Predictable hematological markers associated with cognitive decline in valid rodent models of cognitive impairment

Endogenous (hyperglycemia) and exogenous (therapeutic, prophylactic, street drugs) factors can considerably contribute to cognitive impairment (CI). Currently, there are few invasive and/or noninvasive markers that correlate with CI and those that do exist require expensive or invasive techniques to predict and accurately measure the cognitive decline. Therefore, we sought to determine hematological markers as predictors of CI in two different chemically induced valid rodent models of CI (streptozotocin induced hyperglycemic model and chemotherapy [doxorubicin/cyclophosphamide] treated rodent model). Hematological markers were analyzed in the above rodent models of CI CI and compared to their respective control groups. There was a significant increase in creatinine kinase, lactate dehydrogenase and aspartate aminotransferase (AST) in the chemotherapy group. Blood urea nitrogen (BUN), alkaline phosphatase (ALP), bilirubin, creatinine and glucose levels were significantly increased in the streptozotocin group. Interestingly, triglycerides were significantly elevated in both the streptozotocin and chemotherapy groups. Previous studies with human subjects have shown a potential link between the increase in triglyceride levels and CI. Likewise, our data indicate a notable correlation with an increase in triglycerides to cognitive impairment in the rodent models. This suggests elevated levels of triglycerides could prove to be a potential noninvasive hematological marker for the increased risk of CI. Further studies are warranted to determine the causal relationship between elevated triglyceride levels and CI.

Synergistic effects of quercetin and regular exercise on the recovery of spatial memory and reduction of parameters of oxidative stress in animal model of Alzheimer's disease

It has widely been reported that the brain in Alzheimer's disease (AD) is affected by increased oxidative stress, and this may have a role in the pathogenesis of this disorder. Quercetin, a polyphenol extensively found in nature, has recently been considered. Also, physical activities have a paradoxical effect on brain function in older adults. Therefore, this study aimed at investigating the synergic effects of quercetin (as chemical treatment) and exercise (as physical treatment) on AD-induced learning and memory impairment. Fifty-six adult male Wistar rats were randomly assigned into one of the following eight groups (n=7): The Control, Sham (saline), AD (intracerebroventricular administration of streptozotocin (STZ)), AD+80 mg/kg Quercetin (STZ+Q80), Quercetin vehicle (1 % Ethanol)+STZ, Exercise pretreatment (EX)+STZ, Off the treadmill+STZ, and EX+Q80+STZ. Quercetin administration was done intraperitoneally for 21 days after STZ injection. The rats ran on the treadmill for one hour a day for 60 days at a speed of 20-22 m/min. After the treatment, the spatial memory and levels of oxidative stress parameters were evaluated. The results showed that STZ caused spatial memory impairment and increased oxidative stress in the hippocampus. Exercise pretreatment or Quercetin injection improved the spatial memory impairment and oxidative stress caused by STZ injection. However, the combination of quercetin and exercise pretreatment was more effective. It can be concluded that the combined exercise pretreatment and Quercetin injection affected the antioxidant defense system and improved STZ-induced memory impairment.

Antidyslipidemic and Antioxidant Activities of Matricaria pubescens (Desf.) Shultz. in Streptozotocin-Induced Diabetic Rats

AIMS

The study aimed to evaluate the antihyperlipidemic and antioxidant activities of Matricaria pubescens.

BACKGROUND

Matricaria pubescens (Desf.) Shultz belongs to Asteraceae family and it is commonly used traditionally for handling diabetes mellitus.

OBJECTIVE

The objective of this study was to assess the antioxidant activity of Matricaria pubescens (Desf.) Shultz and its effect on lipid and lipoprotein profile in normal and streptozotocin-induced diabetic rats.

METHODS

The effect of repeated (7 days of treatment) oral administration of the aqueous extracts of aerial part of Matricaria pubescens (MPAE) at a dose of 40 mg/kg on lipid and lipoprotein profile was examined in normal and streptozotocin-induced diabetic rats. Furthermore, a preliminary phytochemical screening and the quantification of phenolic, flavonoid and tannin contents as well as the antioxidant activity using two methods (FRAP and ABTS) were carried out.

RESULTS

MPAE demonstrated a potent antidyslipidemic effect in diabetic rats by reducing serum levels of triglycerides, total cholesterol and Low-Density Lipoprotein (LDL). In addition, the results showed that the extract is rich in several phytochemical compounds and revealed an important antioxidant activity.

CONCLUSION

In summary, this study proved that Matricaria pubescens (Desf.) Shultz. has a favorable effect on diabetic dyslipidemia.

Orthosiphon stamineus Standardized Extract Reverses Streptozotocin-induced Alzheimer's Disease-Like Condition in a Rat Model

Alzheimer’s disease (AD) is a chronic neurodegenerative brain disease that is characterized by impairment in cognitive functioning as well as the presence of intraneuronal neurofibrillary tangles (NFTs) and extracellular senile plaques. There is a growing interest in the potential of phytochemicals to improve memory, learning, and general cognitive abilities. The Malaysian herb Orthosiphon stamineus is a traditional remedy that possesses anti-inflammatory, anti-oxidant, and free-radical scavenging abilities, all of which are known to protect against AD. Previous studies have reported that intracerebroventricular (ICV) administration of streptozotocin (STZ) mimics a condition similar to that observed in AD. This experiment thus aimed to explore if an ethanolic leaf extract of O. stamineus has the potential to be a novel treatment for AD in a rat model and can reverse the STZ- induced learning and memory dysfunction. The results of this study indicate that O. stamineus has the potential to be potentially effective against AD-like condition, as both behavioral models employed in this study was observed to be able to reverse memory impairment. Treatment with the extract was able to decrease the up-regulated expression levels of amyloid precursor protein (APP), microtubule associated protein tau (MAPT), Nuclear factor kappa-light-chain-enhancer of activated B cells (NFᴋB), glycogen synthase kinase 3 alpha (GSK3α), and glycogen synthase kinase 3 beta (GSK3β) genes indicating the extract’s neuroprotective ability. These research findings suggest that the O. stamineus ethanolic extract demonstrated an improved effect on memory, and hence, could serve as a potential therapeutic target for the treatment of neurodegenerative diseases such as AD.

Selective Modification of Streptozotocin at the C3 Position to Improve Its Bioactivity as Antibiotic and Reduce Its Cytotoxicity towards Insulin-Producing β Cells

With the increasing resistance of bacteria to current antibiotics, novel compounds are urgently needed to treat bacterial infections. Streptozotocin (STZ) is a natural product that has broad-spectrum antibiotic activity, albeit with limited use because of its toxicity to pancreatic β cells. In an attempt to derivatize STZ through structural modification at the C3 position, we performed the synthesis of three novel STZ analogues by making use of our recently developed regioselective oxidation protocol. Keto-STZ (2) shows the highest inhibition of bacterial growth (minimum inhibitory concentration (MIC) and viability assays), but is also the most cytotoxic compound. Pre-sensitizing the bacteria with GlcNAc increased the antimicrobial effect, but did not result in complete killing. Interestingly, allo-STZ (3) revealed moderate concentration-dependent antimicrobial activity and no cytotoxicity towards β cells, and deoxy-STZ (4) showed no activity at all.

Tiliacora triandra extract possesses antidiabetic effects in high fat diet/streptozotocin-induced diabetes in rats

The antidiabetic properties of Tiliacora triandra ethanol extract in diabetic rats induced with high-fat diet (HFD)/streptozotocin (STZ) was investigated. Rats were fed with HFD for 4 weeks to induced insulin resistance, and thereafter administered with 35 mg/kg of STZ to induce diabetes. Diabetic rats received 100 and 400 mg/kg of T. triandra daily for 30 days. The body weight, blood glucose level, food and fluid intake were monitored. Furthermore, biochemical and histological assessment was performed to evaluate the hypoglycemic effect of the extract in the treated rats. T. triandra significantly decreased the blood glucose level, increased the body weight and insulin secretion. Furthermore, T. triandra attenuated hyperlipidemia, improved liver and kidney functions of treated diabetic rats. Thus, T. triandra could effectively attenuate diabetes and it complications. PRACTICAL APPLICATIONS: Tiliacora triandra is a common vegetable consumed in Thailand and Laos. It is traditionally employed in the treatment of fever, cancer, malaria, and diabetes. The extract from the aerial part was investigated for its antidiabetic properties. The results obtained provides important pharmacological information that supports the use of T. triandra in management of diabetes.

Wound healing activity of Pimpinella anisum methanolic extract in streptozotocin-induced diabetic rats

OBJECTIVE

To assess the wound healing potential of Pimpinella anisum on cutaneous wounds in diabetic rats.

METHOD

Full-thickness excisional wounds were made on the back of male, Sprague-Dawley rats with diabetes. The rats were randomly allocated into four treatment groups: 1ml basal cream; tetracycline (3%); Pimpinella anisum 10% for 14 days; and a control group. At days seven, 14 and 21 post-injury, five animals of each group were euthanised, and wounds were assessed through gross, histopathological and oxidant/antioxidant evaluations. Additionally, the dry matter and hydroxyproline contents of the skin samples were measured.

RESULTS

A total of 60 rats were used in the study. A significant decrease in the wound size was observed in treated animals with Pimpinella anisum compared with other groups during the experiment. Additionally, treatment with Pimpinella anisum decreased the number of lymphocytes and improved the number of fibroblasts at the earlier stages and increased a number of fibrocytes at the later stages of wound healing. Other parameters such as re-epithelialisation, tissue alignment, greater maturity of collagen fibres and large capillary-sized blood vessels revealed significant changes when compared with the control. Pimpinella anisum significantly reverted oxidative changes of total antioxidant capacity, malondialdehyde and glutathione peroxidase induced by diabetic wounds (p<0.05). Furthermore, it significantly increased the dry matter and hydroxyproline contents at various stages of wound healing (p<0.05).

CONCLUSION

The present study showed that application of Pimpinella anisum extract promotes wound healing activity in diabetic rats. The wound-healing property of Pimpinella anisum can be attributed to the phytoconstituents present in the plant.

Hesperetin nanoparticles attenuate anxiogenic-like behavior and cerebral oxidative stress through the upregulation of antioxidant enzyme expression in experimental dementia of Alzheimer's type

Background: In this study, we investigate the neuroprotective effects of Hesperetin (Hst) and Nano-Hst on anxiogenic-like behavior and cerebral antioxidant defenses at transcriptional and enzymatic levels in a streptozotocin (STZ)-induced Alzheimer rat model.Methods: Wistar rats were administrated with Hst and Nano-Hst (10 and 20 mg/kg/d) for three weeks. The elevated plus-maze test assessed anxiogenic-like behavior. After behavioral test, activity and gene expression of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GRx) enzymes, as well as malondialdehyde (MDA) and glutathione (GSH) levels, were measured in the cerebral cortex.Results: Based on our results, a rat model of Alzheimer's disease (AD) exhibited anxiogenic-like behavior, activity and gene expression of cerebral antioxidant enzymes and GSH level was decreased while the MDA level was increased. Hst and Nano-Hst treatment reversed anxiogenic-like behavior, and the activities of antioxidant enzymes were elevated. Hst and Nano-Hst effects on the gene expression of CAT, SOD and GRx were confirmed by quantitative real-time PCR (qRT-PCR) in which the expression levels of these genes in the cerebral brain were significantly increased compared to STZ group.Conclusions: These findings indicated that the administration of Hst and Nano-Hst may be used to treat anxiety -related to AD via an up-regulation of cerebral antioxidant enzyme gene.

Xanthotoxin and umbelliferone attenuate cognitive dysfunction in a streptozotocin-induced rat model of sporadic Alzheimer's disease: The role of JAK2/STAT3 and Nrf2/HO-1 signalling pathway modulation

The aim of the present study was to assess the neuroprotective effects of xanthotoxin and umbelliferone in streptozotocin (STZ)-induced cognitive dysfunction in rats. Animals were injected intracerebroventricularly (ICV) with STZ (3 mg/kg) once to induce a sporadic Alzheimer's disease (SAD)-like condition. Xanthotoxin or umbelliferone (15 mg/kg, i.p.) were administered 5 hr after ICV-STZ and daily for 20 consecutive days. Xanthotoxin or umbelliferone prevented cognitive deficits in the Morris water maze and object recognition tests. In parallel, xanthotoxin or umbelliferone reduced hippocampal acetylcholinestrase activity and malondialdehyde level. Moreover, xanthotoxin or umbelliferone increased glutathione content. These coumarins also modulated neuronal cell death by reducing the level of proinflammatory cytokines (tumour necrosis factor-alpha and interleukin-6), inhibiting the overexpression of inflammatory markers (nuclear factor κB [NF-κB] and cyclooxygenase II), and upregulating the expression of NF-κB inhibitor (IκB-α). Interestingly, xanthotoxin diminished phosphorylated JAK2 and phosphorylated STAT3 protein expression, while umbelliferone markedly replenished nuclear factor erythroid-derived 2-like 2 (Nrf2) and haem oxygenase-1 (HO-1) levels. The current study provides evidence for the protective effect of xanthotoxin and umbelliferone in STZ-induced cognitive dysfunction in rats. This effect may be attributed, at least in part, to inhibiting acetylcholinestrase and attenuating oxidative stress, neuroinflammation and neuronal loss.

Protective Effect of Palm Oil-Derived Tocotrienol-Rich Fraction Against Retinal Neurodegenerative Changes in Rats with Streptozotocin-Induced Diabetic Retinopathy

Oxidative stress plays an important role in retinal neurodegeneration and angiogenesis associated with diabetes. In this study, we investigated the effect of the tocotrienol-rich fraction (TRF), a potent antioxidant, against diabetes-induced changes in retinal layer thickness (RLT), retinal cell count (RCC), retinal cell apoptosis, and retinal expression of vascular endothelial growth factor (VEGF) in rats. Additionally, the efficacy of TRF after administration by two different routes was compared. The diabetes was induced in Sprague-Dawley rats by intraperitoneal injection of streptozotocin. Subsequently, diabetic rats received either oral or topical treatment with vehicle or TRF. Additionally, a group of non-diabetic rats was included with either oral or topical treatment with a vehicle. After 12 weeks of the treatment period, rats were euthanized, and retinas were collected for measurement of RLT, RCC, retinal cell apoptosis, and VEGF expression. RLT and RCC in the ganglion cell layer were reduced in all diabetic groups compared to control groups (p < 0.01). However, at the end of the experimental period, oral TRF-treated rats showed a significantly greater RLT compared to topical TRF-treated rats. A similar observation was made for retinal cell apoptosis and VEGF expression. In conclusion, oral TRF supplementation protects against retinal degenerative changes and an increase in VEGF expression in rats with streptozotocin-induced diabetic retinopathy. Similar effects were not observed after topical administration of TRF.

Ameliorating effect of pomegranate peel extract supplement against type 1 diabetes-induced hepatic changes in the rat: biochemical, morphological and ultrastructural microscopic studies

BACKGROUND

Diabetes mellitus could result from disorders in insulin secretion or receptors mainly characterised by hyperglycaemia. Natural antioxidants including pomegranate are traditionally used as hypoglycaemic agents. The present research was designed to evaluate the possible therapeutic role of pomegranate peel extract (PPE) against type 1 diabetic-induced hepatic biochemical and histological alteration.

MATERIALS AND METHODS

Adult male Wistar rats (n = 48) were sorted into four groups: G1: control group, G2: normal rats received PPE, G3: streptozotocin (STZ)-diabetic rats, received IP STZ (55 mg/kg body weight), and G4: diabetic rats post-treated with PPE (200 mg/kg body weight/day). Effectiveness of PPE was assessed by measuring serum glucose, liver enzymes, and morphological features of liver tissue using light and electron microscopy.

RESULTS

Histological examination showed degenerative necrotic changes in diabetic rat liver which were improved by post-treatment with PPE. Biochemical results confirmed microscopic morphological and ultrastructural findings.

CONCLUSIONS

Pomegranate peel extract was found to have a moderate therapeutic effect against hepatic alterations in male rats. It could be advised for diabetic patients suffering from early alterations of liver functions.

The beneficial effects of Agaricus blazei Murrill on hepatic antioxidant enzymes and the pancreatic tissue recovery in streptozotocin-induced diabetic rats

Agaricus blazei Murrill (ABM), is a medicinal mushroom, has beneficial effects on diabetes mellitus. In this study, ABM extracts (ethanol extract, EE and ethyl acetate extract, EA) were evaluated to explore the beneficial effect on hepatic antioxidant activity and recovery of the pancreatic tissue in streptozotocin-induced diabetic rats. The hepatic antioxidant activities of ABM extracts were analyzed by superoxide dismutase, catalase activity, glutathione, aspartate transaminase, and alanine transaminase. Moreover, the effects of ABM extracts on pancreatic tissue restoration were investigated by histopathological analysis. The results revealed that the EA showed a better protective effect on hepatic antioxidant activity and recovery of the impaired pancreatic tissues, compared to EE. The results suggested that ABM treatment could effectively reduce oxidative stress and contribute to pancreatic tissue recovery. Therefore, ABM could be used as a functional food to control diabetes. PRACTICAL APPLICATIONS: The research may contribute to the development of ABM as functional foods or dietary supplements for diabetes in the future.

Effects of thiamine treatment on oxidative stress in experimental diabetes

AIM

Hyperglycemia, oxidative stress and hyperlipidemia are features of diabetes mellitus. Thiamine has beneficial effects on carbohydrate metabolism and it was proposed that this vitamin has antihyperlipidemic and antioxidant effects. Our aim was to investigate the effects of thiamine on oxidative stress and metabolic changes in streptozotocin (STZ) induced diabetic rats.

METHOD

Diabetes was induced by a single intraperitoneal injection of STZ. Thiamine (6 mg/kg) was added to drinking water for five weeks. The rats were divided into four groups: control rats; thiamine treated control rats; diabetic rats; thiamine treated diabetic rats. Plasma and tissue malondialdehyde (MDA) levels were measured by high-performance liquid chromatography and spectrophotometry, respectively. Paraoxonase (PON) and arylesterase (AE) activities were measured with spectrophotometric methods, and erythrocyte superoxide dismutase (SOD) and blood glutathione peroxidase (GSH-Px) activities were determined using commercial kits.

RESULTS

Thiamine treatment reduced plasma and tissue MDA levels, serum glucose, total cholesterol and triglyceride levels, and increased serum high density lipoprotein- cholesterol and insulin levels, serum PON and AE, erythrocyte SOD and blood GSH-Px activities.

CONCLUSION

Thiamine significantly improves oxidative stress and has hyperinsulinemic and antihyperlipidemic effects so we suggest that thiamine might be used as a supportive therapeutic agent in diabetes (Tab. 2, Fig. 3, Ref. 53).

The novel GLP-1/GIP analogue DA5-CH reduces tau phosphorylation and normalizes theta rhythm in the icv. STZ rat model of AD

INTRODUCTION

Alzheimer's disease (AD) is the most common progressive neurodegenerative disease for which there is no cure. Recent studies have shown a close link between type 2 diabetes and AD, which suggested that drugs for type 2 diabetes may be effective for AD. GLP-1 and GIP are incretin hormones that can ameliorate diabetes.

METHODS

In the present study, we tested the novel dual GLP-1/GIP receptor agonist DA5-CH in the icv. streptozotocin (STZ)-induced insulin desensitization model of AD in rats to explore the protective effects of DA5-CH.

RESULTS

The results show that DA5-CH could reverse the STZ-induced working memory impairments in a Y-maze tests, and spatial memory impairments in the water maze task, and decrease the levels of phosphorylated tauS396 protein in the hippocampus. In EEG recordings, STZ treatment diminished the power of the theta band frequency. DA5-CH was able to increase the energy of theta band activity in the hippocampal CA1 region. The drug also increased the expression of synapse-related proteins in the hippocampus. After DA5-CH treatment, mitochondrial stress was alleviated as shown by the improved ratio of Bax/Bcl-2 in the hippocampus. Growth factor signaling was also normalized as shown by the increased level of the transcription factor P-CREBS133 . In addition, we were able to show that DA5-CH can cross the blood-brain barrier at an increased rate compared with other dual GLP-1/GIP or single GLP-1 receptor agonists.

CONCLUSION

Therefore, our results demonstrate that DA5-CH has neuroprotective effects in the STZ-induced animal model and that DA5-CH has potential to treat neurodegenerative disorders such as AD.

Quantitative magnetic susceptibility assessed by 7T magnetic resonance imaging in Alzheimer's disease caused by streptozotocin administration

Streptozotocin treatment has emerged as an alternative model of sporadic Alzheimer's disease (SAD). Streptozotocin-induced alterations in iron and calcium levels reflect magnetic susceptibility changes, while susceptibility distribution in the cerebral regions has not been reported yet. This study aimed to investigate susceptibility distribution in the limbic system after streptozotocin administration to cynomolgus monkeys for exploring informative SAD biomarkers. Quantitative susceptibility mapping (QSM) using 7T magnetic resonance imaging (MRI) was utilized to quantitatively compare the susceptibility distributions in monkeys with sporadic Alzheimer disease and age-matched healthy controls. Compared to healthy controls, overall susceptibility values differed in the SAD models. Notable substantial susceptibility changes were observed in the hypothalamus with a 4.38-time decrease (AD: -47.45±12.19 ppb, healthy controls: 14.02±9.51 ppb) and in the posterior parts of the corpus callosum with a 2.83-times increase (AD: 31.49±15.90 ppb; healthy controls: 11.13±4.02 ppb). These susceptibility alterations may reflect neuronal death, and could serve as key biomarkers in the SAD. These results may be useful for specifying AD pathologies such as cognitive and non-cognitive symptoms.

Antidiabetic Activity of Extracts of Terminalia brownii Fresen. Stem Bark in Mice

Background

Diabetes mellitus is a chronic metabolic disorder that imposes a huge health and economic burden on societies. Because the currently available medications have many drawbacks, it is important to search for alternative therapies. Medicinal plants used in traditional medicines are ideal candidates. Hence, this study was undertaken to investigate the antidiabetic activity of crude extract and solvent fractions from the stem bark of Terminalia brownii Fresen. (Combretaceae) in mice.

Materials and Methods

The in vitro α-amylase inhibition assay was performed using the chromogenic 3, 5-dinitrosalicylic acid (DNSA) method while the antihyperglycemic activity was assessed using three mouse models: streptozotocin-induced diabetic mice, normoglycemic mice, and oral glucose challenged mice. Experimental diabetes was induced by a single intraperitoneal injection of streptozotocin at a dose of 150 mg/kg and animals with fasting blood glucose level (BGL) >200 mg/dL were considered diabetic. Glibenclamide (5 mg/kg) was used as a standard drug. Fasting BGL and body weight were used to assess the antidiabetic activity. The result was analyzed using GraphPad Prism software version 8 and one-way ANOVA followed by Tukey’s post hoc test with p<0.05 considered as statistically significant.

Results

The crude extract of T. brownii at all tested dose levels (250, 500 and 750 mg/kg) showed a significant BGL reduction in all the three animal models. Moreover, the ethyl acetate and aqueous fractions (at 500 mg/kg) significantly (p<0.01) reduced the BGL in the streptozotocin induced diabetic model. The crude extract and different solvent fractions also showed a dose-dependent in vitro α-amylase inhibitory activity and improvement of body weight.

Conclusion

T. brownii crude extract and its solvent fractions showed a significant antihyperglycemic activity in STZ induced diabetic mice, hypoglycemic activity and improvement of oral glucose tolerance in normal mice.

Cichorium intybus attenuates streptozotocin induced diabetic cardiomyopathy via inhibition of oxidative stress and inflammatory response in rats

The aim of the present study was to investigate the effects of Cichorium intybus on lipid peroxidation activities of both enzymatic and non-enzymatic antioxidants, inflammatory mediators, myocardial enzymes and histopathology of cardiac tissues in experimental diabetic cardiomyopathy (DCM). DCM was induced by single intraperitoneal injection of streptozotocin (STZ) (40 mg/kg) combined with high energy intake in rats. Seed extract of Cichorium intybus (CIE) (250 mg/kg & 500 mg/kg) was administered orally once a day for 3 weeks. Phytochemical investigations of seed extract revealed presence of some active ingredients such as alkaloids, tannins, saponin, phenols, glycosides, steroids, terpenoids and flavonoids. Seed extract of Cichorium intybus confirmed a significant potency towards restoring the blood glucose, an elevation of the levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS), blood glutathione (GSH), TNF-α and IL-6 and a reduction in the levels of catalase (CAT) was observed following the STZ treatment. Oxidative stress was accompanied by myocardial degeneration as evidenced by histopathological examination of cardiac tissues. Administration of CIE reduced the lipid peroxides level in heart. Serum levels of AST, GSH, LDH and SOD were brought down to physiological levels by CIE in STZ induced DCM rats. CIE also markedly down-regulated serum TNF-α and IL-6 levels. Catalase that was reduced in serum was brought back to near normal level. The extensive necrotic changes of cardiac tissue by STZ was minimized to normal morphology upon CIE administration. The study demonstrates the cardioprotective effect of CIE via inhibition of oxidative stress and pro-inflammatory cytokines.

Free fatty acid receptor 3 differentially contributes to β-cell compensation under high-fat diet and streptozotocin stress

The free fatty acid receptor 3 (FFA3) is a nutrient sensor of gut microbiota-generated nutrients, the short-chain fatty acids. Previously, we have shown that FFA3 is expressed in β-cells and inhibits islet insulin secretion ex vivo. Here, we determined the physiological relevance of the above observation by challenging wild-type (WT) and FFA3 knockout (KO) male mice with 1) hyperglycemia and monitoring insulin response via highly sensitive hyperglycemic clamps, 2) dietary high fat (HF), and 3) chemical-induced diabetes. As expected, FFA3 KO mice exhibited significantly higher insulin secretion and glucose infusion rate in hyperglycemic clamps. Predictably, under metabolic stress induced by HF-diet feeding, FFA3 KO mice exhibited less glucose intolerance compared with the WT mice. Moreover, similar islet architecture and β-cell area in HF diet-fed FFA3 KO and WT mice was observed. Upon challenge with streptozotocin (STZ), FFA3 KO mice initially exhibited a tendency for an accelerated incidence of diabetes compared with the WT mice. However, this difference was not maintained. Similar glycemia and β-cell mass loss was observed in both genotypes 10 days post-STZ challenge. Higher resistance to STZ-induced diabetes in WT mice could be due to higher basal islet autophagy. However, this difference was not protective because in response to STZ, similar autophagy induction was observed in both WT and FFA3 KO islets. These data demonstrate that FFA3 plays a role in modulating insulin secretion and β-cell response to stressors. The β-cell FFA3 and autophagy link warrant further research.

Phosphoinositide 3-kinase inhibitor AS605240 ameliorates streptozotocin-induced Alzheimer's disease like sporadic dementia in experimental rats

The quest for chemical entities able to curb the action of the phosphoinositide 3-kinase, (PI3K)/protein kinase B (AKT) signaling pathways is evolving as a potential therapeutic strategy for the treatment and/or prevention of neurodegenerative disorders including Alzheimer's disease (AD). In this study, the effects of a PI3K inhibitor, AS605240 on cognitive dysfunction and antioxidative defense parameters against intra-cerebroventricular-streptozotocin (ICV-STZ)-induced rat model of sporadic AD was evaluated. ICV administration of a single dose of STZ (3 mg/kg) was performed to induce behavioral and biochemical changes in rats using the stereotaxic technique. Animals were administered with varying doses of AS605240 (5, 10 and 15 mg/kg) orally, 1 h before ICV-STZ on day 1 and continued once daily for four weeks. The behavioral parameters (passive avoidance and Morris water maze), antioxidative defense parameters, amyloid-beta (Aβ) protein expression by Western blotting and immunostaining technique were estimated in brain tissue. AS605240 dose-dependently and significantly (p < 0.05 and p < 0.01 and p < 0.001) improved ICV-STZ-induced cognitive impairment and attenuated the altered antioxidative related parameters including superoxide dismutase, lipid peroxidation, glutathione and nitrite levels. Further, the increased Aβ protein expression levels in brain tissue were markedly restored with AS605240 treatment. In conclusion, our study demonstrated that AS605240 exhibited immense potential in attenuating STZ-induced sporadic AD features in rats and may be developed as a therapeutic agent in the treatment and management of sporadic AD.

Effect of Ficus glomerata leaf extract in streptozotocin-induced early diabetic complications and its characterization by LC-MS

Diabetes mellitus is a complex metabolic disorder that leads to various micro-vascular complications. The present study elucidated the effect of chloroform extract of leaves of Ficus glomerata (CHFG) in streptozotocin-induced early diabetic renal and neural complications. Wistar rats were injected with STZ (55 mg/kg, i.p.) to produce experimental diabetes. Two weeks after the stabilization of diabetes, CHFG extract at the dose of 200 and 400 mg/kg (CHFG 200 and CHFG 400) and metformin at the dose of 250 mg/kg (Met 250) was administered to the diabetic rats for further two weeks. Diabetic rats showed an increase in blood glucose, plasma urea, uric acid, creatinine, triglyceride, and total cholesterol level. The change in behavioral parameters such as thermal hyperalgesia and cold allodynia with compromised sciatic nerve and kidney antioxidant status were seen in diabetic rats. Diabetic rats treated with CHFG 200, CHFG 400, and Met 250 showed a decrease in blood glucose, plasma urea, uric acid, creatinine, triglyceride, and total cholesterol level. Also, it improved altered behavioral parameters such as thermal hyperalgesia and cold allodynia. It also restored the sciatic nerve and kidney antioxidant status. The results of kidney and sciatic nerves histopathological study were in line with the results of biochemical parameters that confirmed the favorable role of CHFG. Characterization of CHFG by LC-MS revealed the presence of diverse phytoconstituents, which might be responsible for its protective effect.

A light microscopic investigation of the renoprotective effects of α-lipoic acid and α-tocopherol in an experimental diabetic rat model

We investigated the effects of α-lipoic acid (AL) and α-tocopherol (AT) on renal histopathology in a streptozotocin (STZ) induced diabetic rat model. Adult male rats were divided into six groups: group 1, saline only; group 2, AL only; group 3, AT only; group 4, STZ only; group 5, STZ + AL; group 6 STZ + AT. Experimental diabetes was induced by STZ. AL and AT were administered for 15 days. Kidney sections were examined using a light microscope after hematoxylin and eosin (H & E), periodic acid-Schiff (PAS) and caspase-3 staining. Histological damage to glomeruli, tubule epithelial cells and basement membrane was observed in group 4. Administration of AT and AL reduced renal injury in the diabetic rats. Group 5 exhibited a greater curative effect on diabetic rats than group 6. AT and AL may be useful for preventing diabetic renal damage.

Association of increased renal Cyp24a1 gene expression with low plasma 1,25-dihydroxyvitamin D levels in rats with streptozotocin-induced diabetes

Decreases in plasma vitamin D concentrations have been reported in diabetes, although the mechanism involved in this decrease is unclear. Here, we investigated the association between Cyp24a1, a vitamin D catabolic enzyme, and abnormalities in vitamin D metabolism in streptozotocin-induced diabetes rats, an animal model of type 1 diabetes. Plasma 1,25-dihydroxyvitamin D [1,25(OH)₂D] levels were significantly lower in streptozotocin-induced diabetes rats and renal Cyp24a1 mRNA expression levels were increased. Western blotting analysis of streptozotocin-induced diabetes rats kidney tissues with anti-CYP24A1 antibody showed a strong signal around 40 kDa, which differs from the predicted 50–55 kDa molecular weight for full-length Cyp24a1 and could represent the Cyp24a1-splicing variant that lacks exons 1 and 2. We observed high levels of renal Cyp24a1-splicing variant mRNA expression in streptozotocin-induced diabetes rats. We also confirmed transcriptional up-regulation of endogenous Cyp24a1 mRNA expression through glucocorticoid receptors by glucocorticoid in opossum kidney proximal cells. Taken together, our results indicated that high Cyp24a1 expression levels may play a role in the decrease of plasma 1,25(OH)₂D levels in streptozotocin-induced diabetes rats. High plasma corticosterone levels in diabetes may affect transcriptional regulation to promote increases in Cyp24a1 expression.

Design and optimization of crocetin loaded PLGA nanoparticles against diabetic nephropathy via suppression of inflammatory biomarkers: a formulation approach to preclinical study

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus whose expand process is linked with the fibrosis, renal hypertrophy and inflammation. The current study was to formulate and optimize the nano-formulation of crocetin (CT-PLGA-NPs) against Streptozotocin-induced renal nephropathy in rats. Double emulsion evaporation technique was used for the preparation of CT-PLGA-NPs. CT-PLGA-NPs were scrutinized for polydispersity index, size, gastric stability, entrapment, drug-loading capacity and in-vitro drug release and in vivo preclinical study. Single intraperitoneal injection of streptozotocin (STZ) (55 mg/kg) and rats were divided into different group. Renal function and metabolic parameters of urine and serum were estimated. Fibrotic protein, renal pro-inflammatory cytokines and degree of renal damage expression were also determined. We also estimated the fibronectin, type IV collagen and transforming growth factor-β1 for a possible mechanism of action. Crocetin supplement (10 mg/kg) and CT-PLGA-NPs exhibited the accumulation of the drug in kidney and liver of diabetic rats. Crocetin reduced the BGL and enhanced plasma insulin and body weight. Dose dependent treatment of crocetin significantly (p < .001) down-regulated the expression of renal tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin (IL)-1β (IL-1β) and Monocyte Chemoattractant Protein-1 (MCP-1). Crocetin significantly (p < .001) altered the expression of fibronectin, type IV collagen, and transforming growth factor-β1 (TGF-1β). Crocetin significantly (p < .001) down-regulated the protein kinase C activity and the expression of nuclear factor κB (NF-κB) p65 activity and protein production in renal tissue. On the basis of the available result, we can conclude that nano-formulation of crocetin could attenuate the diabetic nephropathy via antifibrotic and anti-inflammatory effect.

Alteration in memory cognition due to activation of caveolin-1 and oxidative damage in a model of dementia of Alzheimer's type

OBJECTIVE

The present study aims to investigate the role of caveolin-1 in dementia of Alzheimer's type using intracerebroventricular streptozotocin (ICV-STZ)-induced neurodegeneration model in rats.

MATERIALS AND METHODS

Male Wistar rats (220-260 g) were employed. STZ 3 mg/kg via ICV route was given once to cause neuronal injury. Daidzein - a caveolin inhibitor at 0.2, 0.4, and 0.6 mg/kg s.c. were given daily whereas minoxidil - a caveolin activator was given at 0.45 mg/kg, i.p. on alternate days for 28 days. STZ was also given at its submaximal dose 1.5 mg/kg to minoxidil group only.

RESULTS

ICV-STZ control animals exhibited cognitive and neurological deficits on the Morris water maze, elevated plus maze, and balance beam tests (P < 0.0001). Treatment with daidzein significantly restored memory impairments and decreased oxidative damage whereas minoxidil potentiates the effect of STZ causing significant impairment in memory. Significant oxidative stress such as lipid peroxidation and glutathione (P < 0.0001) were also observed due to ICV-STZ administration resulting in neuronal damage which was significantly prevented by treatment with daidzein in brain tissues.

CONCLUSION

The findings from the present investigation may conclude that the caveolin-1 from caveolae at the cell membrane induces memory deficits and oxidative stress phenotype that resemble the neurological phenotype of Alzheimer's disease. Further studies are warranted to gauge the effect of caveolin dyshomeostasis on the amyloidogenic cascade.

Dendropanax morbifera Protects against Renal Fibrosis in Streptozotocin-Induced Diabetic Rats

The aquatic extract of Dendropanax morbifera (DP) is typically consumed as a beverage in Korea and China and is also used in various traditional medicines. However, the functional role of DP on diabetes-induced renal fibrosis is unclear. Here, the protective effects of DP extract against diabetes-induced renal fibrosis were evaluated. Streptozotocin (STZ, 60 mg/kg) was injected intraperitoneally in rats to induce diabetes. After 5 days, DP extract (25 mg/kg/day) and metformin (50 mg/kg/day) were administered orally to diabetic rats for 28 days. DP administration protected both body and organ weight loss in STZ-treated diabetic rats. Significant improvements in serum blood urea nitrogen (BUN), creatinine, and oxidative stress parameters were observed in diabetic rats by DP administration. DP extract markedly protected diabetic-induced histopathological damages in the kidney and pancreas. A significant reduction was observed in microalbumin, kidney injury molecule-1 (KIM-1), selenium binding protein-1 (SBP1), and pyruvate kinase muscle isozyme M2 (PKM2) levels in the urinary excretion of diabetic rats after the administration of DP extract. The expression of pro-inflammatory cytokines and fibrosis marker levels were significantly reduced in the kidney of diabetic rats. Our results strongly indicate that DP extract exhibits protective activity against diabetes-induced renal fibrosis through ameliorating oxidative stress and inflammation. Therefore, we suggest that DP extract can be used as a preventive agent on the progression of diabetic nephropathy and renal fibrosis.