the group treated with the highest VK, while high TAS levels were observed. In our STZ-induced chick embryo diabetic neuropathy model, we observed that VK1 reduced oxidant damage by showing antioxidant properties or by modulating antioxidant enzymes.

THU123 Knockout Of Renal Glut2 Gene Activates The Hypothalamic-pituitary-adrenal Axis To Increase Glucose Production In Mice

Abstract Disclosure: T.S. Faniyan: None. J. Robles: None. X. Zhang: None. S. Bathina: None. P.S. Brookes: None. R.J. Perry: None. K.H. Chhabra: None. We recently reported the contribution of renal GLUT2 (glucose transporter 2) to systemic glucose homeostasis using a mouse model in which we can knockout renal Glut2 gene at a desired time. Renal Glut2 knockout mice have improved glucose tolerance and are protected from high-fat diet or streptozocin-induced diabetes because they excrete excess blood glucose in urine. Interestingly, despite the profound loss of glucose in urine, renal Glut2 knockout mice have normal fasting blood glucose levels. These findings indicate that an increase in endogenous glucose production may be compensating for the loss of glucose in urine. To determine the mechanisms responsible for evoking the increase in endogenous glucose production, we focused on studying the hypothalamic-pituitary-adrenal (HPA) axis because of its established role in elevating blood glucose levels. We used ELISA to measure circulating adrenocorticotrophic hormone (ACTH) and corticosterone, which are major hormones of the HPA axis. Moreover, we used fluorescence in situ hybridization to assess the expression of hypothalamic corticotropin releasing hormone gene (Crh). We also performed in vitro metabolomics analysis of the mouse liver using mass spectrometry. Finally, we measured glucose production from pyruvate in vivo in the liver and kidney using mass isotopomer distribution analysis. Renal Glut2 knockout mice had increased (p&amp;lt;0.05) levels of hypothalamic Crh (100 ±13 vs 142 ±9 %, control vs experimental), circulating ACTH (120 ±8 vs 213 ±12 pg/ml), and corticosterone (30.4 ±5.5 vs 115 ±15.2 ng/ml). In addition, we found that metabolites such as hepatic glucose-6-phosphate (19.2 ±1.5 vs 15 ±1 arbitrary unit, control vs experimental), glucose-1-phosphate (20 ±1.5 vs 15.5 ±1), and fructose-6-phosphate (16 ±1.2 vs 12.4 ±0.8) were decreased in renal Glut2 knockout mice. We further observed that glucose production was increased in both the liver (15.1 ±0.4 vs 18.4 ±0.5 mg/kg/min) and kidney (1.7 ±0.2 vs 2.6 ±0.3 mg/kg/min) in renal Glut2 knockout mice. Our results demonstrate that loss of renal Glut2 causes hyperactivation of the HPA axis coupled with decrease in hepatic glucose metabolism and increase in hepatic as well as renal glucose production. These findings may explain how the renal Glut2 knockout mice prevent hypoglycemia despite massive glycosuria. Altogether, our study identifies a novel crosstalk between the kidneys, hypothalamus, and adrenal glands to regulate systemic glucose homeostasis. This information may be useful in either optimizing the efficacy of drugs that enhance glycosuria to treat diabetes or addressing the side effects of such drugs on the HPA axis. Presentation: Thursday, June 15, 2023

The effect of Metformin on salivary glands of rats with streptozocin-induced diabetes

The effect of Metformin on salivary glands of rats with streptozocin-induced diabetes

Impact of Disease States on the Oral Pharmacokinetics of EIDD-1931 (an Active Form of Molnupiravir) in Rats for Implication in the Dose Adjustment.

The pharmacokinetic alteration of an antimicrobial medication leading to sub-therapeutic plasma level can aid in the emergence of resistance, a global threat nowadays. In this context, molnupiravir (prodrug of EIDD-1931) is the most efficacious orally against corona virus disease (COVID-19). In addition to drug-drug interaction, the pharmacokinetics of a drug can significantly vary during any disease state, leading to disease-drug interaction. However, no information is available for such a recently approved drug. Therefore, we aimed to explore the oral pharmacokinetics of EIDD-1931 in seven chemically induced disease states individually compared to the normal state using various rat models. Induction of any disease situation was confirmed by the disease specific study(s) prior to pharmacokinetic investigations. Compared to the normal state, substantially lowered plasma exposure (0.47- and 0.63-fold) with notably enhanced clearance (2.00- and 1.56-fold) of EIDD-1931 was observed in rats of ethanol-induced gastric injury and carbon tetrachloride-induced liver injury states. Conversely, paclitaxel-induced neuropathic pain and cisplatin-induced kidney injury states exhibited opposite outcomes on oral exposure (1.43- and 1.50-fold) and clearance (0.69- and 0.65-fold) of EIDD-1931. Although the highest plasma concentration (2.26-fold) markedly augmented in the doxorubicin-induced cardiac injury state, streptozocin-induced diabetes and lipopolysaccharide-induced lung injury state did not substantially influence the pharmacokinetics of EIDD-1931. Exploring the possible phenomenon behind the reduced or boosted plasma exposure of EIDD-1931, results suggest the need for dose adjustment in respective diseased conditions in order to achieve desired efficacy during oral therapy of EIDD-1931.

The antidiabetic effect of methanolic extract of Holarrhena pubescens seeds is mediated through multiple mechanisms of action

Holarrhena pubescens is widely used in Indian and Chinese medicine in the treatment of diabetes. The current work determined the oral hypoglycemic and antidiabetic effects of seed extract in rats. The probable mechanism of action was evaluated in-vitro by α - glucosidase inhibition, glucose metabolism in insulinoma (INS-1) cells to reflect secretion of insulin, and protein glycation inhibition. Its potential for herb-drug interaction was evaluated in the cytochrome P450 3A4 (CYP3A4) inhibition assay. The seed extract increased serum insulin levels and reduced serum blood glucose levels in the oral glucose tolerance test. It also reduced the serum glucose levels in streptozocin-induced diabetes. The extract also inhibited α –glucosidase enzyme activity and demonstrated that it can increase the secretion of insulin from INS to 1-rat insulinoma cell line cells in-vitro in a concentration-dependent manner. However, it had a very weak inhibitory effect on protein glycation and it did not affect the activity of CYP3A4. The results of the study showed that H. pubescens seed extract increases insulin secretion and inhibits glucose absorption both in-vivo and in-vitro with a weak protein glycation inhibitory effect. The herb is devoid of CYP3A4 inhibitory effect indicating that it may not have pharmacokinetic interaction with the drug metabolized by this enzyme.

Wound Healing Activity of the Flavonoid-Enriched Fraction of Selaginella bryopteris Linn. against Streptozocin-Induced Diabetes in Rats

Diabetes and its complications, such as delayed wound healing, are increasing at an alarming rate in India, putting an enormous strain on the country’s limited healthcare resources. Hence, the present study proposes to screen/identify the possible mechanisms and to study the effect of the flavonoid-enriched fraction of Selaginella bryopteris extract against human keratinocyte cell lines (HaCaT) and streptozocin (STZ)-induced diabetic wounds in a male Wistar rat model. Chemical profiling was performed by an MTT assay. The obtained GC–MS analysis results showed the presence of amentoflavone, gallic acid, imidazole, palmitic acid, catechine, L-fucitol, lupeol, and myo-inositol as the major bioactive phytoconstituents. S. bryopteris induces the generation of ROS, the condensation of chromatin in the nucleus, and changes in the membrane potential of mitochondria in HaCaT cell lines. An S. bryopteris-dependent induction of apoptosis-mediated cell death in HaCaT cell lines was confirmed by an AO/PI analysis. Mitochondrial depolarization was reflected in JC-1 staining of cells. The wound size was reduced and epithelialization was enhanced. Keratinocyte migration decreased interleukins, TNF-α, IL-2, and IL-6 and the expression of pro-apoptotic (p53, caspase-3, caspase-9, and Bax) and anti-apoptotic (Bcl-2) genes in a dose-dependent manner. Keratinocyte migration increased antioxidant enzyme levels (CAT, SOD, MDA, and GSH). Wound healing is facilitated through the mitochondria-mediated apoptosis pathway, revealing a new area of diabetic wound therapy.

Antidiabetic and Toxicological Effects of the Tea Infusion of Summer Collection from Annona cherimola Miller Leaves

Annona cherimola Miller (Ac) is a plant used in Mexican traditional medicine for the treatment of diabetes. In this work, the tea infusion extracts obtained from 1.5 g of leaf powder from Ac collected in May (AcMa), June (AcJun), July (AcJul), and August (AcAu) were evaluated on streptozocin-induced diabetic (STID) mice and for subchronic toxicity in STID and non-diabetic (ND) mice. In addition, extracts were subjected to high-performance liquid chromatography with diode array detection (HPLC-DAD). Results showed that the tea infusion extract of the sample collected in August (AcAu) exhibited the most significant antihyperglycemic activity during all acute assays. The analysis of the extracts (AcMa, AcJu, AcJul, and AcAu) by HPLC-DAD revealed that flavonoid glycosides, rutin, narcissin, and nicotiflorin were the major components. In addition, the sample AcAu contained the best concentration of flavonoids. In the case of subchronic oral toxicity, the AcAu sample did not cause mortality in STID mice, and histopathological analysis revealed significant improvement in the changes associated with diabetes in the liver and kidneys. These findings suggest that the Ac leaves collected in August may be a source of flavonoids such as rutin, with antidiabetic potential. In addition, these findings support the use of Ac to treat diabetes in traditional medicine.

L-Lysine Ameliorates Diabetic Nephropathy in Rats with Streptozotocin-Induced Diabetes Mellitus.

Introduction Diabetic nephropathy is one of the leading causes of end-stage renal disease worldwide. Uncontrolled hyperglycemia and subsequent production of glycation end-products activate the paths which lead to diabetic nephropathy. The aim of this study was to assess the effects of L-lysine on antioxidant capacity, biochemical factors, kidney function, HSP70 level, and the expression of the TGFβ, VEGF, and RAGE genes in rats with streptozocin-induced diabetes mellitus. Methods Thirty-two male Wistar rats were randomly allocated to four eight-rat groups, namely, a healthy group, a diabetic group treated with vehicle (DM + vehicle), a diabetic group treated with L-lysine (DM + Lys), and a healthy group treated with L-lysine (healthy + Lys). Rats in the DM + Lys and the healthy + Lys groups were treated with L-lysine 0.15%. The levels of fasting blood glucose, insulin, HbA1C, advanced glycation end-products (AGEs), lipid profile, serum creatinine, blood urea nitrogen, glomerular filtration rate, urine microalbumin, oxidative stress parameters, kidney histology and morphology, and TGFβ, VEGF, and RAGE gene expressions were assessed. Findings. An eight-week treatment with L-lysine significantly reduced the levels of fasting blood glucose, AGEs, kidney function parameters, oxidative stress parameters, lipid profile, and the TGFβ, VEGF, and RAGE gene expression and significantly increased the levels of serum insulin and tissue HSP70. Conclusion Treatment with L-lysine seems to slow down the progression of diabetic nephropathy.

Lipid phosphate phosphatase‐3 dysfunction exaggerates neointimal hyperplasia following diabetic vascular injury

IntroductionDiabetes mellitus is a major risk factor for cardiovascular diseases and promotes neointimal hyperplasia characterized by occlusive disorders such as atherosclerosis and stenosis, caused by excessive proliferation and migration of vascular smooth muscle cells (VSMCs) following endovascular interventions such as balloon angioplasty and stent placement. Lipid phosphate phosphatase‐3 (LPP3) is an enzyme that regulates the availability of lysophosphatidic acid (LPA) and has been reported to play a significant role in vascular genesis, cellular permeability, tumor progression, vascular remodeling, and myocardial infarction. However, the functional role and mechanism of LPP3 in diabetic neointimal hyperplasia is unclear. LPP3 dysfunction may lead to LPA accumulation at the vascular injury site, leading to vascular inflammation, proliferation, and migration, causing restenosis. Recently, the Receptor for Advanced Glycation End product (RAGE) has been presented as a potential receptor for LPA leading to downstream signaling in vascular smooth muscle cells (VSMCs).MethodsIn this study, we used a streptozocin‐induced diabetes mice model. We made SM‐22 specific LPP3 knock‐out mice and performed endothelial denudation surgery in the carotid artery to induce neointima hyperplasia to tease out the role of LPP3 in restenosis. We isolated aortic VSMCs from LPP3 floxed and LPP3 knock‐out mice and cultured them under normal or high glucose media. The immunoblotting was performed and probed with antibodies for total extracellular signal‐regulated kinase (ERK) and phosphorylated‐ERK. The cell proliferation and migration assay was performed using the Electric Cell substrate Impedance Sensing (ECIS) with or without LPP3 in VSMC under normal or high glucose conditions. Data are mean ± SEM; P‐values were determined by Student t‐test or one‐way ANOVA with Tukey's post‐hoc tests.ResultWe observed a significant increase in proliferation (P&lt;0.01) and exaggerated migration (p&lt;0.01) of VSMC that lack LPP3 under the hyperglycemic condition in real‐time using ECIS. These effects are at least partially a consequence of decreased lysophosphatidic acid hydrolysis due to lack of LPP3 activity. Furthermore, VSMC that lack LPP3 showed increased phospho‐ERK expression (P&lt;0.01) under hyperglycemic conditions. The diabetic LPP3 knock‐out mice exhibited exaggerated neo‐intimal areas after the carotid injury compared to LPP3 floxed mice.ConclusionThese findings implicate that LPP3 plays a vital role as a negative regulator of smooth muscle phenotypic modulation. We speculate that changes in LPP3 expression control the development of neo‐intima by limiting smooth muscle cell proliferation, migration, and vascular inflammation in diabetic restenosis.

THE EFFECTS OF N-ACETYL-L-CYSTEINE ON OXIDATIVE PARAMETERS in TESTICULAR TISSUE OF STREPTOZOTOCIN INDUCED DIABETIC RATS

The protection of N-Acetyl-L-cysteine (NAC) was investigated in the streptozocin-induced diabetes model in rat testicular tissues. In vivo biochemical mechanism was determined by measuring antioxidant parameters. The rats were randomly divided into 4 groups such as control, diabetes, diabetes+NAC and NAC. A single dose of intraperitoneal streptozotocin (IP STZ) (60 mg / kg body weight) was given to animals fasted overnight. Before injection and 72 hours after injection, blood glucose levels were measured from the tail vein with a glucometer. The blood glucose levels above 250 mg / dL were considered diabetic. Animals in groups 3 and 4 did not receive any treatment for four weeks after the diabetes model was established. Four weeks later, subjects in Groups 3 and 4 were given an IP injection of NAC (60 mg / kg, prepared in 0.9% NaCl solution daily) for 7 days. At the end of the applications, all animals were sacrificed and tissues were taken for antioxidant measurements. While the malondialdehyde (MDA) level increased in STZ-induced diabetic rat’s testicular tissues, it was brought to the control level with NAC treatment. The glutathione (GSH) and nitric oxide (NOx) level, superoxide dismutaze (SOD) and caalase (CAT) enzyme activities were found significantly reduced in the diabetic group. However, NAC treatment resulted in elevated these parameters.

Glimepiride-Loaded Nanoemulgel; Development, In Vitro Characterization, Ex Vivo Permeation and In Vivo Antidiabetic Evaluation.

Glimepiride (GMP), an oral hypoglycemic agent is extensively employed in the treatment of type 2 diabetes. Transdermal delivery of GMP has been widely investigated as a promising alternative to an oral approach but the delivery of GMP is hindered owing to its low solubility and permeation. The present study was designed to formulate topical nanoemulgel GMP system and previously reported solubility enhanced glimepiride (GMP/βCD/GEL-44/16) in combination with anti-diabetic oil to enhance the hypoglycemic effect. Nanoemulsions were developed using clove oil, Tween-80, and PEG-400 and were gelled using xanthan gum (3%, w/w) to achieve the final nanoemulgel formulations. All of the formulations were evaluated in terms of particle size, zeta potential, pH, conductivity, viscosity, and in vitro skin permeation studies. In vivo hypoglycemic activity of the optimized nanoemulgel formulations was evaluated using a streptozocin-induced diabetes model. It was found that a synergistic combination of GMP with clove oil improved the overall drug permeation across the skin membrane and the hypoglycemic activity of GMP. The results showed that GMP/βCD/GEL-44/16-loaded nanoemulgel enhanced the in vitro skin permeation and improved the hypoglycemic activity in comparison with pure and marketed GMP. It is suggested that topical nano emulsion-based GMP gel and GMP/βCD/GEL-44/16 could be an effective alternative for oral therapy in the treatment of diabetes.

Supplementation with selenium nanoparticles alleviates diabetic nephropathy during pregnancy in the diabetic female rats.

The bioactivity of nanoparticles has engendered a promise in scientific communities for developing novel therapeutic strategies. This study investigated the protective effects of selenium nanoparticles (SeNPs) against kidney injury in streptozocin-induced diabetes during pregnant (DDP) rats. The female rats were separated into three groups (n = 8). Group 1 received the vehicle, normal saline. Group 2 received a single intraperitoneal dose of 50 mg/kg of streptozocin. Group 3 received a single intraperitoneal injection of 50 mg/kg of streptozocin, followed by treatment with SeNPs at a dose of 2.5 mg/kg twice a week for 6 weeks (1 week before gestation and continuing for 5 additional weeks). The structure formed by the fabricated SeNPs with citric acid in the presence of ascorbic acid indicated that nano-Se was associated with a carbon matrix. The diabetic group suffered from polyuria, a reduction in body weight, delayed gestation, and only 40% successful pregnancy compared with the control rats. Interestingly, SeNPs significantly reduced the rate of urination, accelerated the start of gestation, and increased the percentage of successful pregnancy in females with DM. Severe changes were observed in the pancreatic β-cells of the diabetic rats, with darkly stained and fragmented chromatin in nuclei, while SeNPs partially restored the normal morphological features of the pancreatic β-cells. The concentrations of urea, creatinine, MDA, and glucose were significantly increased in the diabetic rats, while GSH was significantly reduced compared with controls. Interestingly, SeNPs restored all of these parameters to values at or near control levels. SeNPs were capable of improving the histological structure of the kidney in mothers with DDP. Hence, the present work is relevant to GDM demonstrating SeNPs shielding the kidney structure and function in vivo.

Contributions of Sodium-Hydrogen Exchanger 1 and Mitogen-Activated Protein Kinases to Enhanced Retinal Venular Constriction to Endothelin-1 in Diabetes.

Diabetes elevates endothelin-1 (ET-1) in the vitreous and enhances constriction of retinal venules to this peptide. However, mechanisms contributing to ET-1-induced constriction of retinal venules are incompletely understood. We examined roles of sodium-hydrogen exchanger 1 (NHE1), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and extracellular calcium (Ca2+) in retinal venular constriction to ET-1 and the impact of diabetes on these signaling molecules. Retinal venules were isolated from control pigs and pigs with streptozocin-induced diabetes for in vitro studies. ET-1-induced vasoconstriction was abolished in the absence of extracellular Ca2+ and sensitive to c-Jun N-terminal kinase (JNK) inhibitor SP600125 but unaffected by extracellular signal-regulated kinase (ERK) inhibitor PD98059, p38 kinase inhibitor SB203580, or broad-spectrum PKC inhibitor Gö 6983. Diabetes (after 2 weeks) enhanced venular constriction to ET-1, which was insensitive to PD98059 and Gö 6983 but was prevented by NHE1 inhibitor cariporide, SB203580, and SP600125. In conclusion, extracellular Ca2+ entry and activation of JNK, independent of ERK and PKC, mediate constriction of retinal venules to ET-1. Diabetes activates p38 MAPK and NHE1, which cause enhanced venular constriction to ET-1. Treatments targeting these vascular molecules may lessen retinal complications in early diabetes.

Saxagliptin protects against diabetic nephropathy by inhibiting caspase 3/PARP-1-dependent nephrocyte apoptosis.

Saxagliptin (SAX) can protect against tissue damage caused by diabetic nephropathy. However, whether this compound can restore kidney function, and its specific mechanism of action remain unclear. The present study explored the therapeutic effects and mechanisms of SAX. Male Wistar rats (8 weeks old) were randomly divided into the following groups: A control group (n=10); a group with streptozocin-induced diabetes mellitus (DM) treated with saline (n=20); and a group with streptozocin-induced DM treated with SAX (n=20). Following 20 weeks of treatment, renal function and the extent of renal damage were assessed based on histological staining using hematoxylin and eosin, periodic acid-Schiff and Masson's trichrome staining. The experimental results indicated that Streptozocin induction of DM led to thicker basement membranes in mesangial cells and a more abundant extracellular matrix. These changes were ameliorated following treatment with SAX. The data demonstrated that renal tissue and renal cell apoptosis were ameliorated significantly following treatment with SAX. Furthermore, the expression levels of the apoptotic genes poly (ADP-ribose) polymerase-1 (PARP-1) and caspase 3 were significantly decreased following treatment with SAX. Therefore, SAX may reduce the extent of renal apoptosis and pathological outcomes in diabetic nephropathy by downregulating the expression of caspase 3 and PARP-1 in the death receptor pathway of apoptosis.

Diabetes Affects the Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP)-Like Immunoreactive Enteric Neurons in the Porcine Digestive Tract.

Diabetic gastroenteropathy is a common complication, which develops in patients with long-term diabetes. The pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide known for its cytoprotective properties and plays an important role in neuronal development, neuromodulation and neuroprotection. The present study was designed to elucidate, for the first time, the impact of prolonged hyperglycaemia conditions on a population of PACAP-like immunoreactive neurons in selected parts of the porcine gastrointestinal tract. The experiment was conducted on 10 juvenile female pigs assigned to two experimental groups: The DM group (pigs with streptozocin-induced diabetes) and the C group (control pigs). Diabetes conditions were induced by a single intravenous injection of streptozocin. Six weeks after the induction of diabetes, all animals were euthanised and further collected, and fixed fragments of the stomach, duodenum, jejunum, ileum and descending colon were processed using the routine double-labelling immunofluorescence technique. Streptozotocin-induced hyperglycaemia caused a significant increase in the population of PACAP-containing enteric neurons in the porcine stomach, small intestines and descending colon. The recorded changes may result from the direct toxic effect of hyperglycaemia on the ENS neurons, oxidative stress or inflammatory conditions accompanying hyperglycaemia and suggest that PACAP is involved in regulatory processes of the GIT function in the course of diabetes.