Diabetes mellitus exacerbates inflammation in a murine model of ligature-induced peri-implantitis: A histological and microtomographic study.

AIM: To investigate the influence of diabetes mellitus (DM) in a murine model of peri-implantitis (PI). MATERIALS AND METHODS: Twenty-seven 4-week-old C57BL/6J male mice had their first and second maxillary left molars extracted. Eight weeks later, one machined implant was placed in each mouse. Four weeks after osseointegration, the mice were divided into three groups: (a) control (C), (b) PI and (c) DM + PI. DM was induced by streptozotocin (STZ) administration. After DM induction, PI was induced using ligatures for 2 weeks. The hemimaxillae were collected for micro-CT and histological analyses. The primary outcomes consisted of linear (mm) and volumetric (mm3) bone loss. Secondary outcomes were based on histological analysis and included inflammatory infiltrate, osteoclastic activity, matrix organization, composition and remodelling. Data are presented as means ± SEM. Statistical analyses were performed using one-way ANOVA, followed by Tukey's test. RESULTS: Gingival tissue oedema was detected in the PI and DM + PI groups. Micro-CT showed significantly increased linear and volumetric bone loss in the DM + PI group compared to the C and PI groups. H&E staining showed greater inflammatory response and bone resorption in the PI and DM + PI groups than in the C group. The DM + PI group had significantly higher osteoclast numbers than the C and PI groups. Picrosirius red stained less for types I and III collagen in the PI and DM + PI groups than in the C group. There was a significant increase in monocyte/macrophage (CD-11b) counts and matrix metalloproteinases (MMP-2 and MMP-8) marker levels and a significant decrease in the matrix metalloproteinases inhibition marker (TIMP-2) levels in the DM + PI group compared to the C and PI groups. CONCLUSIONS: DM exacerbates PI-induced soft-tissue inflammation, matrix degradation and bone loss.

Damage to Nuclear and Mitochondrial DNA in Different Organs in Streptozotocin-Induced Diabetes Models in BALB/c Mice.

Male BALB/c mice with streptozotocin-induced diabetes mellitus were used to study nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) damage using comet DNA assay and real-time PCR, respectively. In animals receiving single injection of streptozotocin in a dose of 200 mg/kg, severe hyperglycemia was observed on days 10 and 21 of the experiment, while after 5-fold administration of streptozotocin in a dose of 40 mg/kg, it developed on days 14 and 28. DNA damage and the level of atypical DNA comets in the liver increased both on days 10 and 21 after single administration of streptozotocin, and on days 14 and 28 after repeated administrations. The level of atypical DNA comets on day 21 after a single administration of streptozotocin increased in the kidneys, but not in the brain, testes, and pancreas. Real-time PCR revealed mtDNA damage in the liver, kidney, and pancreatic cells of mice with streptozotocin-induced diabetes. Thus, these animal models were found to reproduce pathognomic signs of diabetes, hyperglycemia, and nDNA damage; mtDNA damage was also detected.

MORPHOLOGICAL CHARACTERISTICS OF THE ENDOCRINE FUNCTION OF THE HEART IN COMORBID PATHOLOGY.

OBJECTIVE: Aim: To study the ultrastructural remodeling of atrial myoendocrine cells (AMC) of the atrial myocardium in streptozotocin-induced diabetes (SID) under chronic immobilization stress (CIS). PATIENTS AND METHODS: Materials and methods: 40 sexually mature white male rats (body weight 150-180 g) were included in the study. Four groups were formed: group 1 - animals with comorbid pathology (SID and CIS), group 2 - animals with SID, group 3 - animals with CIS, group 4 - intact animals. RESULTS: Results: On the 14th day of the development of SID and CIS, an increase in the functional activity of AMC is noted, which is confirmed by hyperplasia and hypertrophy of the protein-synthesizing apparatus, an increase in the volume density of secretory granules (SG), especially diffusing ones, and indicates enhanced release of atrial natriuretic peptide (ANP) from cells during the experiment. On the 56th day of the experiment, in groups 1 and 2 of , destructive changes in AMC were noted, such as vacuolar and balloon dystrophy, colliquative and partial necrosis. At the same time, the functional activity of AMC of different regions of the myocardium significantly. In animals with CIS, the volume density of young and diffusing SG in AMC is decreased. CONCLUSION: Conclusions: Therefore, in the early stages of the development of SID and CIS, an increase in the morpho-functional activity of AMC is noted. The long course of SID and its combination with CIS lead to destructive changes in AMC and to decrease in their secretory activity.

Effects of first-line diabetes therapy with biguanides, sulphonylurea and thiazolidinediones on the differentiation, proliferation and apoptosis of islet cell populations.

AIMS: Metformin, rosiglitazone and sulfonylureas enhance either insulin action or secretion and thus have been used extensively as early stage anti-diabetic medication, independently of the aetiology of the disease. When administered to newly diagnosed diabetes patients, these drugs produce variable results. Here, we examined the effects of the three early stage oral hypoglycaemic agents in mice with diabetes induced by multiple low doses of streptozotocin, focusing specifically on the developmental biology of pancreatic islets. METHODS: Streptozotocin-treated diabetic mice expressing a fluorescent reporter specifically in pancreatic islet α-cells were administered the biguanide metformin (100 mg/kg), thiazolidinedione rosiglitazone (10 mg/kg), or sulfonylurea tolbutamide (20 mg/kg) for 10 days. We assessed the impact of the treatment on metabolic status of the animals as well as on the morphology, proliferative potential and transdifferentiation of pancreatic islet cells, using immunofluorescence. RESULTS: The effect of the therapy on the islet cells varied depending on the drug and included enhanced pancreatic islet ß-cell proliferation, in case of metformin and rosiglitazone; de-differentiation of α-cells and ß-cell apoptosis with tolbutamide; increased relative number of ß-cells and bi-hormonal insulin + glucagon + cells with metformin. These effects were accompanied by normalisation of food and fluid intake with only minor effects on glycaemia at the low doses of the agents employed. CONCLUSIONS: Our data suggest that metformin and rosiglitazone attenuate the depletion of the ß-cell pool in the streptozotocin-induced diabetes, whereas tolbutamide exacerbates the ß-cell apoptosis, but is likely to protect ß-cells from chronic hyperglycaemia by directly elevating insulin secretion.

Fruit Extract Derived from a Mixture of Noni, Pineapple and Mango Capable of Coagulating Milk and Producing Curd with Antidiabetic Activities.

Research background: Morinda citrifolia L. (noni), Ananas comosus L. cv. Sarawak (pineapple) and Mangifera indica L. cv. Apple (mango) represent fruits capable of coagulating milk and forming a curd. Plant-derived milk coagulants have antidiabetic phytochemicals that enrich the curd. Hence this work evaluates the dual benefits of the fruits in coagulating milk and the antidiabetic activities found in the obtained curd. Experimental approach: The three fruits were mixed to form a supercoagulant (a milk coagulant mixture of the extracts at a ratio of 1:1:1), and the milk coagulation time was measured. The milk was coagulated by the supercoagulant, and thus fortified curd was tested for its ability to inhibit α-glucosidase and α-amylase activities. Then, the fortified curd was fed daily to streptozotocin-induced diabetic rats and their biochemical markers such as blood glucose level, aspartate aminotransferase, alanine transaminase, etc. as well as histopathology of their liver and kidney tissues were compared with the untreated diabetic rats and normal rats. Results and conclusion: The supercoagulant had a milk coagulation time of (28±3) s at a 50 mg/mL concentration. Its fortified curd inhibited α-glucosidase and α-amylase activities, with IC50 values of (4.04±0.03) and (3.42±0.02) mg/mL, respectively. The average mass of the streptozotocin-induced diabetic rats fed daily with curd formed by the supercoagulant was (201±10) g on day 20 compared to diabetic control rats with (149±16) g. The blood glucose concentration for rats treated with the supercoagulant after fasting was (15±1) mmol/L compared to the diabetic control rats ((26±2) mmol/L). Blood tests on the treated rats showed aspartate aminotransferase, alanine transaminase, γ-glutamyl transferase and alkaline phosphatase (liver function tests) amounts of (214±78), (91±13), 3 and (510±138) U/L, respectively, while the total protein and renal function tests showed the concentrations of albumin, globulin, urea and creatinine of (37±2) g/L, (30±2) g/L, (11±1) mmol/L and (42±3) µmol/L, respectively. These concentrations were found to be similar to those of the normal rats on day 20. Furthermore, a histopathological study performed on the liver and kidney of the rats found no apparent damage. Novelty and scientific contribution: This supercoagulant derived from a mixture of fruits is able to coagulate milk rapidly, and its curd is fortified with safe antidiabetic agents. The supercoagulant is potentially useful in producing functional dairy food to prevent diabetes or as a supplement for diabetics to control their blood sugar. Such products are capable of replacing dairy products derived from animal enzymes and provide consumers with additional functional dairy products.

MORPHOLOGICAL CHARACTERISTICS OF DIABETIC GLOSSITIS.

OBJECTIVE: The aim: To identify characteristic features of structural change of the dorsal part of the mucous membrane of the tongue (MMT) in experimental streptozotocin-induced diabetes (ESID). PATIENTS AND METHODS: Materials and methods: The study included 20 adult white male rats of Vistar line (body weight 180-200 g), which were equally divided into 2 groups: experimental (simulated streptozotocin diabetes mellitus) and control ones. RESULTS: Results: 8 weeks after the beginning of ESID modeling, the changes in MMT are particularly pronounced. A large number of lamellar structures and keratin conglomerates are found on the surface of MMT. This phenomenon is closely correlated (r=0.70) with a decrease in the absorption capacity of superficial epitheliocytes and an increase in the number of heterogeneous microflora on the impression smear with low activity of leukocyte elements. The number of epitheliocytes of differentiation stages I-III continues to increase, and the number of epitheliocytes of differentiation stages IV-VI diminishes, which leads to a significant decrease in the index of cell differentiation and an increase in the nuclear-cytoplasmic ratio. Such changes in MMT impression smears indicate active processes of epithelial desquamation with increasing duration of ESID. CONCLUSION: Conclusions: Thus, the morphological changes of MMT in ESID are characterized by a diverse combination of atrophic and hyperplastic processes, resulting in uneven thickening of multilayered squamous epithelium. There are pronounced dystrophic changes in the epitheliocytes of the stratum corneum (dyskeratosis, parakeratosis) in the area of the taste buds. All areas of MMT are inflamed which indicates the development of diabetic glossitis.

STZ-diabetic rat heart maintains developed tension amplitude by increasing sarcomere length and crossbridge density.

NEW FINDINGS: What is the central question of this study? In the papillary muscle from type I diabetic rats, does diabetes-associated altered ventricular function result from changes of acto-myosin interactions and are these modifications attributable to a possible sarcomere rearrangement? What is the main finding and its importance? For the first time, we showed that type-I diabetes altered sarcomeric ultrastructure, as seen by transmission electron microscopy, consistent with physiological parameters. The diabetic condition induced slower timing parameters, which is compatible with a diastolic dysfunction. At the sarcomeric level, augmented ß-myosin heavy chain content and increased sarcomere length and crossbridges' number preserve myocardial stroke and could concur to maintain the ejection fraction. ABSTRACT: We investigated whether diabetes-associated altered ventricular function, in a type I diabetes animal model, results from a modification of acto-myosin interactions, through the in vitro recording of left papillary muscle mechanical parameters and examination of sarcomere morphology by transmission electron microscopy (TEM). Experiments were performed on streptozotocin-induced diabetic and age-matched control female Wistar rats. Mechanical isometric and isotonic indexes and timing parameters were determined. Using Huxley's equations, we calculated mechanics, kinetics and energetics of myosin crossbridges. Sarcomere length and A-band length were measured on TEM images. Type I and III collagen and ß-myosin heavy chain (MHC) expression were determined by immunoblotting. No variation in resting and developed tension or maximum extent of shortening was evident between groups, but diabetic rats showed lower maximum shortening velocity and prolonged timing parameters. Compared to controls, diabetics also displayed a higher number of crossbridges with lower unitary force. Moreover, no change in type I and III collagen was associated to diabetes, but pathological rats showed a two-fold enhancement of ß-MHC content and longer sarcomeres and A-band, detected by ultrastructural morphometry. Overall, these data address whether a preserved systolic function accompanied by an altered diastolic phase results from a recruitment of super-relaxed myosin heads or the phosphorylation of the regulatory light chain site in myosin. Although the early signs of diabetic cardiomyopathy were well expressed, the striking finding of our study was that, in diabetics, sarcomere modification may be a possible compensatory mechanism that preserves systolic function.

Reduced sexual motivation of diabetic female rats: Restoration with insulin.

The aim of this study was to evaluate female rat sexual motivation in a model of diabetes mellitus type 1. Severe hyperglycemia was induced in ovariectomized Wistar rats by injecting streptozotocin [STZ, 100 mg/kg, i.p.]. Ten days later, females received estradiol benzoate (10 µg/rat, s.c.) plus progesterone (3 mg/rat, s.c.). A group of STZ-treated animals was administered with insulin (2-4 U) every 12 h for 10 days, which normalized glucose levels. In the partner preference (PP) and sexual incentive motivation (SIM) tests, control females spent more time close to a sexually experienced male (SE) than with a castrated male (CM). STZ-treated females stayed the same amount of time with both stimuli, that is, they lost their sexual preference. We also evaluated the sense of smell using two behavioral tests, one related to sexual odors (SO) and another one to food odors (FO). In the SO test, control females spent more time sniffing the sawdust coming from cages that contained SE males; hyperglycemic females remained the same amount of time sniffing the sawdust of both stimuli: SE and CM. In the FO test, no differences were found between control and STZ-treated groups. Insulin treatment reverted the changes observed in hyperglycemic females in the PP, SIM and SO tests. These data suggest that severe hyperglycemia decreases sexual motivation and that insulin recovers such diminution.

The ameliorative role of Physalis pubescens L. against neurological impairment associated with streptozotocin induced diabetes in rats.

Neuropathy is considered a critical complication of diabetes mellitus (DM). Scientific studies are needed to relieve these painful complications. The current study aims to estimate the ameliorative role of Physalis juice (PJ) against neurological impairment in streptozotocin (STZ)-induced diabetic rats. Type 1 DM was induced after one week of injecting rats with 55 mg STZ/kg body weight. PJ-treated rats were orally administered 5 ml PJ/kg body weight per day for 28 days after induction of diabetes. A small piece of the cerebral cortex of rats was fixed and used for histopathological investigations. The remaining portion of the cerebral cortex was homogenized for biochemical and molecular analyses. As compared to the controls, STZ-injected rats showed significant elevations in the levels of blood glucose, tumor necrosis factor alfa, interleukin-1ß, malondialdehyde, nitric oxide, and expression levels of caspase-3 and B-cell lymphoma-2 associated X-protein. Additionally, remarkable declines in the levels of brain-derived neurotrophic factor, monoamines, B-cell lymphoma-2, glutathione, as well as the activities and gene expression levels of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in STZ-treated rats were reported. Moreover, some histopathological alterations were observed in the brain cortex of the STZ-treated rats. On the other hand, the administration of PJ substantially reduced the blood glucose and alleviated the above-mentioned alterations in all the studied parameters of the cerebral cortex. In conclusion, an oral administration of 5 ml PJ/kg revealed a neuroprotective action against neurodegenerative diabetes-induced complications in rats, which might be due to the reported antioxidative and anti-inflammatory actions of PJ. Thus, further therapeutic studies are recommended to apply PJ in the treatment regimen of diabetes.

Effects of sitagliptin on ß-adrenoceptor mediated relaxation in streptozotocin-diabetic rat aorta

Background/aim: Dipeptidyl peptidase-4 (DPP4) inhibitors, a class of oral antidiabetic drugs, have been shown to be protective on the vascular system because of their antiinflammatory, antiatherosclerotic, and vasodilatory effects. ß2-adrenoceptors (ß2-ARs) mediate the vasorelaxation in the aorta. However, ß3-adrenoceptor-mediated relaxation has not been studied in diabetic aorta yet. Thus, we aimed to study the effect of sitagliptin treatment on ß2- and ß3-adrenoceptor-mediated relaxations in the diabetic rat aorta. Materials and methods: Eight-week old Sprague Dawley rats were divided into three groups: control, diabetic, sitagliptin treated diabetic. Diabetes was induced by injection of streptozotocin (35 or 40 mg/kg, intraperitoneally). After 10 weeks of diabetes, some of the diabetic rats were treated with sitagliptin (orally, 10mg/kg/day). ß2- and ß3-AR-mediated relaxation responses were evaluated by using isoprenaline and CL 316,243, respectively. ß3-AR-mediated relaxation experiments were repeated in presence of L-NAME. Western blotting and immunohistochemistry were performed to determine the abundance of ß3-adrenoceptor and endothelial nitric oxide synthase (eNOS). Results: The isoprenaline-mediated relaxation response was impaired in the diabetic group and sitagliptin treatment did not improve it. There was no significant change in CL316,243 mediated-relaxation or protein expression of ß3-ARs among the groups. However, the ratio of phosphorylated eNOS/NOS protein was increased markedly in the sitagliptin treated group, which points the stimulating effect of this drug towards the eNOS pathway. Conclusion: Our results indicate that sitagliptin treatment does not alter ß-AR-mediated relaxation in streptozotocin-diabetic rat aorta; however, it significantly stimulates the eNOS pathway. Future studies are needed to clarify the relationship between the eNOS pathway and DPP-4 inhibition.

Downregulation of long noncoding RNA H19 rescues hippocampal neurons from apoptosis and oxidative stress by inhibiting IGF2 methylation in mice with streptozotocin-induced diabetes mellitus.

The diabetes mellitus (DM)-induced reduction of neurogenesis in the hippocampus is consequently accompanied by cognitive decline. The present study set out to define the critical role played by long noncoding RNA H19 (lncRNA H19) in the apoptosis of hippocampal neurons, as well as oxidative stress (OS) in streptozotocin (STZ)-induced DM mice through regulation of insulin-like growth factor 2 (IGF2) methylation. The expression of lncRNA H19 in the hippocampal neurons and surviving neurons were detected. Hippocampal neurons were cultured and transfected with oe-H19, sh-H19, oe-IGF2, or sh-IGF2, followed by detection of the expressions of IGF2 and apoptosis-related genes. Determination of the lipid peroxide and glutathione levels was conducted, while antioxidant enzyme activity was identified. The IGF2 methylation, the binding of lncRNA H19 to DNA methyltransferase, and the binding of lncRNA H19 to IGF2 promoter region were detected. DM mice exhibited high expressions of H19, as well as a decreased hippocampal neurons survival rate. Higher lncRNA H19 expression was found in DM. Upregulated lncRNA H19 significantly increased the expression of Bax and caspase-3 but decreased that of Bcl-2, thus promoting the apoptosis of hippocampal neuron. Besides, upregulation of lncRNA H19 induced OS. LncRNA H19 was observed to bind specifically to the IGF2 gene promoter region and promote IGF2 methylation by enriching DNA methyltransferase, thereby silencing IGF2 expression. Taken together, downregulated lncRNA H19 reduces IGF2 methylation and enhances its expression, thereby suppressing hippocampal neuron apoptosis and OS in STZ-induced (DM) mice.

Possible involvement of peripheral TRP channels in the hydrogen sulfide-induced hyperalgesia in diabetic rats.

BACKGROUND: Peripheral diabetic neuropathy can be painful and its symptoms include hyperalgesia, allodynia and spontaneous pain. Hydrogen sulfide (H2S) is involved in diabetes-induced hyperalgesia and allodynia. However, the molecular target through which H2S induces hyperalgesia in diabetic animals is unclear. The aim of this study was to determine the possible involvement of transient receptor potential (TRP) channels in H2S-induced hyperalgesia in diabetic rats. RESULTS: Streptozotocin (STZ) injection produced hyperglycemia in rats. Intraplantar injection of NaHS (an exogenous donor of H2S, 3-100 µg/paw) induced hyperalgesia, in a time-dependent manner, in formalin-treated diabetic rats. NaHS-induced hyperalgesia was partially prevented by local intraplantar injection of capsazepine (0.3-3 µg/paw), HC-030031 (100-316 µg/paw) and SKF-96365 (10-30 µg/paw) blockers, at 21 days post-STZ injection. At the doses used, these blockers did not modify formalin-induced nociception. Moreover, capsazepine (0.3-30 µg/paw), HC-030031 (100-1000 µg/paw) and SKF-96365 (10-100 µg/paw) reduced formalin-induced nociception in diabetic rats. Contralateral injection of the highest doses used did not modify formalin-induced flinching behavior. Hyperglycemia, at 21 days, also increased protein expression of cystathionine-ß-synthase enzyme (CBS) and TRPC6, but not TRPA1 nor TRPV1, channels in dorsal root ganglia (DRG). Repeated injection of NaHS enhanced CBS and TRPC6 expression, but hydroxylamine (HA) prevented the STZ-induced increase of CBS protein. In addition, daily administration of SKF-96365 diminished TRPC6 protein expression, whereas NaHS partially prevented the decrease of SKF-96365-induced TRPC6 expression. Concordantly, daily intraplantar injection of NaHS enhanced, and HA prevented STZ-induced intraepidermal fiber loss, respectively. CBS was expressed in small- and medium-sized cells of DRG and co-localized with TRPV1, TRPA1 and TRPC6 in IB4-positive neurons. CONCLUSIONS: Our data suggest that H2S leads to hyperalgesia in diabetic rats through activation of TRPV1, TRPA1 and TRPC channels and, subsequent intraepidermal fibers loss. CBS enzyme inhibitors or TRP-channel blockers could be useful for treatment of painful diabetic neuropathy.

Hypoxic pulmonary vasoconstriction is lacking in rats with type 1 diabetes.

Hypoxic pulmonary vasoconstriction (HPV) is the most important feature of intact lung circulation that matches local blood perfusion to ventilation. The main goal of this work was to study the effects of diabetes on the development of HPV in rats. The experimental design comprised diabetes mellitus induction by streptozotocin, video-morphometric measurements of the lumen area of intrapulmonary arteries (iPAs) using perfused lung tissue slices and patch-clamp techniques. It was shown that iPA lumen size was significantly reduced under physical and chemical hypoxia (7-10 mm Hg) in normal iPA, but, on the contrary, it clearly increased in diabetic lung slices. The amplitude of the outward K+ current in diabetic iPAs smooth muscle cells (SMCs) was two-fold greater than that seen in healthy cells. Chemical hypoxia led to significant decrease in the amplitude of the K+ outward current in healthy iPA SMCs while it was without effect in diabetic cells. The data obtained clearly indicate a significant dysregulation of vascular tone in pulmonary circulation under diabetes, ie diabetes damages the adaptive mechanism for regulating blood flow from poorly ventilated to better ventilated regions of the lung under hypoxia. This effect could be clinically important for patients with diabetes who have acute or chronic lung diseases associated with the lack of blood oxygenation.

Low-Energy Extracorporeal Shock Wave Ameliorates Streptozotocin Induced Diabetes and Promotes Pancreatic Beta Cells Regeneration in a Rat Model.

Traditional therapy for diabetes mellitus has focused on supportive treatment, and is not significant in the promotion of pancreatic beta cells regeneration. We investigated the effect of low- energy extracorporeal shock wave (SW) on a streptozotocin induced diabetes (DM) rat model. METHODS: The DM rats were treated with ten sessions of low-energy SW therapy (weekly for ten consecutive weeks) or left untreated. We assessed blood glucose, hemoglobin A1c (HbA1c), urine volume, pancreatic islets area, c-peptide, glucagon-like peptide 1 (GLP-1) and insulin production, beta cells number, pancreatic tissue inflammation, oxidative stress, apoptosis, angiogenesis, and stromal cell derived factor 1 (SDF-1) ten weeks after the completion of treatment. RESULTS: The ten- week low-energy SW therapy regimen significantly reduced blood glucose, HbA1c, and urine volume as well as significantly enhancing pancreatic islets area, c-peptide, GLP-1, and insulin production in the rat model of DM. Moreover, low-energy SW therapy increased the beta cells number in DM rats. This was likely primarily attributed to the fact that low-energy SW therapy reduced pancreatic tissue inflammation, apoptosis, and oxidative stress as well as increasing angiogenesis, cell proliferation, and tissue repair potency. CONCLUSIONS: Low-energy SW therapy preserved pancreatic islets function in streptozotocin-induced DM. Low-energy SW therapy may serve as a novel noninvasive and effective treatment of DM.

Antidiabetic and Antioxidative Potential of the Blue Congo Variety of Purple Potato Extract in Streptozotocin-Induced Diabetic Rats.

This study was designed to evaluate the effects of purple potato extract of the Blue Congo variety (PP) on diabetes and its antioxidant activities after two-week administration tostreptozotocin (STZ)-induced diabetic rats. The activities of PP were evaluated at a dose of 165 mg/kg body weight (b.w.) by estimating biochemical changes in blood plasma and through a histopathological study of kidney, muscles, and liver tissue. We evaluated the effect of treatment with extract on glucose level, glycated hemoglobin, activities of enzymatic antioxidants (including superoxide dismutase, glutathione peroxidase, and catalase), and lipid peroxidation. Moreover, we determined advanced glycation end-products (AGEs), advanced oxidation protein products (AOPPs), and the level of oxidative modified proteins (OMPs) as markers of carbonyl-oxidative stress in rats with diabetes. Using high-performance liquid chromatography, we identified five anthocyanins and six phenolic acids in the extract from Blue Congo with the dominant acylated anthocyanin as petunidin-3-p-coumaroyl-rutinoside-5-glucoside. The administration of Blue Congo extract lowered blood glucose, improved glucose tolerance, and decreased the amount of glycated hemoglobin. Furthermore, PP demonstrated an antioxidative effect, suppressed malondialdehyde levels, and restored antioxidant enzyme activities in diabetic rats. After administration of PP, we also noticed inhibition of OMP, AGE, and AOPP formation in the rats' blood plasma.

Reduced Lordosis and Enhanced Aggression in Paced and Non-Paced Mating in Diabetic Female Rats.

BACKGROUND: Clinical studies have shown altered sexual function in people with diabetes; basic science studies, using the streptozotocin (STZ)-induced animal model of type 1 diabetes mellitus (DM1), have consistently reported decreased sexual behavior in hyperglycemic female animals, but features of sexual motivation and aggressive behavior have not been explored in these animals. AIM: To study several parameters that denote sexual motivation in STZ-treated female rats and to compare behavioral features of sexual behavior and aggression in non-paced mating (NPM) and paced mating (PM) conditions. METHODS: DM1 was induced by injecting STZ (diluted in citrate buffer) at a dose of 50 mg/kg intraperitoneally over 2 consecutive days into ovariectomized Wistar rats. 10 days later, female rats were treated with estradiol benzoate (10 µg, -24 hours) and progesterone (3 mg, -4 hours); their sexual behavior (including lordosis quotient, lordosis intensity, and proceptivity) and aggression were evaluated under NPM and PM conditions. Body weight, blood glucose levels, and spontaneous ambulatory activity also were measured. A group of STZ-treated animals was administered a long-acting insulin analogue (glargine) every 12 hours for 8 days, and their sexual and aggressive behaviors were evaluated in NPM. OUTCOMES: We quantified body weight, blood glucose level, spontaneous ambulatory activity, and sexual and aggressive behaviors in NPM and PM; the time the female rats spent interacting with the male rat or in the male rat's chamber also was registered in PM. RESULTS: Compared with controls, STZ-treated ovariectomized rats lost body weight, had increased blood glucose levels, and had unchanged spontaneous ambulatory activity. In the PM and NPM conditions, animals showed decreased lordosis quotient and lordosis intensity, increased aggression, and unaltered proceptivity, although in NPM the effects of STZ treatment on aggression were more drastic and were completely prevented by insulin. In PM no differences were found between diabetic and control female rats in the time interacting with the male rat or in the male rat's chamber. CLINICAL TRANSLATION: These findings support the observation of increased prevalence of sexual dysfunctions and aggression in the clinical setting of DM1. STRENGTHS AND LIMITATIONS: The main strength of this study is that it analyzed sexual behavior under PM and NPM conditions and aggression in STZ-treated female rats. Its main limitations are that the model of DM1 represents only 10% of the affected population and that no specific treatment is proposed for the sexual dysfunctions. CONCLUSION: These results suggest that STZ-treated rats have decreased sexual receptivity in NPM and PM, accompanied by increased aggressiveness in NPM. Hernández-Munive AK, Rebolledo-Solleiro D, Ventura-Aquino E, Fernández-Guasti A. Reduced Lordosis and Enhanced Aggression in Paced and Non-Paced Mating in Diabetic Female Rats. J Sex Med 2018;15:124-135.

Time-dependent therapeutic roles of nitazoxanide on high-fat diet/streptozotocin-induced diabetes in rats: effects on hepatic peroxisome proliferator-activated receptor-gamma receptors.

Targeting peroxisome proliferator-activated receptor-gamma (PPAR-γ) is an approved strategy in facing insulin resistance (IR) for diabetes mellitus (DM) type 2. The PPAR-γ modulators display improvements in the insulin-sensitizing and adverse effects of the traditional thiazolidinediones. Nitazoxanide (NTZ) is proposed as a PPAR-γ receptor ligand with agonistic post-transcriptional effects. Currently, NTZ antidiabetic activities versus pioglitazone (PIO) in a high-fat diet/streptozotocin rat model of type 2 diabetes was explored. Diabetic adult male Wistar rats were treated orally with either PIO (2.7 mg·kg-1·day-1) or NTZ (200 mg·kg-1·day-1) for 14, 21, and 28 days. Body masses, fasting blood glucose, IR, lipid profiles, and liver and kidney functions of rats were assayed. Hepatic glucose metabolism and PPAR-γ protein expression levels as well as hepatic, pancreatic, muscular, and renal histopathology were evaluated. Significant time-dependent euglycemic and insulin-sensitizing effects with preservation of liver and kidney functions were offered by NTZ. Higher hepatic levels of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase enzymes and PPAR-γ protein expressions were acquired by NTZ and PIO, respectively. NTZ could be considered an oral therapeutic strategy for DM type 2. Further systematic NTZ/PPAR-γ receptor subtype molecular activations are recommended. Simultaneous use of NTZ with other approved antidiabetics should be explored.

The effect of lipoic acid in the prevention of myocardial infarction in diabetic rats.

OBJECTIVES: We aimed to investigate the effect of lipoic acid in the prevention of myocardial infarction in diabetic rats. METHODS: Rats were divided into five groups as control, ISO, LA+ISO, STZ+ISO and STZ+LA+ISO. To induce diabetes, single dose of streptozotocin was injected to STZ+ISO and STZ+LA+ISO groups. Lipoic acid (10 mg/kg/day) was injected for 14 days to LA+ISO and STZ+LA+ISO groups. To induce myocardial infarction, isoproterenol was injected to ISO, LA+ISO, STZ+ISO and STZ+LA+ISO groups on the days 13 and 14 of lipoic acid treatment. Cardiac necrosis and leucocyte infiltration were investigated histopathologically. Serum malondialdehyde levels, paraoxonase and lactonase activities were measured spectrophotometrically. RESULTS: Isoproterenol caused a significant increase in cardiac necrosis, leucocyte infiltration and serum lipid peroxidation whereas a significant decrease in serum paraoxonase and lactonase activities. In myocardial infarcted non-diabetic rats, while lipoic acid caused a significant decrease in cardiac necrosis, leucocyte infiltration and serum lipid peroxidation and a significant increase in serum paraoxonase and lactonase activities, it did not change these histopathologic or biochemical parameters in myocardial infarcted diabetic rats. CONCLUSION: Lipoic acid, at the dose of 10 mg/kg, is effective to prevent myocardial infarction in non-diabetic rats but it is insufficient in diabetic rats (Tab. 1, Fig. 2, Ref. 35).

Reduced monocyte adhesion to aortae of diabetic plasminogen activator inhibitor-1 knockout mice.

OBJECTIVE AND DESIGN: To determine the requirement of plasminogen activator inhibitor-1-knockout (PAI-1) for monocyte adhesion in animals and cells under diabetic conditions. METHODS AND SUBJECTS: Monocyte adhesion assay, enzyme-linked immunosorbent assay, and Western blotting were used in analyzing samples from PAI-1-knockout (PAI-1-KO) mice or cultured human umbilical vein endothelial cells (HUVEC). TREATMENTS: Diabetes in PAI-1-KO and wild-type mice was induced by intraperitoneal injection of streptozotocin (STZ). HUVEC was transfected with short interference RNA (siRNA) against PAI-1, tumor necrosis factor-α (TNFα), or toll-like receptor (TLR4), and then was treated with glycated low-density lipoproteins (glyLDL). RESULTS: The adhesion of monocytes to aortic intima was reduced in PAI-1-KO mice, which was associated with decreased levels of TNFα and monocyte chemotactic protein-1 (MCP-1) in plasma and cardiovascular tissue, and increased abundances of urokinase plasminogen activator (uPA) and uPA receptor (uPAR) in cardiovascular tissue compared to wild-type mice. Significant reductions in monocyte adhesion, inflammatory, and fibrinolytic regulators were detected in cardiovascular tissue or plasma in diabetic PAI-1-KO mice compared to wild-type diabetic mice. Transfection of PAI-1, TNFα or TLR4 siRNA to HUVEC inhibited glyLDL-induced monocyte adhesion to EC. PAI-1 siRNA inhibited the abundances of TLR4 and TNFα in EC. CONCLUSION: The findings suggest that PAI-1 is required for diabetes-induced monocyte adhesion via interactions with uPA/uPAR, and it also regulates TLR4 and TNFα expression in vascular EC. Inhibition of PAI-1 potentially reduces vascular inflammation under diabetic condition.

Changes in mitochondrial properties may contribute to enhanced resistance to ischemia-reperfusion injury in the diabetic rat heart.

Diabetes mellitus, besides having deleterious effects, induces cardiac adaptation that may reduce the heart's susceptibility to ischemia-reperfusion (IR) injury. This study aimed to investigate whether changes in mitochondrial properties are involved in the mechanisms of increased resistance of the diabetic heart to IR. Adult male Wistar rats were made diabetic by a single dose of streptozotocin (65 mg·kg-1, i.p.), and on the day 8, Langendorff-perfused hearts were subjected to 30 min global ischemia and 40 min reperfusion. Baseline preischemic parameters in the diabetic hearts did not differ markedly from those in the nondiabetic controls, except for lower left ventricular developed pressure, higher mitochondrial membrane fluidity, and protein levels of manganese superoxide dismutase. On the other hand, diabetic hearts showed significantly better post-IR functional restoration and reduced arrhythmogenesis associated with lower reactive oxygen species production as compared with healthy controls. IR decreased membrane fluidity in both experimental groups; however, it led to a complete recovery of mitochondrial Mg2+-ATPase activity in diabetics in contrast to its reduction in nondiabetics. These findings indicate that the heart may become adapted to diabetes-induced alterations that might increase its tolerance to an ischemic insult. Preserved mitochondrial function might play a role in the mechanisms of the heart's resistance to IR injury in diabetics.