Streptozotocin Model Research Articles

Opioid and noradrenergic contributions of tapentadol to the inhibition of locus coeruleus neurons in the streptozotocin rat model of polyneuropathic pain

Tapentadol is an analgesic that acts as an agonist of µ opioid receptors (MOR) and that inhibits noradrenaline reuptake. Data from healthy rats show that tapentadol inhibits neuronal activity in the locus coeruleus (LC), a nucleus regulated by both the noradrenergic and opioid systems. Thus, we set out to investigate the effect of tapentadol on LC activity in streptozotocin (STZ)-induced diabetic rats, a model of diabetic polyneuropathy, by analyzing single-unit extracellular recordings of LC neurons. Four weeks after inducing diabetes, tapentadol dose-response curves were obtained from animals pre-treated with RX821002 or naloxone (alpha2-adrenoceptors and opioid receptors antagonists, respectively). In STZ rats, the spontaneous activity of LC neurons (0.9 ± 0.1 Hz) was lower than in naïve animals (1.5 ± 0.1 Hz), and tapentadol's inhibitory effect was also weaker. Alpha2-adrenoceptors blockade by RX821002 (100 μg/kg i.v.) in STZ animals significantly increased the spontaneous activity (from 0.8 ± 0.1 to 1.4 ± 0.2 Hz) and it dampened the inhibition of LC neurons produced by tapentadol. However, opioid receptors blockade following naloxone pre-treatment (5 mg/kg i.v.) did not alter the spontaneous firing rate (0.9 ± 0.2 vs 0.9 ± 0.2 Hz) or the inhibitory effect of tapentadol on LC neurons in STZ animals. Thus, diabetic polyneuropathy appears to exert neuroplastic changes in LC neurotransmission, enhancing the sensitivity of alpha2-adrenoceptors and dampening opioid receptors expression. Tapentadol's activity seems to be predominantly mediated through its noradrenergic effects rather than its influence on opioid receptors in the STZ model of diabetic polyneuropathy.

Pathogenesis of Type 1 Diabetes Mellitus and Rodent Experimental Models

The global prevalence of diabetes mellitus and its severe complications is on the rise. The study of the pathogenesis of the onset and the progression of complications related to the disease, as well as the search for new therapeutic agents and methods of treatment, remains relevant. Experimental models are extremely important in the study of diabetes. This survey contains a synthesis of the most commonly used experimental animal models described in scientific literature. The mechanisms of the streptozotocin model are also analyzed and discussed, as it is considered as the most adequate and easily reproducible diabetes model. A review of the significant advantages and disadvantages of the described models has also been conducted.

Cardiac effects of fish oil in a rat model of streptozotocin-induced diabetes

Background and aimsFish oil (FO) is rich in omega-3 polyunsaturated fatty acids, which have cardio-protective effects. This study aims to evaluate effects of FO in a rat model of streptozotocin (STZ) induced diabetes. Methods and resultsAdults male Wistar rats were assigned to control (4 μl corn oil/g corn oil given by oral gavage), FO (4 μl Menhaden FO/g body weight given by oral gavage), diabetes (DM, 35 mg/kg STZ single intraperitoneal injection, corn oil), and DM + FO groups for 8 weeks. Plasma and cardiac biomarkers of oxidative stress, inflammation, and fibrosis were evaluated. STZ-induced diabetes as indicated by the significant increase in serum levels of glucose and percentage of glycated hemoglobins. FO reduced plasma arachidonic acid (AA) percentage and ratio of AA: docosahexaenoic acid (DHA). Plasma and cardiac levels of total nitrite, endothelin -1 (ET-1), and myeloperoxidase (MPO) increased in the DM group, whereas cardiac activities of catalase and superoxide dismutase (SOD) decreased. FO reduced cardiac nitrite and MPO, and plasma ET-1 levels. FO increased cardiac glutathione, catalase and SOD activities. Levels of thiobarbituric acid substances increased in the FO and DM groups with significant synergism in the DM + FO group. FO prevented cardiac fibrosis associated with DM and decreased cardiac transforming growth factor beta-1and p38 MAP kinases. Cardiac levels of matrix metalloproteinase -2 were significantly elevated in FO and DM + FO groups. ConclusionsFO decreased plasma and cardiac oxidative stress, inflammation and myocardial fibrosis. FO could be used in diabetes to reduce risk and burden of CVDs.

Intraperitoneal Administration of Oxygen/Ozone to Rats Reduces the Pancreatic Damage Induced by Streptozotocin.

Background: The rat model of streptozotocin (STZ)-induced pancreatic damage was used to examine whether a systemic oxygen/ozone mixture could be beneficial for the pancreas by reducing the machinery of the local detrimental mediators released by STZ. Results: The results showed that oxygen/ozone administration (150 µg/Kg i.p.) for ten days in STZ rats increased the endogenous glutathione-s-transferase (GST) enzyme and nuclear factor-erythroid 2-related factor 2 (Nrf2) into the pancreatic tissue, together with reduction of 4-hydroxynonenal (4-HNE) and PARP-1 compared to STZ rats receiving O2 only. Interestingly, these changes resulted in higher levels of serum insulin and leptin, and pancreatic glucagon immunostaining. Consequently, glucose metabolism improved as evidenced by the monitoring of glycemia throughout. Conclusions: This study provides evidence that systemic administration of oxygen/ozone reduces the machinery of detrimental mediators released by STZ into the pancreas with less local damage and better functionality.

Synthesis, molecular modelling studies and ADME prediction of benzothiazole clubbed oxadiazole-Mannich bases, and evaluation of their anti-diabetic activity through in vivo model

A small library of new benzothiazole clubbed oxadiazole-Mannich bases (M-1 to M-22) were synthesized and characterized by IR, NMR, Mass and Elemental analysis results. Molecular docking studies were done to assess the binding mode and interactions of synthesized hits at binding site of receptor Peroxisome proliferator-activated receptor, PPAR-γ or PPARG (PDB 1FM9). Among the synthesized compounds, nine compounds were selected on the basis of docking score and evaluated for their in vivo anti-diabetic activity using Oral Glucose Tolerance Test (OGTT) in normal rats followed by Streptozotocin (STZ) - induced diabetes. Results indicated that compound M-14 (161.39 ± 4.38) showed the highest reduction of blood glucose level comparable to that of the standard drug glibenclamide (140.29 ± 1.24) in STZ model. Other compounds exhibited moderate to good anti hyperglycaemic activity. ADME studies was done using Molinspiration online software, revealed that all compounds (except M-11) are likely to be orally active as they obeyed Lipinski’s rule of five.

Evoked hypoalgesia is accompanied by tonic pain and immune cell infiltration in the dorsal root ganglia at late stages of diabetic neuropathy in mice.

Diabetic peripheral neuropathy is a major debilitating late complication of diabetes, which significantly reduces the quality of life in patients. Diabetic peripheral neuropathy is associated with a wide spectrum of sensory abnormalities, where in loss of sensation or hypoalgesia to applied external stimuli is paradoxically accompanied by debilitating tonic spontaneous pain. In numerous studies on animal models of diabetic peripheral neuropathy, behavioural measurements have been largely confined to analysis of evoked withdrawal to mechanical and thermal stimuli applied to dermatomes, whereas spontaneous, on-going pain has not been widely studied. In the Streptozotocin model of type 1 diabetes, we employed the Conditioned Place Preference test to assess tonic pain. Our results indicate that both phases, that is, early evoked hypersensitivity (i.e. 5–7 weeks post-Streptozotocin) as well as late stage hypoalgesia (i.e. 17–20 weeks post-Streptozotocin) are accompanied by significant tonic pain in mice with diabetic peripheral neuropathy. We also report on the temporal relation between on-going pain and neuropathological changes in the dorsal root ganglia of mice with diabetic peripheral neuropathy up to 6 months post-Streptozotocin. Neither early hypersensitivity nor late hypoalgesia were associated with markers of cellular stress in the dorsal root ganglia. Whereas significant neutrophil infiltration was observed in the dorsal root ganglia over both early and late stages post-Streptozotocin, T-cell infiltration in the dorsal root ganglia was prominent at late stages post-Streptozotocin. Thus, longitudinal analyses reveal that similar to patients with chronic diabetic peripheral neuropathy, mice show tonic pain despite sensory loss after several months in the Streptozotocin model, which is accompanied by neuroimmune interactions in the dorsal root ganglia.

Effects of Tongluotangtai recipe on serum pain substances 5-HT, B-EP, histamine and bradykinin in rats with painful diabetic peripheral neuropathy model of streptozotocin (STZ)

Objective: To investigate the effect of Tongluotangtai decoction on 5-HT, β-EP, histamine and bradykinin in serum of STZ rats with pain-related diabetic neuropathy. Methods: The rat model of diabetic peripheral neuropathy was made by intraperitoneal injection of STZ. The rats were divided into control group, model group, Tongluo sugar group and phenytoin. The rats were administrated with saline, Tongluo sugar Thai or phenytoin sodium daily, and the levels of 5- HT, β-EP, histamine and bradykinin in the serum of each group were measured after 3 w, 5 w and 9 w. Results: After 3 w, 5 w and 9 w of drug intervention, the levels of 5-HT, histamine and bradykinin in the model group were significantly higher than those in the control group (P<0.05) and the level of β-EP was significantly reduced. Compared with the model group, the contents of histamine and bradykinin in Tongtao Tangtai group and phenytoin group were significantly decreased and the level of β-EP was significantly reduced. Compared with the rats in the phenytoin group, the contents of histamine and bradykinin in Tongtao Suantai group and phenytoin group were significantly decreased and the level of β-EP was significantly reduced. Conclusion: Tongtao Tangtai decoction can significantly reduce the level of 5-HT, histamine and bradykinin in STZ-induced diabetic neuropathy model rats, increase the content of β-EP and exert a significant anti-pain effect.

Improved memory cognition and retention by Ghrelin in intra-cerebroventricular streptozotocin model in rat

Improved memory cognition and retention by Ghrelin in intra-cerebroventricular streptozotocin model in rat

Changes in the Cardiac GHSR1a-Ghrelin System Correlate With Myocardial Dysfunction in Diabetic Cardiomyopathy in Mice.

Ghrelin and its receptor, the growth hormone secretagogue receptor 1a (GHSR1a), are present in cardiac tissue. Activation of GHSR1a by ghrelin promotes cardiomyocyte contractility and survival, and changes in myocardial GHSR1a and circulating ghrelin track with end-stage heart failure, leading to the hypothesis that GHSR1a is a biomarker for heart failure. We hypothesized that GHSR1a could also be a biomarker for diabetic cardiomyopathy (DCM). We used two models of streptozotocin (STZ)-induced DCM: group 1, adult mice treated with 35 mg/kg STZ for 3 days; and group 2, neonatal mice treated with 70 mg/kg STZ at days 2 and 5 after birth. In group 1, mild fasting hyperglycemia (11 mM) was first detected 8 weeks after the last injection, and in group 2, severe fasting hyperglycemia (20 mM) was first detected 1 to 3 weeks after the last injection. In group 1, left ventricular function was slightly impaired as measured by echocardiography, and Western blot analysis showed a significant decrease in myocardial GHSR1a. In group 2, GHSR1a levels were also decreased as assessed by Cy5-ghrelin(1–19) fluorescence microscopy, and there was a significant negative correlation between GHSR1a levels and glucose tolerance. There were significant positive correlations between GHSR1a and ghrelin and between GHSR1a and sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a), a marker for contractility, but not between GHSR1a and B-type natriuretic peptide, a marker for heart failure. We conclude that the subclinical stage of DCM is accompanied by alterations in the myocardial ghrelin-GHSR1a system, suggesting the possibility of a biomarker for DCM.

Extracellular matrix remodeling and TGF-β1/Smad signaling in diabetic colon mucosa.

Diabetes is associated with metabolic and functional alterations in the gut. Using an experimental model of streptozotocin (STZ)-induced diabetes in rodents, we analyzed the extracellular matrix (ECM) and TGF-β/Smad signaling in the colon mucosa. Male rats were divided into normal control, diabetic and insulin treated diabetic groups during 4 and 9 weeks. Sirius red staining showed marked increase in the extracellular matrix deposition in diabetic mucosa. High levels of fibrillar collagen (I and III) and fibronectin mRNAs were also detected with an imbalance between MMPs/TIMPs activities. Moreover, an increased mesenchymal cell proliferation together with an enhanced expression of myofibroblasts markers vimentin and α-SMA were observed. TGF-β/Smad signaling-related genes were determined using RT-PCR, Western blotting, and immunohistochemistry. Diabetic rats showed a significant up-regulation of TGF-β1, TGF-β receptors and the effectors p-Smad2/3 in the mucosa compared with control rats. Insulin treatment attenuated the stimulating effect of diabetes on colon ECM deposition and TGF-β/Smad signaling. In conclusion, the overall results showed a deregulation of the TGFβ1 pathway associated with the appearance of myofibroblasts and the accumulation of ECM in the mucosa of diabetic colon. These data provide the first in vivo evidence that TGF-β1/Smad is a key component of intestinal tissue remodeling in diabetes.

Naringin prevents bone loss in a rat model of type 1 Diabetes mellitus

The aim of this work was to know whether naringin (NA) could prevent the bone complications in a model of streptozotocin (STZ) induced diabetes. Rats were divided in: 1) controls, 2) STZ-rats, 3) STZ-rats treated with 40 mg NA/kg, and 4) STZ-rats treated with 80 mg NA/kg. BMD and BMC were performed by DEXA. Bone histomorphometry and histology as well as TRAP staining were done in tibia. Osteocalcin (OCN) was determined in bone and serum. Glutathione content and SOD and catalase activities were assayed in bone marrow from femur. The data showed that NA80 increased the BMD and BMC from the long bones of STZ-rats. Both NA40 and NA80 normalized the trabecular number and the trabecular separations. An increase in the number of adipocytes and TRAP(+) cells in tibia from STZ-rats was blocked by NA. NA40 treatment increased the number of OCN(+) cells, but only the NA80 treatment allowed to reach the control values. NA normalized the SOD and catalase activities in bone marrow of femur from STZ-rats. In conclusion, NA avoids alterations in the physical properties and microstructure of bone from STZ-rats probably by stimulation of osteoblastogenesis, inhibition of the osteoclastogenesis and adipogenesis via blocking the oxidative stress.

The Synthetic Microneurotrophin BNN27 Affects Retinal Function in Rats With Streptozotocin-Induced Diabetes.

BNN27, a C17-spiroepoxy derivative of DHEA, was shown to have antiapoptotic properties via mechanisms involving the nerve growth factor receptors (tropomyosin-related kinase A [TrkA]/neurotrophin receptor p75 [p75NTR]). In this study, we examined the effects of BNN27 on neural/glial cell function, apoptosis, and inflammation in the experimental rat streptozotocin (STZ) model of diabetic retinopathy (DR). The ability of BNN27 to activate the TrkA receptor and regulate p75NTR expression was investigated. BNN27 (2,10, and 50 mg/kg i.p. for 7 days) administration 4 weeks post-STZ injection (paradigm A) reversed the diabetes-induced glial activation and loss of function of amacrine cells (brain nitric oxide synthetase/tyrosine hydroxylase expression) and ganglion cell axons via a TrkA receptor (TrkAR)-dependent mechanism. BNN27 activated/phosphorylated the TrkAY490 residue in the absence but not the presence of TrkAR inhibitor and abolished the diabetes-induced increase in p75NTR expression. However, it had no effect on retinal cell death (TUNEL+ cells). A similar result was observed when BNN27 (10 mg/kg i.p.) was administered at the onset of diabetes, every other day for 4 weeks (paradigm B). However, BNN27 decreased the activation of caspase-3 in both paradigms. Finally, BNN27 reduced the proinflammatory (TNFα and IL-1β) and increased the anti-inflammatory (IL-10 and IL-4) cytokine levels. These findings suggest that BNN27 has the pharmacological profile of a therapeutic for DR, since it targets both the neurodegenerative and inflammatory components of the disease.

Early and Persistent O-GlcNAc Protein Modification in the Streptozotocin Model of Alzheimer's Disease.

O-GlcNAc transferase (OGT), an enzyme highly expressed in brain tissue, catalyzes the addition of N-acetyl-glucosamine (GlcNAc) to hydroxyl residues of serine and threonine of proteins. Brain protein O-GlcNAcylation is diminished in Alzheimer's disease (AD), and OGT targets include proteins of the insulin-signaling pathway (e.g., insulin receptor susbtrate-1, IRS-1). We hypothesized that ICV streptozotocin (STZ) also affects O-GlcNAc protein modification. We investigated hippocampal metabolic changes in Wistar rats, particularly OGT levels and insulin resistance, as well as related astroglial activities, immediately after ICV STZ administration (first week) and later on (fourth week). We found an early (at one week) and persistent (at fourth week) decrease in OGT in the ICV STZ model of AD, characterized by a spatial cognitive deficit. Consistent with this observation, we observed a decrease in protein O-GlnNAc modification at both times. Increased phosphorylation at serine-307 of IRS-1, which is related to insulin resistance, was observed on the fourth week. The decrease in OGT and consequent protein O-GlnNAc modifications appear to precede the decrease in glucose uptake and increment of the glyoxalase system observed in the hippocampus. Changes in glial fibrillary acidic protein and S100B in the hippocampus, as well as the alterations in cerebrospinal fluid S100B, confirm the astrogliosis. Moreover, decreases in glutamine synthetase and glutathione content suggest astroglial dysfunction, which are likely implicated in the neurodegenerative cascade triggered in this model. Together, these data contribute to the understanding of neurochemical changes in the ICV STZ model of sporadic AD, and may explain the decreases in protein O-GlcNAc levels and insulin resistance observed in AD.

Islet neuropeptide Y receptors are functionally conserved and novel targets for the preservation of beta-cell mass.

Two unmet therapeutic strategies for diabetes treatment are prevention of beta-cell death and stimulation of beta-cell replication. Our aim was to characterize the role of neuropeptide Y receptors in the control of beta-cell mass. We used endogenous and selective agonists of the NPY receptor system to explore its role in the prevention of beta-cell apoptosis and proliferation in islets isolated from both mouse and human donors. We further explored the intra-cellular signalling cascades involved, using chemical inhibitors of key signalling pathways. As proof of principle we designed a long-acting analogue of [Leu31 Pro34 ]-NPY, an agonist of the islet-expressed Y receptors, to determine if targeting this system could preserve beta-cell mass in vivo. Our data reveal that NPY Y1, 4 and 5 receptor activation engages a generalized and powerful anti-apoptotic pathway that protects mouse and human islets from damage. These anti-apoptotic effects were dependent on stimulating a Gαi-PLC-PKC signalling cascade, which prevented cytokine-induced NFkB signalling. NPY receptor activation functionally protected islets by restoring glucose responsiveness following chemically induced injury in both species. NPY receptor activation attenuated beta-cell apoptosis, preserved functional beta-cell mass and attenuated the hyperglycaemic phenotype in a low-dose streptozotocin model of diabetes. Taken together, our observations identify the islet Y receptors as promising targets for the preservation of beta-cell mass. As such, targeting these receptors could help to maintain beta-cell mass in both type 1 and type 2 diabetes, and may also be useful for improving islet transplantation outcomes.

TRPV1 alterations in urinary bladder dysfunction in a rat model of STZ-induced diabetes

AimsMore than half of diabetic patients experience voiding disorder termed diabetic urinary bladder dysfunction (DBD). Here we have investigated how the alterations in transient receptor potential vanilloid 1 (TRPV1) ion channel expressed in bladder-innervating afferents may contribute to DBD pathogenesis. Main methodsThe rat model of streptozotocin (STZ)-induced diabetes was used. The functional profile of TRPV1 in retrogradely labeled afferent, bladder-innervating dorsal root ganglia (DRG) neurons was examined using patch clamp. The level of TRPV1 transcripts in DRG was assessed with qRT-PCR. TRPV1-dependent component of detrusor smooth muscle (DSM) contractions was studied with muscle strip tensiometry. Key findingsTRPV1-mediated current (ITRPV1) was increased in diabetic animals vs. controls by 42%. The expression of Trpv1 gene was found to be 63% higher in STZ-treated rats compared to controls, consistent with the respective electrophysiological data. Surprisingly, capsaicin-induced contractions of DSM were found to be 3-to-10-fold weaker in diabetic group depending on concentration of the agonist (100nM to 10μM). SignificanceOur findings suggest the dual role of TRPV1 in DBD. On the one hand, the increase of its functional expression may enhance micturition reflex arc functioning. On the other hand, at the local level, the decrease of TRPV1-dependent contractions may contribute to organ decompensation.

Evaluation of the Antioxidant and Antiglycation Effects of Lactarius deterrimus and Castanea sativa Extracts on Hepatorenal Injury in Streptozotocin-Induced Diabetic Rats.

The present study aimed to investigate the beneficial effects of the treatment with extracts from the edible mushroom Lactarius deterrimus (Ld) and the chestnut Castanea sativa (Cs), separately and in combination (MIX Ld/Cs), on oxidative stress and advanced glycation end-product (AGE)-mediated hepatorenal injury in a rat model of streptozotocin (STZ)-induced diabetes by examining pathways responsible for maintenance of redox homeostasis. An experimental model of diabetes was induced in rats by the administration of 40 mg/kg STZ intraperitoneally (i.p.) for 5 consecutive days. The examined extracts were applied separately at a dose of 60 mg/kg i.p. and in combination (60 mg/kg each extract; i.p.) for 4 weeks, starting from the last day of STZ administration. The improvement of hepatorenal function in diabetic rats treated with the extracts was associated with an improved glycemic and lipid status and suppression of oxidative stress and thereby oxidative damage of lipids and DNA. Besides the fact that both extracts inhibited protein glycation and AGE formation in vitro, they also reduced non-enzymatic glycosylation in diabetic rats in vivo. The observed antiglycation activity of the examined extracts (separately and in combination) was accompanied with the inhibition of CML-mediated RAGE/NF-κB activation and reduction of enzymatic O-GlcNAcylation in liver and kidney tissues of diabetic rats. Taken together, these results reveal that the administration of chestnut and mushroom extracts, either individually or together, activates a coordinated cytoprotective response against diabetes-induced hepatorenal injury not only through recovery of the antioxidant defense system of the cell, but also through a marked antiglycation activity.

Neutralization of placental growth factor as a novel treatment option in diabetic retinopathy

The current standard of care in clinical practice for diabetic retinopathy (DR), anti-vascular endothelial growth factor (VEGF) therapy, has shown a significant improvement in visual acuity. However, treatment response can be variable and might be associated with potential side effects. This study was designed to investigate inhibition of placental growth factor (PlGF) as a possible alternative therapy for DR. The effect of the anti-PlGF antibody (PL5D11D4) was preclinically evaluated in various animal models by investigating different DR hallmarks, including inflammation, neurodegeneration, vascular leakage and fibrosis. The in vivo efficacy was tested in diabetic streptozotocin (STZ) and Akimba models and in the laser induced choroidal neovascularization (CNV) mouse model. Intravitreal (IVT) administration of the anti-PlGF antibody was compared to anti-VEGFR-2 antibody (DC101), anti-VEGF antibody (B20), VEGF-Trap (aflibercept) and triamcinolone acetonide (TAAC). Vascular leakage was investigated in the mouse STZ model by fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) perfusion and in the Akimba model by fluorescein angiography (FA). Repeated IVT administration of the anti-PlGF antibody reduced vascular leakage, which was comparable to a single administration of VEGFR-2 inhibition in the mouse STZ model. PL5D11D4 treatment did not alter retinal ganglion cell (RGC) density, as demonstrated by Brn3a staining, whereas DC101 significantly reduced RGC number with 20%. Immunohistological stainings were performed to investigate inflammation (CD45, F4/80) and fibrosis (collagen type 1a). In the CNV model, IVT injection(s) of PL5D11D4 dose-dependently reduced inflammation and fibrosis, as compared to PBS treatment. Equimolar single administration of the anti-PlGF antibody and aflibercept (21 nM) and TAAC decreased leukocyte and macrophage infiltration with 50%, whereas DC101 and B20 (21 nM) had no effect on the inflammatory response. Similar results were observed in the mouse STZ model on the number of microglia and macrophages in the retina. Repeated administration of PL5D11D4 (21 nM) and TAAC similarly reduced fibrosis, while no effect was observed after equimolar DC101, B20 nor aflibercept administration (21 nM). In summary, the anti-PlGF antibody showed comparable efficacy as well-characterized VEGF-inhibitor on the process of vascular leakage, but differentiates itself by also reducing inflammation and fibrosis, without triggering a neurodegenerative response.

Carbon monoxide regulates glycolysis-dependent NLRP3 inflammasome activation in macrophages

Low dose of carbon monoxide (CO) has anti-inflammatory role through various signaling pathways. Cellular metabolism has been implicated in the activation of inflammation in immune cells. However, the mechanisms by which CO-dependent metabolic regulation affect the immune response remain unclear. Here we show that CO-dependent metabolic pathway regulates the activation of the nucleotide-binding domain, leucine-rich-repeat-containing receptor (NLR), pyrin-domain-containing 3 (NLRP3) inflammasome. CO-releasing molecule-3 (CORM-3) resulted in reduced glycolysis-dependent NLRP3 inflammasome activation in macrophages. The reduced mTORC1 activation by CORM-3 resulted in less glycolysis during NLRP3 inflammasome activation. CORM-3 suppressed caspase-1 activation and the secretion of interleukin (IL)-1β and IL-18 in macrophages in response to lipopolysaccharide (LPS) and ATP. Moreover, CORM-3 inhibits the oligomerization of the adaptor protein apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), which is required for NLRP3-dependent caspase-1 activation. Furthermore, CORM-3-treated mice showed substantial reduction in IL-1β production by hyperglycemia in a mouse model of streptozotocin (STZ)-induced diabetes. Our results suggest that CO regulates glycolysis-dependent NLRP3 inflammasome activation and may provide a therapeutic approach for inflammation in metabolic diseases.

Specific efficiency of microemulsion matrix transdermal delivery system of insulin (experimental model of diabetes mellitus typeI)

Aim. To study the specific activity of the microemulsion form of the matrix insulin transdermal delivery system in vivo on the experimental streptozotocin model of type I diabetes.Materials and methods.Male rats (n = 25) were randomized to the experimental and control groups. TDS insulin with a microemulsion composition was applicated to the animals of the experimental group (n = 15) for 4 days with daily replacement of TDS and control of the glycemia level. The glycemia level of the control group rats (n = 10) was determined throughout the experiment. The blood glucose concentration was measured using glucometer One Touch Select (USA). Results.The average blood glucose level in experimental group was 28.4 ± 2.3 mmol/l before application of TDS insulin. The average glycemic index was 21.2 ± 3.1 mmol/l (p &lt; 0.001) during of TDS application. The blood glucose decrease was 26 ± 8% relative to baseline values. The glycemia was 28.4 ± 1.4 mmol/l in the control group rats throughout the experiment.Conclusion.A significant decrease of blood glucose level with TDS insulin application in rats with experimental type 1 diabetes demonstrates the existence of the specific activity of the microemulsion matrix transdermal delivery system of insulin.

Evaluation of the neonatal streptozotocin model of diabetes in rats: Evidence for a model of neuropathic pain.

The purpose of this study was to evaluate the participation of satellite glial cells (SGC), microglia and astrocytes in a model of streptozotocin-induced diabetes initiated in neonatal rats (nSTZ) and to determine the pharmacological profile for pain relief. nSTZ was used to induce experimental diabetes. Von Frey filaments were used to assess tactile allodynia. Drugs were given by systemic administration. Western blotting and immunohistochemistry were used to determine protein expression and cellular localization. nSTZ produced mild hyperglycemia, weight loss, glucose intolerance, and reduction of nerve conduction velocity of C fibers. Moreover, nSTZ enhanced activating transcription factor 3 (ATF3) immunoreactivity in dorsal root ganglia (DRG) and sciatic nerve of adult rats. ATF3 was found in SGC (GFAP+ cells) surrounding DRG at week 16. Late changes in ATF3 immunoreactivity in DRG correlated with up-regulation of ATF3 and GFAP protein expression. nSTZ increased GFAP and OX-42 immunoreactivity and percentage of hypertrophied and ameboid microglia in the spinal dorsal horn. These changes correlated with the presence of mechanical hypersensitivity (tactile allodynia). Administration of gabapentin (30-100mg/kg, po) and metformin (200mg/kg/day, po for 2 weeks) alleviated tactile allodynia, whereas morphine (1-3mg/kg, ip) had a modest effect. Results suggest that nSTZ leads to activation of SGC, microglia and astrocytes in DRG and spinal cord. Pharmacological profile in the nSTZ model resembles diabetic neuropathic pain in humans. Our findings support the conclusion that the nSTZ rat model has utility for the study of a long-lasting diabetic neuropathic pain.