Brain Tissue Of Diabetic Rats Research Articles

Empagliflozin alleviates diabetes-induced cognitive impairments by lowering nicotinamide adenine dinucleotide phosphate oxidase-4 expression and potentiating the antioxidant defense system in brain tissue of diabetic rats

BackgroundDiabetes-induced cognitive impairment is a major challenge in patients with uncontrolled diabetes mellitus. It has a complicated pathophysiology, but the role of oxidative stress is central. Therefore, the use of antidiabetic drugs with extra-glycemic effects that reduce oxidative damage may be a promising treatment option. MethodsMale Wistar rats were randomly divided into four groups as normal, normal treated, diabetic and diabetic treated (n = 8 per group). Type 1 diabetes was induced by a single intraperitoneal dose of streptozotocin (STZ) (40 mg/kg). Two treatment groups received empagliflozin for 5 weeks (20 mg/kg/po). Cognitive ability was evaluated using open field, Elevated Plus Maze (EPM) and the Morris Water Maze (MWM) tests at study completion. Blood and brain tissue samples were collected - and analysis for malondialdehyde (MDA) and glutathione (GLT) content and catalase (CAT) and superoxide dismutase (SOD) enzyme activity were performed. Additionally, expression of nicotinamide adenine dinucleotide phosphate oxidase-4 (Nox-4) enzyme in brain tissue was analyzed using RT-PCR. ResultsSTZ increased blood glucose and induced diabetes with oxidative stress by lowering the antioxidant system potency and increasing Nox-4 expression after 5-weeks in brain tissue accompanied by reduction in cognitive performance. Also, diabetes induced anxiety-like behavior and impaired spatial memory in MWM, EPM and open field tests. However, empagliflozin reversed these changes, improving SOD and CAT activity, GLT content and reducing Nox-4 expression and MDA concentration in brain tissue while improving cognitive ability. It reduced anxiety and depression-related activities. It also improved spatial memory in MWM test. ConclusionUncontrolled diabetes negatively impacts mental function and impairs learning and cognitive performance via oxidative stress induction, the Nox-4 enzyme playing a central role. Empagliflozin reverses these effects, improving cognitive ability via promoting the anti-oxidative system and damping Nox-4 free radical generator enzyme expression. Therefore, empagliflozin is a promising treatment, providing both antidiabetic and extra-glycemic benefits for improving brain function in the diabetic milieu.

Protective effect of lactoferrin administration against brain tissue damage in diabetic rats

Bovine lactoferrin (bLf), a glycoprotein with iron, Several of Lf's functions intervene through various cell receptors. Its antibacterial, antiparasitic, anti-inflammatory, and antioxidant effects Additionally, it has been found that Lf has immunomodulating. We looked into the protective effects of Lf on various brain tissue indicators and histopathological examination of streptozotocin (STZ) induced diabetic rats. This research aimed to check the potential protective effect of lactoferrin verses brain lesion in STZ induced diabetic rat. The rats were split into five groups: Control (C), Diabetic rat (T2D), T2D + Insulin, T2D + Lactoferrin, and T2D + Insulin + Lactoferrin. Diabetes was created in rat groups by administration STZ (60 mg/kg body weight), then rat was sacrificed. The tissues of the Brain and serum had been chosen to analyze biochemical brain tissue indicators, Serum Neuron-Specific Enolase (SNE), Serum Brain-Derived Neurotrophic Factor (BDNF), and Tissue Necrosis Factor-Alpha (TNF-Alpha). Also, H&E staining was utilized to measure the histological changes of the brain and Comet assay of brain tissue samples for detection of DNA damage. In T2D rat, Lactoferrin corrected aberrant serum levels of SNE, BDNF and TNF-Alpha, in addition, Lactoferrin improves brain pathological changes might be through hypoglycemic, and/or anti-inflammatory actions and reduced DNA damage as compared to diabetic untreated rats. It could be concluded that oral administration of lactoferrin to diabetic rats alone or in combination with insulin treatment for six weeks was found to attenuate the harmful effects of diabetes on brain biomarkers as well as the pathological lesions that occur in the brain tissues of diabetic rats.

Securidaca inappendiculata Polyphenol Rich Extract Counteracts Cognitive Deficits, Neuropathy, Neuroinflammation and Oxidative Stress in Diabetic Encephalopathic Rats via p38 MAPK/Nrf2/HO-1 Pathways.

Diabetic encephalopathy is one of the serious emerging complication of diabetes. Securidaca inappendiculata is an important medicinal plant with excellent antioxidant and anti-inflammatory properties. This study investigated the neuroprotective effects of S. inappendiculata polyphenol rich extract (SiPE) against diabetic encephalopathy in rats and elucidated the potential mechanisms of action. Type 2 diabetes mellitus (T2DM) was induced using high fructose solution/intraperitoneal injection of streptozotocin and the diabetic rats were treated with SiPE (50, 100 and 200 mg/kg) for 8 weeks. Learning and memory functions were assessed using the Morris water and Y maze tests, depressive behaviour was evaluated using forced swimming and open field tests, while neuropathic pain assessment was assessed using hot plate, tail immersion and formalin tests. After the experiments, acetylcholinesterase (AChE), oxidative stress biomarkers and proinflammatory cytokines, caspase-3 and nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) were determined by ELISA kits. In addition, the expression levels of p38, phospho-p38 (p-p38), nuclear factor erythroid 2–related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined by western blot analyses. The results indicated that SiPE administration significantly lowered blood glucose level, attenuated body weight loss, thermal/chemical hyperalgesia, improved behavioural deficit in the Morris water maze, Y maze test and reduced depressive-like behaviours. Furthermore, SiPE reduced AChE, caspase-3, NF-κB, malonaldehyde malondialdehyde levels and simultaneously increased antioxidant enzymes activity in the brain tissues of diabetic rats. SiPE administration also significantly suppressed p38 MAPK pathway and upregulated the Nrf2 pathway. The findings suggested that SiPE exerted antidiabetic encephalopathy effects via modulation of oxidative stress and inflammation.

Oxymatrine Ameliorates Memory Impairment in Diabetic Rats by Regulating Oxidative Stress and Apoptosis: Involvement of NOX2/NOX4.

Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait and has been shown to exhibit a diverse range of pharmacological properties. The aim of the present study was to investigate the role of OMT in diabetic brain injury in vivo and in vitro. Diabetic rats were induced by intraperitoneal injection of a single dose of 65 mg/kg streptozotocin (STZ) and fed a high-fat and high-cholesterol diet. Memory function was assessed using a Morris water maze test. A SH-SY5Y cell injury model was induced by incubation with glucose (30 mM/l) to simulate damage in vitro. The serum fasting blood glucose, insulin, serum S100B, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were analyzed using commercial kits. Morphological changes were observed using Nissl staining and electron microscopy. Cell apoptosis was assessed using Hoechst staining and TUNEL staining. NADPH oxidase (NOX) and caspase-3 activities were determined. The effects of NOX2 and NOX4 knockdown were assessed using small interfering RNA. The expression levels of NOX1, NOX2, and NOX4 were detected using reverse transcription-quantitative PCR and western blotting, and the levels of caspase-3 were detected using western blotting. The diabetic rats exhibited significantly increased plasma glucose, insulin, reactive oxygen species (ROS), S-100B, and MDA levels and decreased SOD levels. Memory function was determined by assessing the percentage of time spent in the target quadrant, the number of times the platform was crossed, escape latency, and mean path length and was found to be significantly reduced in the diabetic rats. Hyperglycemia resulted in notable brain injury, including histological changes and apoptosis in the cortex and hippocampus. The expression levels of NOX2 and NOX4 were significantly upregulated at the protein and mRNA levels, and NOX1 expression was not altered in the diabetic rats. NOX and caspase-3 activities were increased, and caspase-3 expression was upregulated in the brain tissue of diabetic rats. OMT treatment dose-dependently reversed behavioral, biochemical, and molecular changes in the diabetic rats. In vitro, high glucose resulted in increases in reactive oxygen species (ROS), MDA levels, apoptosis, and the expressions of NOX2, NOX4, and caspase-3. siRNA-mediated knockdown of NOX2 and NOX4 decreased NOX2 and NOX4 expression levels, respectively, and reduced ROS levels and apoptosis. The results of the present study suggest that OMT alleviates diabetes-associated cognitive decline, oxidative stress, and apoptosis via NOX2 and NOX4 inhibition.

Protective effect of pregabalin on the brain tissue of diabetic rats.

Diabetes mellitus (DM) is a metabolic disorder characterized by insulin deficiency or insulin resistance. Pregabalin (PGB) is an antiepileptic drug with proven efficacy in the treatment of epilepsy, generalized anxiety disorder, and neuropathic pain. In this study, we aimed to investigate the protective effects of PGB in brain tissue of rats with streptozotocin (STZ)-induced experimental diabetes. Twenty-eight Wistar albino male rats were randomly divided into four groups with seven rats each: (I) Control group, (II) PGB (50mg/kg PBG), (III) DM, and (IV) DM + PGB (50mg/kg/day PGB per orally for 8weeks). Diabetes was induced with an intraperitoneal (i.p.) STZ injection (Sigma Chemical Co Louis Missour, USA) at a dose of 180mg/kg. STZ was dissolved in 0.1M phosphate-citrate tampon (pH 4.5). Paraffin sections were examined using histological and immunohistochemical analyses. To detect oxidative damage biochemically, malondialdehyde (MDA), the end product of lipid peroxidation; superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GPx) which are antioxidant enzymes, levels were studied. In addition, bax, caspase-3 enzyme activities and TUNEL assay were studied to evaluate the apoptosis status. In the DM group, MDA concentrations were significantly higher and GPx and SOD activities were significantly lower compared to the control group. MDA concentrations were significantly lower and SOD activity was significantly higher in the DM + PGB group than in the DM group. The GPx activity in the DM group decreased significantly compared to the control group. In immunohistochemical examinations (Bax, Caspase-3 and TUNEL), the apoptosis rate was significantly lower in the in DM + PGB group than in the DM group. Pregabalin may prevent harmful effects of oxidative damage by decreasing the MDA levels and increasing the SOD levels. In addition, it was thought that PGB may have antiapoptotic properties due to decreased bax and caspase-3 immunoreactivity and TUNEL positivity in PGB groups. Based on these findings, we think that PGB may be effective in reducing the risk of brain damage associated with DM.

Trigonella foenum-graecum seeds extract plays a beneficial role on brain antioxidant and oxidative status in alloxan-induced Wistar rats

AbstractContextTrigonella foenum-graecum (TriFG) exhibits increased scavenger enzymatic activities and reduces the production of reactive oxygen species in diabetic rats.ObjectiveThe present study was aimed to investigate the effect of TriFG on lipid peroxidation levels and antioxidant status in brain tissue of rats exposed to alloxan.Materials and MethodsHealthy male rats (180 ± 10 g) were allocated into five groups. Animals in group 1 maintained on normal tap water served as controls and rats in groups 2, 3, 4, and 5 were treated as experimental groups. Rats in group 2 were intraperitoneally injected with alloxan (120 mg/kg BW) and treated as diabetic rats, whereas rats in groups 3 and 4 were maintained on same experimental regimen as that of rats in groups 1 and 2, respectively, and in addition, they were orally gavaged with herbal extracts of TriFG (0.25 g/kg BW). Diabetic rats treated with glibenclamide in group 5 were used as positive controls.Results and DiscussionSignificant (P < 0.001) increase in the antioxidant enzymes with a significant (P < 0.001) decrease in the lipid peroxidation levels were observed in the brain tissue of diabetic rats treated with TriFG extract as compared to diabetic and glibenclamide-treated rats. No significant changes were observed in pro- and antioxidant levels in brain tissue of rats treated with TriFG extract alone when compared to normal rats. In diabetic rats, brain mitochondrial and cytosolic enzymes like succinate dehydrogenase, glutamate dehydrogenase, and glucose-6-phosphate dehydrogenase activity levels were significantly (P < 0.05) decreased with reversely increased was observed in lactate dehydrogenase activity (P < 0.05).ConclusionsThe findings of the present study suggested that TriFG, through its antioxidant properties, protects brain tissue by mitigating oxidative stress induced by alloxan-exposed rats. TriFG extract significantly increased the antioxidant and oxidative properties in diabetic rats when compared with the control group rats.

Effect of oral supplementation of composite leaf extract of medicinal plants on biomarkers of oxidative stress in induced diabetic Wistar rats

Present study was conducted to evaluate the effect of oral supplementation of composite extract of leaves (CLE) of four medicinal plants; Aegle marmelos, Ocimum sanctum, Murraya koenigii and Azadirachta indica on markers of oxidative stress in brain tissues of alloxan-induced diabetic rats in vivo. Enhanced lipid peroxidation, protein oxidation and reduced antioxidative defence systems were measured in brain tissues of diabetic rats. Supplementation of CLE, once in a day for 35 days significantly (p < .05) protected the peroxidation of lipid, oxidation of protein and ameliorated the antioxidant defence in brain tissue of diabetic rats. It was observed that the insulin-like effect of CLE was dose dependent; higher effect at higher doses. The results of the study suggest that supplementation CLE may provide an overall homeostasis and significant neuro-protection through rescuing brain cells from oxidative abuse and accelerating brain antioxidative defence during advanced stage of hyperglycaemia.

Expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in brain tissue of diabetic rats with ischemia reperfusion.

To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. A total of 60 male Wistar rats were randomly divided into the normal group, sham group, diabetic cerebral infarction group and single cerebral infarction group according to the random number table, with 15 rats in each group. The high sucrose diet and intraperitoneal injection of streptozotocin were performed for the modeling of diabetic rats, while the thread-occlusion method was employed to build the model of cerebral ischemia reperfusion. The immunohistochemical staining was performed to detect the expression of angiostatin, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in the brain tissue. The expression of angiostatin after the reperfusion in the brain tissue of rats in the single cerebral infarction group and diabetic cerebral infarction group was increased 6h after the reperfusion, reached to the peak on 1d and then decreased gradually. The expression of angiostatin in the diabetic cerebral infarction group 6h, 1d, 3d and 7d after the reperfusion was significantly higher than that in the single cerebral infarction group (P<0.05). VEGF began to be increased 1h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak at 6h and then decreased gradually. The expression of VEGF in the diabetic cerebral infarction group at each time point after the reperfusion was significantly lower than that in the single cerebral infarction group (P<0.05). MMP-9 began to be increased 1h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak on 1d and then decreased gradually. The expression of MMP-9 in the diabetic cerebral infarction group at each time point after the reperfusion was significantly higher than that in the single cerebral infarction group (P<0.05). The high glucose environment in which the diabetic cerebral infarction is occurred is to induce the formation of MMP-9 at first and then activate and increase the expression of angiostatin. Afterwards, the expression of VEGF is inhibited, resulting in the poor angiogenesis after cerebral infarction, which thus makes the injury of brain tissue after cerebral infarction even worse than the non-diabetes mellitus.

Protective Effects of Bitter Almond Kernel Oil on Some Biochemical Parameters in Brain Tissue of Diabetic Rats

In this study, we aimed to determine possible protective effects of the bitter almond kernel oil extract on the lipid-soluble vitamins, cholesterol, GSH, total protein, MDA and fatty acid levels of brain tissue in the streptozotocin-induced diabetic Wistar rats. The lipid-soluble vitamins, cholesterol and other sterol levels were measured by HPLC, the fatty acid levels were measured by GC, MDA, GSH and total protein levels were measured by UV-Vis spectrophotometer. Whereas the α-tocopherol and GSH levels were decreased in the diabetes (D) group, these parameters were protected in the diabetes + almond oil (D+AO) group when compared to control (C) group. The total protein and MDA levels were increased in the D group, but their levels were not changed in the D+AO group. The palmitic acid and stearic acid levels were increased in the D and D+AO groups. The arachidonic acid and docosahexaenoic acid levels were increased in the D group, but these fatty acid levels were not changed in the D+AO group when compared to the C group. In conclusion, according to our results, bitter almond oil was shown that some positive effects on the biochemical parameters of brain tissue in the diabetic rats. This oil was protected or prevented the GSH and MDA levels in bitter almond oil extract given group, and these values were closed to control group values.

Modulation of lipid peroxidation, hypolipidemic and antioxidant activities in brain tissues of diabetic rats by fibre – Enriched biscuits

ObjectiveTo investigate the effect of feeding fibre – enriched biscuit on the antioxidant and hypolipidemic activities in brain tissues of diabetic rats. MethodDiabetes was induced by a single intraperitoneal injection of alloxan. Treatment lasted for 14 d, after which the rats were sacrificed by cervical dislocation. Brain tissues were used for the assessment of GSH, catalase, SOD and lipid peroxidation as well as lipid profiles. ResultInduction of diabetes led to a significant decrease in GSH level, elevated SOD and catalase activities. These were significantly modified by the biscuits. There was an elevated level of malondialdehyde in the brain tissues of the untreated diabetic rats; this was significantly reduced by the biscuits. There was a significant decrease in HDL and a significant increase in LDL levels, total cholesterol and triglycerides in the untreated (diabetic) rats. Feeding with fibre – enriched biscuits led to decrease in the levels of total cholesterol, triglyceride, LDL – cholesterol and caused a significant increase in the levels of HDL. ConclusionsThese results suggest a therapeutic and protective effect of the fibre – enriched biscuits against diabetic – induced brain toxicity in rats.

Diyabetin ve Zorlu Yüzme Egzersizinin Sıçan Beyin Dokusunda Yol Açtığı Oksidan Hasar Üzerine Melatoninin Koruyucu Etkisi

Objective: The objective of the present study is to examine how melatonin supplementation affects lipid peroxidation in the brain tissue of diabetic rats subjected to acute swimming exercise. Material and Methods: The study was carried out on 80 Spraque-Dawley type adult male rats, which were equally allocated to 8 groups: Group 1, general control; Group 2, melatonin-supplemented control; Group 3, melatonin-supplemented diabetic control; Group 4, swimming control; Group 5, melatonin-supplemented swimming; Group 6, melatonin-supplemented diabetic swimming; Group 7, diabetic swimming; and Group 8, diabetic control. The animals were injected with 40 mg/kg subcutaneous streptozotocin (STZ). The same dose was repeated after 24 hours. The rats were supplemented with 3 mg/kg/day intraperitoneal (ip) melatonin for 4 weeks. Brain tissue samples were collected from the animals, which were decapitated at the end of the study, to determine malondialdehyde (MDA) (nmol/gram/protein) and glutathione (GSH) (mg/dL/gram protein) levels. Results: The highest MDA values in brain tissue were in Group 7 and 8. Groups 3 and 6 had the highest brain GSH values. Brain GSH values in Group 2 were lower than the values in Groups 3 and 6, but higher than those in all other groups. The lowest GSH values in brain tissue were established in Groups 7 and 8. Conclusion: Results of the present study indicate that the oxidative stress caused by diabetes and acute swimming exercise in rat brain tissue can be offset by melatonin supplementation.

EUK-8 and EUK-134 reduce serum glucose and lipids and ameliorate streptozotocin-induced oxidative damage in the pancreas, liver, kidneys, and brain tissues of diabetic rats

In this study, the effects of EUK-8 and EUK-134, as two newly classified antioxidants, on the sera levels of glucose, insulin, lipids, nitric oxide (NO) and also on the extent of lipid peroxidation (measured in term of thiobarbituric acid reactive substances, TBARS), reactive oxygen species (ROS) formation and the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) as well as reduced glutathione (GSH)] in the liver, pancreas, brain and kidneys of streptozotocin (STZ)-induced diabetic rats were evaluated. Results indicated that oral daily administration of EUK-8, EUK-134 (each at 20 mg/kg), and glibenclamide (2.5 mg/kg), as the control drug, to the diabetic rats for 21 consecutive days improved the sera levels of lipids and glucose along with insulin level to varying extents. In addition, treatment of rats with EUK-8, EUK-134, and/or glibenclamide decreased the TBARS, NO, and ROS levels and increased the activities of SOD and CAT as well as the GSH content in various tissues compared to untreated diabetic rats. In conclusion, this study indicated that EUK-8 and Euk-134 compounds improved the antioxidant status by reducing lipid peroxidation and enhancing the antioxidant enzymes activities in various tissues of diabetic rats.

Expression patterns of ClC-3 mRNA and protein in aortic smooth muscle, kidney and brain in diabetic rats

ClC-3, a member of the ClC family of voltage-gated chloride channels, regulates cell proliferation of cultured rat aortic vascular smooth muscle cells, pathogenesis of allergic rhinitis and tumor cell migration. However, its role in diabetic animals is still unknown. To address this issue, we investigated the expression patterns of ClC-3 in diabetic rats. Five-week-old Sprague-Dawley rats were divided into two groups, 50 non-diabetic control rats (non-DM) and 50 diabetic model rats (DM). ClC-3 mRNA and protein expression in aortic smooth muscle, kidney and brain tissues were examined by fluorimeter-based quantitive RT-PCR assay and Western blot analysis, respectively. ClC-3 mRNA and protein were endogenously expressed in aortic smooth muscle, kidney (cortex and medulla) and brain tissues of both control and streptozotocin-induced diabetic rats. ClC-3 mRNA and protein expression levels were significantly higher in aortic smooth muscle and brain tissues of diabetic rats, but significantly decreased in kidney medulla tissue, relative to non-DM controls. There were no significant differences in ClC-3 mRNA and protein expression in kidney cortex between non-diabetic control and diabetic rats. Furthermore, the altered ClC-3 expression patterns in diabetic rat aortic smooth muscle, brain, and kidney medulla tissues all correlated with the changes in blood glucose levels (p < 0.05). In conclusion, our data show for the first time that diabetes alters both the gene and protein expression of ClC-3 channels. These changes may contribute to the impaired vascular, brain and kidney functions observed in diabetes.

Increase of glial fibrillary acidic protein and S-100B in hippocampus and cortex of diabetic rats: effects of vitamin E

Glial interactions with neurones play vital roles during the ontogeny of the nervous system and in the adult brain. Physical and metabolic insults cause rapid changes in the glial cells and this phenomenon is called reactive gliosis. One of the important events during astrocyte differentiation is the increased expression of glial markers, glial fibrillary acidic protein (GFAP) and S-100B protein. Diabetes mellitus is the most common serious metabolic disorder, which is characterised by functional and structural changes in the peripheral as well as in the central nervous system. In the present study, we aimed to investigate glial reactivity in hippocampus, cortex and cerebellum of streptozotocin-induced diabetic rats by determining the expression of GFAP and S-100B and also to examine the protective effects of vitamin E against gliosis. Western blotting showed increases in total and degraded GFAP content and S-100B protein expression in brain tissues of diabetic rats compared with those of controls. In addition, there was a significant increase in lipid peroxidation in these brain regions of diabetic rats. Both glial markers and lipid peroxidation levels were reversed by vitamin E administration. These findings indicate that streptozotocin-induced diabetes alters degradation and production of GFAP and S-100B, which are markers of reactive astrocytosis. Thus, determination of GFAP and S-100B may provide a relevant marker in the central nervous system for studying neurodegenerative changes in experimental diabetes mellitus. This study also suggests that the gliosis that occurs in diabetes mellitus is mediated, at least indirectly, by free radical formation and antioxidants may prevent reactive gliosis possibly by reducing damaging effects of reactive oxygen species in the central nervous system.