STZ-diabetic Rats Research Articles

Flavonoid-rich fraction of Monodora tenuifolia Benth seeds improves antioxidant status in male Wistar rats with streptozotocin-induced Diabetes mellitus

BackgroundOxidative stress is a disruption in the balance between free radicals and the body's natural defenses. This study investigated the modulatory effect of a flavonoid-rich fraction of Monodora tenuifolia seed (FRFMTS) on oxidative stress and antioxidant enzymes in diabetic Wistar rats. The plant seeds were collected, and identified then, hydro-ethanolic extract was obtained with 80 % (v/v) ethanol and partitioned with solvents to obtain the FRFMTS. Diabetes mellitus was induced with a single dose of 40 mg/kg bwt streptozotocin and the rats were treated according to their grouping; group 1: non-diabetic control, groups 2 and 3: non-diabetic treated with 25 mg/kg FRFMTS and 50 mg/kg FRFMTS, respectively. Group 4: diabetic control group, groups 5 and 6: diabetic groups treated with 25 mg/kg and 50 mg/kg FRFMTS, respectively, while group 7: diabetic treated with 6.67 mg/kg metformin. Antioxidant status, oxidative stress biomarkers and activities of antioxidant enzymes were determined in plasma, heart, and kidney tissues using established procedures. ResultsPlasma total antioxidant status (TAS) was increased significantly (p < 0.05) in diabetic rats upon treatment with 25 mg/kg FRFMTS (70.4 %), while 50 mg/kg FRFMTS increased TAS by 70 %. The activities of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) in the plasma, heart, and kidney of diabetic rats significantly decreased (61.3 %, 58.8 % and 31.4 % respectively) while lipid peroxidation (LPO) was elevated when compared with normal control groups. Flavonoid-rich fraction of M. tenuifolia at 25 mg/kg bwt and 50 mg/kg bwt significantly increased the activity GPx enzyme by 32.3 % and 72 % in plasma, while there was no significant differences in both kidney and heart of diabetic rats when compared with diabetic control groups. The treatment of diabetic rats with 25 mg/kg FRFMTS and 50 mg/kg FRFMTS improved SOD activity in the plasma (51.5 % and 69.8 %), heart (32.3 % and 27.6 %) and kidney (31.4 % and 27.1 %) respectively, and CAT activity in plasma (44.2 % and 57 %), heart (28.6 % and 60 %) and kidney (69.6 % and 76.7 %) respectively. The concentration of malondialdehyde (MDA) in lipid peroxidation assay in the heart and kidney of diabetic rats treated with 25 mg/kg FRFMTS and 50 mg/kg FRFMTS reduced significantly by (62.5 % and 71.1 % in heart), while 50 mg/kg FRFMTS significantly reduced MDA in kidney by 43.8 %. ConclusionsThe results showed that FRFMTS reduces oxidative stress and enhances the activities of antioxidant enzymes in STZ-diabetic Wistar rats. As such, FRFMTS could be useful in the management of oxidative stress-mediated diabetic complications.

Prediction of Protein-Drug Interactions, Pharmacophore Modeling, and Toxicokinetics of Novel Leads for Type 2 Diabetes Treatment.

Small heterocyclic compounds have been crucial in pioneering advances in type 2 diabetes treatment. There has been a dramatic increase in the pharmacological development of novel heterocyclic derivatives aimed at stimulating the activation of Glucokinase (GK). A pharmaceutical intervention for diabetes is increasingly targeting GK as a legitimate target. Diabetes type 2 compromises Glucokinase's function, an enzyme vital for maintaining the balance of blood glucose levels. Medicinal substances strategically positioned to improve type 2 diabetes management are used to stimulate the GK enzyme using heterocyclic derivatives. The research endeavor aimed to craft novel compounds, drawing inspiration from the inherent coumarin nucleus found in nature. The goal was to evoke the activity of the glucokinase enzyme, offering a tailored approach to mitigate the undesired side effects typically associated with conventional therapies employed in the treatment of type 2 diabetes. Coumarin, sourced from nature's embrace, unfolds as a potent and naturally derived ally in the quest for innovative antidiabetic interventions. Coumarin was extracted from a variety of botanical origins, including Artemisia keiskeana, Mallotus resinosus, Jatropha integerrima, Ferula tingitana, Zanthoxylum schinifolium, Phebalium clavatum, and Mammea siamensis. This inclusive evaluation was conducted on Muybridge's digital database containing 53,000 hit compounds. The presence of the coumarin nucleus was found in 100 compounds, that were selected from this extensive repository. Utilizing Auto Dock Vina 1.5.6 and ChemBioDraw Ultra, structures generated through this process underwent docking analysis. Furthermore, these compounds were accurately predicted online log P using the Swiss ADME algorithm. A predictive analysis was conducted using PKCSM software on the primary compounds to assess potential toxicity. Using Auto Dock Vina 1.5.6, 100 coumarin derivatives were assessed for docking. Glucokinase (GK) binding was significantly enhanced by most of these compounds. Based on superior binding characteristics compared with Dorzagliatin (standard GKA) and MRK (co-crystallized ligand), the top eight molecules were identified. After further evaluation through ADMET analysis of these eight promising candidates, it was confirmed that they met the Lipinski rule of five and their pharmacokinetic profile was enhanced. The highest binding affinity was demonstrated by APV16 at -10.6 kcal/mol. A comparison between the APV16, Dorzagliatin and MRK in terms of toxicity predictions using PKCSM indicated that the former exhibited less skin sensitization, AMES toxicity, and hepatotoxicity. Glucokinase is most potently activated by 100 of the compound leads in the database of 53,000 compounds that contain the coumarin nucleus. APV12, with its high binding affinity, favorable ADMET (adjusted drug metabolic equivalents), minimal toxicity, and favorable pharmacokinetic profile warrants consideration for progress to in vitro testing. Nevertheless, to uncover potential therapeutic implications, particularly in the context of type 2 diabetes, thorough investigations and in-vivo evaluations are necessary for benchmarking before therapeutic use, especially experiments involving the STZ diabetic rat model.

Insulin Treatment Does Not Prevent EARLY Autonomic Cardiovascular and Diastolic Dysfunctions in Streptozotocin-Induced Diabetic Rats.

Recent studies have found increased cardiovascular mortality risk in patients with type 1 diabetes when compared to normoglycemic people, even when they were kept under good glycemic control. However, the mechanisms underlying this condition have yet to be fully understood. Using streptozotocin (STZ)-induced diabetic rats, we evaluated the effects of insulin replacement therapy on cardiac, autonomic, inflammatory, and oxidative stress parameters. Daily treatment with insulin administrated subcutaneously in the STZ-diabetic rats showed a reduction in hyperglycemia (>250 mg/dL) to normalized values. The insulin treatment was effective in preventing alterations in cardiac morphometry and systolic function but had no impact on diastolic function. Also, the treatment was not able to prevent the impairment of baroreflex-tachycardic response and systolic arterial pressure variability (SAP-V). A correlation was found between improvement of these autonomic parameters and higher levels of IL-10 and lower levels of oxidized glutathione. Our findings show that insulin treatment was not able to prevent diastolic, baroreflex, and SAP-V dysfunction, suggesting an outstanding cardiovascular risk, even after obtaining a good glycemic control in STZ-induced diabetic rats. This study shed light on a relatively large population of diabetic patients in need of other therapies to be used in combination with insulin treatment and thus more effectively manage cardiovascular risk.

Phloretamide Protects against Diabetic Kidney Damage and Dysfunction in Diabetic Rats by Attenuating Hyperglycemia and Hyperlipidemia, Suppressing NF-κβ, and Upregulating Nrf2.

Potent hypoglycemic and antioxidant effects were recently reported for the apple-derived phenolic compound phloretamide (PLTM). The renoprotective effects of this compound are yet to be shown. This study aimed to examine the potential of PLTM to prevent diabetic nephropathy in streptozotocin-induced diabetic rats and to examine the possible mechanisms of protection. Non-diabetic and STZ-diabetic male rats were treated orally by gavage with either the vehicle or with PTLM (200 mg/kg; twice/week) for 12 weeks. PTLM significantly increased urine volume and prevented glomerular and tubular damage and vacuolization in STZ-diabetic rats. It also increased creatinine excretion and reduced urinary albumin levels and the renal levels of kidney injury molecule-1 (KIM-1), 8-hydroxy-2'-deoxyguanosine (8-OHdG), neutrophil gelatinase-associated lipocalin (NGAL), and nephrin in the diabetic rats. PTLM also prevented an increase in the nuclear levels of NF-κβ, as well as the total levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), caspase-3, and Bax in the kidneys of diabetic rats. These effects were associated with reduced serum levels of triglycerides, cholesterol, and low-density lipoprotein cholesterol. In both the control and diabetic rats, PTLM significantly reduced fasting plasma glucose and enhanced the renal mRNA and cytoplasmic levels of Nrf2, as well as the levels of Bcl2, superoxide dismutase (SOD), and glutathione (GSH). However, PTLM failed to alter the cytoplasmic levels of keap1 in diabetic rats. In conclusion, PTLM prevents renal damage and dysfunction in STZ-diabetic rats through its hypoglycemic and hypolipidemic activities, as well as through its antioxidant potential, which is mediated by activating the Nrf2/antioxidant axis.

Lipid nanoparticles of quercetin (QU-Lip) alleviated pancreatic microenvironment in diabetic male rats: The interplay between oxidative stress – unfolded protein response (UPR) – autophagy, and their regulatory miRNA

BackgroundAutophagy is a well-preserved mechanism essential in minimizing endoplasmic reticulum stress (ER)-related cell death. Defects in β-cell autophagy have been linked to type 1 diabetes, particularly deficits in the secretion of insulin, boosting ER stress sensitivity and possibly promoting pancreatic β-cell death. Quercetin (QU) is a potent antioxidant and anti-diabetic flavonoid with low bioavailability, and the precise mechanism of its anti-diabetic activity is still unknown.AimThis study aimed to design an improved bioavailable form of QU (liposomes) and examine the impact of its treatment on the alleviation of type 1 diabetes induced by STZ in rats. MethodsSeventy SD rats were allocated into seven equal groups 10 rats of each: control, STZ, STZ + 3-MA, STZ + QU-Lip, and STZ + 3-MA + QU-Lip. Fasting blood glucose, insulin, c-peptide, serum IL-6, TNF-α, pancreatic oxidative stress, TRAF-6, autophagy, endoplasmic reticulum stress (ER stress) markers expression and their regulatory microRNA (miRNA) were performed. As well as, docking analysis for the quercetin, ER stress, and autophagy were done. Finally, the histopathological and immunohistochemical analysis were conducted. SignificanceQU-Lip significantly decreased glucose levels, oxidative, and inflammatory markers in the pancreas. It also significantly downregulated the expression of ER stress and upregulated autophagic-related markers. Furthermore, QU-Lip significantly ameliorated the expression of several MicroRNAs, which both control autophagy and ER stress signaling pathways. However, the improvement of STZ-diabetic rats was abolished upon combination with an autophagy inhibitor (3-MA). The findings suggest that QU-Lip has therapeutic promise in treating type 1 diabetes by modulating ER stress and autophagy via an epigenetic mechanism.

Reduced Progression of Diabetic Nephropathy in Streptozocin-Induced Diabetic rats by Lannea coromandelica Leaf Extract

Objectives: An important contributor to end-stage renal failure globally is diabetic kidney disease. The current study looked at the safeguarding results of an infusion of Ethanol from Lannea coromandelica houtt leaves (ELCL)in diabetic kidney disease that was caused by streptozotocin with the intention to treat diabetic nephropathy, creating supportive and substitute medicine is necessary. The development of DN may be slowed down by itsanti-inflammatory, anti-diabetic and antioxidant qualities. The novelity lies in the plant selection for the study. Methods: Streptozotocin (45mg/kg, i.p.) was administered as a single dosage to rats to induce diabetes. During 8 weeks, oral dosages of ELCL (100mg/kg and 200mg/kg.) were given to rodents with STZ diabetes. Blood sugar amounts and body and kidney weights were measured at the conclusion of the trial period. The parameters of serum and urine were evaluated. The kidney levels of lipid peroxide and antioxidant enzymes were assessed. Results: In STZ-diabetic rats and rats treated with extract, ethylacetate extract dramatically raised body weight and decreased blood glucose, blood urea levels, blood nitrogen levels, and the creatinine levels. All kidney antioxidants, including glutathione synthetase, glutathione-S-transferase, catalase, superoxide dismutase and NAD(P) H dehydrogenase [quinone]1 were highly upregulated by the extract. Conclusion: According to research, ELCL may have antioxidant, antihyperglycemic, and anti-glycation properties that could slow the progression of diabetic nephropathy.

Atorvastatin increases autophagic flux and p62/SQSTM1 of kidney cells in hyperglycemic conditions and treatment in combination with insulin improves renal function of streptozotocin (STZ)-induced diabetic rats

Background: Although atorvastatin is commonly used as a hypolipidemic agent, it confers many health benefits in which the underlying mechanisms are not fully understood. We have previously shown that combined treatment of atorvastatin and insulin effectively restored renal function of streptozotocin (STZ)-induced diabetic rats; nevertheless, the underlying mechanism was not known. Objective: To determine whether the reno-protective effect of atorvastatin and insulin is mediated through its impact on autophagy. Materials and methods: Markers of autophagy, LC3, and p62/SQSTM1, in rat kidney tissues and cell lines treated with atorvastatin and/or insulin were determined by Western blot analysis. Results: Levels of both LC3-I and LC3-II proteins in kidney tissues of STZ-diabetic rats treated with atorvastatin and insulin were significantly increased. The autophagic flux was examined in vitro and showed that high glucose culture conditions suppressed the autophagic flux in kidney cells. Treatment with insulin moderately increased the conversion of LC3-I to LC3-II. Interestingly, atorvastatin increased autophagic flux only in the hyperglycemic but not in the normoglycemic condition. p62/SQSTM1 protein level was decreased in response to high glucose treatment but increased with the addition of insulin and/or atorvastatin. Conclusion: This study has demonstrated that atorvastatin may represent a novel regimen in providing prevention and protection for diabetic nephropathy through the underlying mechanisms of inducing autophagy and p62/SQSTM1.

Therapeutic Effects of Nigella sativa Oil and Whole Seeds on STZ-Induced Diabetic Rats: A Biochemical and Immunohistochemical Study.

Type II diabetes mellitus (DM) is an increasing health problem that has negative impacts on patients and healthcare systems, worldwide. The development of new therapies with better efficacy, fewer side effects, and lower prices are urgently needed to treat this disease. To evaluate and compare the therapeutic effects of Nigella sativa (N. sativa) seed and oil on the biochemical parameters and regeneration of pancreatic islets (or islets of Langerhans) of streptozotocin (STZ)-induced diabetic rats. The diabetic rat model was prepared by administering a single dose of STZ (35 mg/kg body weight). The whole seed or the oil of N. sativa was administered to the diabetic and control groups for a period of 28 days, but not to the negative and STZ controls. Serum blood glucose, liver enzymes, lipid profile, and renal function tests (uric acid, albumin, total protein, urea, and creatinine) were measured in all groups. After the rats were euthanized, their pancreases were extracted, and then sectioned and fixed on slides in preparation before staining with H&E stain and immunohistochemical study. Treatment of STZ-diabetic rats with N. sativa seeds or oil significantly improved their serum glucose levels, lipid profiles, and liver and renal functions as well as preserved the integrity of pancreatic β cells. N. sativa seeds and oil demonstrate significant therapeutic improvement effects on DM and its related complications including effective protection of islets of Langerhans. The therapeutic benefits of N. sativa seeds and oil on DM and its related complications are comparable.

Effect of Reboxetine Treatment on BDNF, Synaptophysin, and PSD-95 Levels in the Spinal Dorsal Horn of Rats with Diabetic Neuropathy

Objective: It is known that neuropathic pain is accompanied by alterations in the levels of neurotrophic factors and synaptic proteins in the microenvironment of the spinal dorsal horn. Such changes contribute to hyperalgesia and allodynia processes; thus, analgesic drugs can exert their pharmacological effects by affecting the expressions, levels, or functions of these endogenous substances. In this study, based on the knowledge that reboxetine (a selective noradrenaline reuptake inhibitor) has the potential for antihyperalgesic efficacy in diabetic neuropathy, we aimed to examine the probable effects of this drug on diabetes-induced changes in brain-derived neurotrophic factor (BDNF), synaptophysin (the pre-synaptic marker of synaptic integration), and postsynaptic density-95 (PSD-95) (the postsynaptic marker of synaptic integration) levels in the superficial laminae of the dorsal horn. &#x0D; Methods: Experimental diabetes was induced by a single-dose injection of streptozotocin (STZ) (50 mg/kg) in rats. After four week-long induction period of painful diabetic neuropathy, rats were treated orally with 8 mg/kg reboxetine for two weeks. Hyperalgesia responses were evaluated by using the Randall–Selitto and Hargreave's tests. Following the pain tests, immunohistochemical studies were performed.&#x0D; Results: Two weeks of reboxetine administration increased the reduced paw withdrawal thresholds and shortened the paw withdrawal latencies of diabetic rats in neuropathic pain tests, indicating the antihyperalgesic efficacy of this drug. Moreover, augmented BDNF and synaptophysin levels in diabetic rats reversed by reboxetine treatment. However, there was no alteration in the densities of PSD-95, in both STZ-diabetic and reboxetine-treated STZ-diabetic rats. &#x0D; Conclusion: The obtained results suggested that inhibition of central sensitization and modulation of spinal plasticity seem to be pharmacological mechanisms underlying reboxetine's antihyperalgesic effects on diabetic rats. However, further studies are still needed to clarify the exact mechanism of action.

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker on oxidative stress and metabolism of elements in kidney of STZ-induced diabetic rats

In diabetes, increased oxidative stress and impaired trace element metabolism play an important role in the pathogenesis of diabetic nephropathy. The objective of this research was to examine the outcomes of blocking the renin-angiotensin system, using either the angiotensin-converting enzyme inhibitor (ACEI), perindopril, or the angiotensin II type 1 (AT1) receptor blocker, irbesartan, on oxidative stress and trace element levels such as Zn, Mg, Cu, and Fe in the kidneys of diabetic rats that had been induced with streptozotocin.Thirty-two Wistar albino male rats were equally divided into four groups. The first group was used as a control. The second group of rats developed diabetes after receiving a single intraperitoneal dose of STZ. The third and fourth groups of rats had STZ-induced diabetes and received daily dosages of irbesartan (15 mg/kg b.w/day) and perindopril (6 mg/kg b.w/day) treatment, respectively.Biochemical analysis of the kidneys showed a distinct increase in oxidative stress, indicated by heightened levels of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activities, as well as reduced glutathione (GSH) levels in the kidneys of diabetic rats. In the kidneys of diabetic rats, the mean levels of Fe and Cu were found to be significantly higher than those of the control group. Additionally, the mean levels of Zn and Mg were significantly lower in the diabetic rats compared to the control rats. Both perindopril and irbesartan decreased significantly MDA content and increased SOD activities and GSH levels in the kidneys of rats with diabetes. The Zn and Mg concentrations in the kidneys of diabetic rats treated with perindopril and irbesartan were markedly higher than in untreated STZ-diabetic rats, while the Cu and Fe concentrations were significantly lower. The urinary excretion of rats treated with perindopril and irbesartan showed a pronounced increase in Cu levels, along with a significant reduction in Zn and Mg levels. Although diabetic rats demonstrated degenerative morphological alterations in their kidneys, both therapies also improved diabetes-induced histopathological modifications in the kidneys.Finally, the present results suggest that manipulating the levels of Zn, Mg, Cu, and Fe - either through ACE inhibition or by blocking AT1 receptors - could be advantageous in reducing lipid peroxidation and increasing antioxidant concentration in the kidneys of diabetic rats.

Potential roles of circulating microRNAs in the healing of type 1 diabetic wounds treated with green tea extract: molecular and biochemical study

BackgroundCirculating miRNAs have been implicated in various aspects of diabetic wound healing, including inflammation, angiogenesis, and extracellular matrix remodeling. Thus, in alternative herbal medicine strategies, miRNAs will be potential therapeutic molecular targets in nonhealing wounds. These could be valuable elements for understanding the molecular basis of diabetic wound healing and could be used as good elements in bioinformatics. ObjectivesTo elucidate the molecular mechanisms of microRNAs in association with apoptosis-inducing genes in controlling skin wound healing in diabetic wounds treated with green tea polyphenols (GTPs). MethodsGreen tea hydro extract (GTE) at doses of100–200 mg/ml was topically applied to the skin tissues of rats with T1DM induced by a single dose of streptozotocin (STZ; 100 mg/kg, in 0.01 M sodium citrate, pH 4.3–4.5) injected intraperitoneally for seven consecutive days to induce T1DM. The rats were treated with green tea for three weeks. A sterile surgical blade was used to inflict a circular wound approximately 2 cm in diameter on the anterior-dorsal side of previously anesthetized rats by a combination of ketamine hydrochloride (50 mg/kg, i.e., body weight) and xylazine hydrochloride. Afterward, the molecular roles of the circulating miRNAs miR-21, miR-23a, miR-146a, and miR-29b and apoptotic genes were determined by quantitative real-time PCR to evaluate Bax, Caspase-3, and Bcl-2 in wound healing. In addition, HPLC analysis was also performed to estimate the active polyphenols (GTPs) present in the hydro extract of green tea leaves. ResultsWound healing was improved in diabetic skin wounds following treatment with GTE at doses of 100–200 mg/dl for three weeks. The wound parameters contraction, epithelialization, and scar formation significantly improved in a short time (14 days) compared to the longer periods identified in diabetic non-treated rats (20 days) and the standard control (15.5 days). Molecular analyses reported a significant increase in the levels of miR-21, miR-23a, and miR-146a and a decrease in the levels of miR-29b in green tea-treated diabetic rats compared to those in the standard control and STZ-diabetic non-treated rats. In addition, the molecular apoptotic genes Bax and caspase-3 significantly increased, and the BcL-2 gene significantly decreased following treatment with green tea polyphenols. ConclusionsThe data showed that active green tea polyphenols (GTPs) present in GTE significantly improved diabetic wound healing by controlling apoptotic genes and the circulating microRNAs miR-21, miR-23a, miR-146a, and miR-29b, which might be involved in cellular apoptosis and angiogenesis processes. Thus, to establish a future model for the treatment of diabetic wounds, further studies are needed to understand the potential association of these biological parameters with the wound-healing process in diabetic wounds.

Protective Effects of Ginger Extract on Oxidative Stress and Steroidogenesis-related Genes in The Ovary of Streptozotocin-induced Diabetic Rats

Background and Aims: Ginger has anti-oxidant and anti-diabetic properties, but its beneficial effects have not been fully understood on ovarian disorders in diabetic conditions. In the current project, the impact of ginger extract was investigated on oxidative stress and steroidogenesis-related genes in streptozotocin (STZ)-induced female rats. &#x0D; Materials and Methods: The STZ-induced rats were utilized as a diabetic model and received 200 or 400 mg/kg/day ginger extract for eight weeks. The biochemical factors were measured by standard procedures in this study. Serum levels of insulin and sex hormones were assessed by the enzyme-linked immunosorbent assay (ELISA) technique, and the mRNA expression of target genes was assayed by real-time polymerase chain reaction.&#x0D; Results: An increase in the levels of glucose, testosterone, and malondialdehyde (MDA) as well as a decrease in the levels of insulin, glutathione peroxidase (GPx), 3β-hydroxysteroid dehydrogenase (3βHSD), steroidogenic acute regulatory protein (StAR), 17β-estradiol, and progesterone was observed in the diabetic rats. Ginger (200 mg/kg) exhibited a significant amelioration in the levels of glucose, testosterone, and MDA. Treatment with 200 mg/kg ginger enhanced the levels of GPx, StAR, and 17β-estradiol. Administration with 400 mg/kg ginger extract also ameliorated the level of glucose, testosterone, MDA, and elevated the level of insulin, GPx, 3βHSD, StAR, 17β-estradiol, and progesterone in the diabetic rats.&#x0D; Conclusion: The current study suggests ginger extract protects against ovarian damage in STZ-diabetic rats.

Effects of Kudzu Root on Oxidative Stress and Inflammation in Streptozotocin-induced Diabetic Rats

Background: Oxidative stress and inflammation are strictly connected, and both perform an important role in the pathogenesis of diabetes mellitus (DM). Objectives: This research aimed to investigate the potential protective effect of kudzu root against oxidative stress and inflammation in a streptozotocin (STZ)-induced DM animal model. Methods: DM was induced in male Wistar rats by intraperitoneal injection of STZ (50 mg/kg body weight). The kudzu root (100 mg/kg BW) was administered orally after 1 week of STZ administration in diabetic animals (for 6 weeks). Results: The diabetic animals exhibited a significant increase in fasting blood glucose, tumor necrosis factor-alpha, and malondialdehyde levels. However, they exhibited a significant decrease in plasma insulin level, superoxide dismutase, and glutathione peroxidase activity. Administration of kudzu root to diabetic animals reversed these effects. Conclusion: The current study indicated that kudzu root has potent antidiabetic properties, likely through its anti-inflammatory and anti-oxidative properties in the STZ-diabetic rat model.

Non-reducing End of Heparin Tri-saccharide is a Scavenger Tool to Detoxify the Glucose Toxicity in Diabetes.

Heparin is a highly sulfated, hence highly polyanionic, glycosaminoglycan with a repeating disaccharide that contains a hexuronic acid, and it has been used as an anticoagulant clinically for more than half a century. Daily IP injections of small amounts of heparin in the STZ diabetic rat prevented these pathological responses even though the animals sustained hyperglycemic levels of glucose throughout. However, the structural determinant that mediates this activity is not clear. This paper describes our finding that the responses of hyperglycemic dividing mesangial cells to heparin are mediated by its non-reducing terminal trisaccharide and proposes that the non-reducing end tri-saccharide of heparin acts as a scavenger tool to detoxify the glucose toxicity in diabetes.

Improvement of microvascular complications in STZ-diabetic rats treated with Pterocarpus erinaceus Poir. extract

Pterocarpus erinaceus Poir. from Fabaceae family is a medicinal plant traditionally used in decoction or infusion to treat diabetes mellitus. Although this plant is used in treating diabetes, studies on the effectiveness of its stem bark on the complications induced by chronic hyperglycemia have not been thoroughly addressed. Thus, this study was conducted to prove the efficacy of hydroethanolic extract of stem bark of P. erinaceus on type 2 diabetes and its complications, such as renal fibrosis and retinopathy in rats. STZ diabetics. The dry extract of P. erinaceus stem bark was obtained following the hydroethanolic extraction (v/v). Diabetes was induced with streptozocin in SD rats pretreated with fructose-lard for 20 days. Then, the serum and urinary biochemical parameters were evaluated at the start and the end of the treatment. Rats with blood glucose ≥350 mg/dL and significant proteinuria were selected and treated with P. erinaceus stem bark extract and glibenclamide for 3 weeks. A complete blood count and a histopathological examination of the retina and kidneys were performed at the end of the 41st day of treatment. The results showed that P. erinaceus extract at a dose of 500 mg/kg bw and glibenclamide at a dose of 0.6 mg/kg bw caused a significant decrease (p < 0.0001) in basal blood glucose in STZ diabetic rats during treatment and improved oral glucose intolerance. At the end of the experiment, the treated rats showed a normalization in body weight, food and water consumption. Evaluating of biochemical parameters showed a significant (p < 0.001) decrease in total cholesterol, LDL-C, triglycerides, TG/HDL-C ratio, CPK and oxidative stress in treated rats. No retinal and kidney abnormalities were observed on histological sections in rats treated with plant extract and glibenclamide. In contrast, macular edema and renal fibrosis were observed in the diabetic control group. The findings showed that extract at a dose of 500 mg/kg bw improves oral glucose intolerance, and inhibits lipid deposition and retinal and renal fibrosis. Therefore, the plant extract could be exploited in the production of herbal medicines to manage diabetes and its complications.

Glyceamic Modulatory Effects of a Recipe from Some Commonly Consumed Fruit Pulps in Normal and Streptozotocin-induced Diabetic Rats

Plants continue to play an important role in the treatment and management of many diseases, including diabetes mellitus, in many developing economies. Most often, a cocktail of plant mixtures is normally used in traditional practice rather than single plant, which are believed to offer more benefits. Adansonia digitata, Hyphaene thebaica, Ziziphus spina-christi, and Ziziphus mauritiana are some of those plants that are reported to have medicinal benefits and, most importantly, anti-diabetic activity. This study evaluated the hypoglyceamic and antidiabetic activity of the aqueous extracts of the fruit pulps and a recipe combining all the fruits in experimental rats. Aqueous extracts of the different fruits and the recipe were orally administered to normoglyceamic and Streptozotocin (STZ)-induced diabetic rats, and their blood glucose was monitored over a period of 3 hours in the screening study. Two different doses of the recipe were also administered daily for four (4) weeks to STZ-diabetic rats to study the antidiabetic potential of the recipe. All the extracts did not significantly reduce the fasting blood glucose (FBG) of the normoglyceamic rats in the hypoglyceamic screening study. In the antidiabetic screening study, all the extracts lowered the FBG of their respective groups with percent reductions of 32%, 21%, 17%, and 46%, respectively, for Z. spina-christi, Z. mauritiana, A. digitata and H. thebaica extractives. The maximum percent reduction observed for the recipe was 25.5%. The daily administration of the recipe for four weeks also produced significant reductions that were not dose dependent. The 200 mg/kg bd. wt. dose showed a maximum reduction of 59.9%. The percentage reductions observed in the recipe-treated group were, however, lower than the percentage reductions seen in the insulin and glibenclamide-treated groups. The study confirms the antidiabetic properties of the individual fruits and the recipe, and thus confirms the traditional use of the fruits in the management of diabetes mellitus.

Antioxidant Activity and Protective Effects of an Oxovanadium (IV) Complex on Heart and Aorta Injury of STZ-Diabetic Rats.

Diabetic people have a much higher rate of cardiovascular disease than healthy people. Therefore, heart and aortic tissues are target tissues in diabetic research. In recent years, the synthesis of new vanadium complexes and investigation of their antidiabetic/lowering effect on the blood glucose levels and antioxidant properties are increasing day by day. Our study aimed to examine the effects of synthesized oxovanadium (IV) complex of 2-[(2,4-dihydroxybenzylidene]hydrazine-1-[(N-(2-hydroxybenzylidene)](S-methyl)carbothioamide [VOL] on diabetic heart and aortic tissues, as well as in vitro lactate dehydrogenase (LDH) and myeloperoxidase (MPO) inhibition, antioxidant properties, and reducing power. Electrochemical characterization of the VOL was carried out by using Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV) methods. In addition, in silico drug-likeness and ADME prediction were also investigated. For in vivo study, male Swiss albino rats were randomly selected and separated into four groups which are control, control + VOL, diabetic and diabetic + VOL. After the experimental procedure, biochemical parameters were investigated in homogenates of heart and aorta tissues. The results showed that VOL has a protective effect on heart and aortic tissue against oxidative stress. According to electrochemical experiments, one reversible oxidative couple and one irreversible reductive response were observed for the complex. In addition, in vitro LDH and MPO inhibition of VOL was examined. It was found that VOL had a protective effect on heart and aortic tissues of diabetic rats, and caused the inhibition of LDH and MPO in in vitro studies. On the other hand, evaluating the synthesized VOL according to in silico drug-likeness and absorption, distribution, metabolism, and excretion (ADME) prediction, it was found that VOL has drug-like properties and exhibited high gastrointestinal absorption. The VOL had a therapeutic impact on the heart and aortic tissues of diabetic rats, according to the findings.

The effect of GLP-1 receptor agonist lixisenatide on experimental diabetic retinopathy.

Glucagon-like peptide-1 receptor agonists are effective treatments for type 2 diabetes, effectively lowering glucose without weight gain and with low risk for hypoglycemia. However, their influence on the retinal neurovascular unit remains unclear. In this study, we analyzed the effects of the GLP-1 RA lixisenatide on diabetic retinopathy. Vasculo- and neuroprotective effects were assessed in experimental diabetic retinopathy and high glucose-cultivated C. elegans, respectively. In STZ-diabetic Wistar rats, acellular capillaries and pericytes (quantitative retinal morphometry), neuroretinal function (mfERG), macroglia (GFAP western blot) and microglia (immunohistochemistry) quantification, methylglyoxal (LC-MS/MS) and retinal gene expressions (RNA-sequencing) were determined. The antioxidant properties of lixisenatide were tested in C. elegans. Lixisenatide had no effect on glucose metabolism. Lixisenatide preserved the retinal vasculature and neuroretinal function. The macro- and microglial activation was mitigated. Lixisenatide normalized some gene expression changes in diabetic animals to control levels. Ets2 was identified as a regulator of inflammatory genes. In C. elegans, lixisenatide showed the antioxidative property. Our data suggest that lixisenatide has a protective effect on the diabetic retina, most likely due to a combination of neuroprotective, anti-inflammatory and antioxidative effects of lixisenatide on the neurovascular unit.

Isosteviol attenuates streptozotocin-mediated diabetic nephropathy in rats by upregulating and stimulating adenosine monophosphate-activated protein kinase.

Diabetic nephropathy (DN) is the major microvascular complication of type 1 diabetes mellitus (T1DM). Impairment in adenosine monophosphate-activated protein kinase (AMPK) activity was shown to mediate the pro-oxidant and inflammatory mechanisms underlying DN. Isosteviol (ISV), isolated from Stevia rebaudiana, has antioxidant and anti-inflammatory properties and alleviates non-alcoholic fatty liver disease and lethal septic shock by activating AMPK. The effect of ISV on DN is unknown. This study examined if ISV alleviates DN in T1DM in adult male rats by activating AMPK. Diabetes was induced in rats by a single intraperitoneal (i.p.) injection of streptozotocin (STZ) (65 mg/kg). Five groups of rats (n=8 each) were designed and included: control, ISV (20 mg/kg orally), STZ (diabetic), STZ + ISV (20 mg/kg orally), STZ + ISV + CC (compound C/an AMPK inhibitor) (0.2 mg/kg, i.p). Fasting glucose and insulin levels, assessment of kidney function tests, lipid profile analysis, measurements of markers of oxidative stress and inflammation, PCR and Western blotting analysis, and histological studies of the kidneys were conducted. With no effect on fasting glucose or insulin levels (p>0.05), ISV reduced serum levels of cholesterol, triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-c) (p<0.01). ISV also increased urinary creatinine excretion, reduced urinary albumin levels, and alleviated tubular and glomerular damage of STZ-diabetic kidneys. ISV also lowered the renal levels of malondialdehyde (MDA) (p<0.01), tumor necrosis factor-alpha (TNF-α) (p<0.01), interleukin-6 (IL-6) (p<0.01), and mRNA and nuclear protein levels of nuclear factor kappaB (NF-κB) in both the control and diabetic rats. Concomitantly, ISV increased the phosphorylation of AMPK (p<0.05), levels of superoxide dismutase (SOD) (p<0.01), catalase (CAT) (p<0.01), total glutathione (GSH) (p<0.01), and mRNA and nuclear protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) (p<0.01) in the kidneys of the control and diabetic rats. Co-administration of CC prevented all renal protective effects of ISV and reversed all these effects. In conclusion, AMPK-induced inhibition of NF-κB and activation of Nrf2 entails the nephroprotective effect of ISV in STZ-diabetic rats.

Pharmacological Interaction Between Cannabidiol and Tramadol on Experimental Diabetic Neuropathic Pain: An Isobolographic Analysis.

Introduction: Diabetic neuropathies are the most prevalent chronic complications of diabetes, characterized by pain and substantial morbidity. Although many drugs have been approved for the treatment of this type of pain, including gabapentin, tramadol (TMD), and classical opioids, it is common to report short-term results or potentially severe side effects. TMD, recommended as a second-line treatment can lead to unwanted side effects. Cannabidiol (CBD) has been gaining attention recently due to its therapeutic properties, including pain management. This study aimed to characterize the pharmacological interaction between CBD and TMD over the mechanical allodynia associated with experimental diabetes using isobolographic analysis. Materials and Methods: After diabetes induction by streptozotocin (STZ), diabetic rats were systemically treated with CBD or TMD alone or in combination (doses calculated based on linear regression of effective dose 40% [ED40]) and had the mechanical threshold evaluated using the electronic Von Frey apparatus. Both experimental and theoretical additive ED40 values (Zmix and Zadd, respectively) were determined for the combination of CBD plus TMD in this model. Results: Acute treatment with CBD (3 or 10 mg/kg) or TMD (2.5, 5, 10, or 20 mg/kg) alone or in combination (0.38+1.65 or 1.14+4.95 mg/kg) significantly improved the mechanical allodynia in STZ-diabetic rats. Isobolographic analysis revealed that experimental ED40 of the combination (Zmix) was 1.9 mg/kg (95% confidence interval [CI]=1.2-2.9) and did not differ from the theoretical additive ED40 2.0 mg/kg (95% CI=1.5-2.8; Zadd), suggesting an additive antinociceptive effect in this model. Conclusions: Using an isobolographic analysis, these results provide evidence of additive pharmacological interaction between CBD and TMD over the neuropathic pain associated with experimental diabetes induced by STZ.