Effect of crocin and losartan on biochemical parameters and genes expression of FRMD3 and BMP7 in diabetic rats.

BACKGROUND: Diabetes is a multifactorial and growing disease, one of the severe complications of which is diabetic nephropathy (DN), which is the most common cause of chronic renal failure. FERM domain containing 3 (FRMD3) is responsible for maintaining the shape and integrity of nephron cells, and bone morphogenetic protein 7 (BMP7) helps maintain function and reduce kidney damage. This study aimed to evaluate the effect of crocin and losartan on biochemical parameters and the expression of FRMD3 and BMP7 genes in streptozotocin (STZ)-induced diabetic rats. METHODS: Forty male Wistar rats were randomly divided into five experimental groups as healthy, diabetic control (D), crocin, losartan, and diabetic rats treated with losartan-crocin (n = 8). A single dose of STZ (50 mg/kg intraperitoneally injection) was used to induce diabetes. Four weeks after induction of diabetes, rats received crocin (50 mg/kg) and losartan (25 mg/kg) daily for four weeks orally. Rats were sacrificed at the end of the intervention, and blood samples were taken to determine serum levels of glucose, urea, creatinine (Cr), malondialdehyde (MDA), and thiol. Real-time polymerase chain reaction (PCR) was used to assess the expression of the FRMD3 and BMP7 genes in the kidney samples. RESULTS: Diabetes induction increased serum levels of glucose, Cr, urea, MDA, and thiol, but decreased BMP7 and FRMD3 genes expression. Treatment with crocin and losartan decreased these biochemical parameters and increased the expression of the BMP7 and FRMD3 genes. DISCUSSION: Crocin may be a promising therapeutic agent for preventing and improving diabetes-related kidney disease due to its antidiabetic and antioxidant properties.

Wound healing activity of Salvia huberi ethanolic extract in streptozocin-induced diabetic rats.

Objective: The aim of this study was to examine the in vivo wound healing potential of Salvia huberi Hedge (endemic to Turkey) on excision and incision wound models in diabetic rats. Method: Male Wistar albino rats, 3-4 months old and weighing 180-240g were used. The animals were randomly divided into five groups including Control, Vehicle and Fito reference, and two different concentrations (0.5% and 1% weight/weight (w/w)) of ethanol extract of Salvia huberi were investigated in both wound models on streptozocin-induced diabetic rats using macroscopic, biomechanical, biochemical, histopathological, genotoxic and gene expression methods over both seven and 14 days. Fito cream (Tripharma Drug Industry and Trade Inc., Turkey) was used as the reference drug. Results: A total of 60 rats were used in this study. Salvia huberi ointments at 0.5% and 1% (w/w) concentrations and Fito cream showed 99.3%, 99.4% and 99.1% contraction for excision wounds, and 99.9%, 97.0% and 99% contraction for incision wounds, respectively. In Salvia huberi ointments and Fito cream groups, re-epithelialisation increased dramatically by both day 7 and day 14 (p<0.05). By day 14, low hydroxyproline and malondialdehyde (MDA) levels, and high glutathione (GSH) levels were observed in the Salvia huberi ointment groups. After two application periods, damaged cell percent and genetic damage index values and micronucleus frequency of Salvia huberi ointment treatment groups were lower than Control and Vehicle groups (p<0.001). A growth factor expression reached a high level by day 7 in the Control group; in Salvia huberi-treated groups it was decreased. Conclusion: The study showed that application of Salvia huberi ointments ameliorated the healing process in diabetic rats with excisional and incisional wounds and may serve as a potent healing agent.

Wound healing activity of Salvia huberi ethanolic extract in streptozocin-induced diabetic rats.

Objective: The aim of this study was to examine the in vivo wound healing potential of Salvia huberi Hedge (endemic to Turkey) on excision and incision wound models in diabetic rats. Method: Male Wistar albino rats, 3-4 months old and weighing 180-240g were used. The animals were randomly divided into five groups including Control, Vehicle and Fito reference, and two different concentrations (0.5% and 1% weight/weight (w/w)) of ethanol extract of Salvia huberi were investigated in both wound models on streptozocin-induced diabetic rats using macroscopic, biomechanical, biochemical, histopathological, genotoxic and gene expression methods over both seven and 14 days. Fito cream (Tripharma Drug Industry and Trade Inc., Turkey) was used as the reference drug. Results: A total of 60 rats were used in this study. Salvia huberi ointments at 0.5% and 1% (w/w) concentrations and Fito cream showed 99.3%, 99.4% and 99.1% contraction for excision wounds, and 99.9%, 97.0% and 99% contraction for incision wounds, respectively. In Salvia huberi ointments and Fito cream groups, re-epithelialisation increased dramatically by both day 7 and day 14 (p<0.05). By day 14, low hydroxyproline and malondialdehyde (MDA) levels, and high glutathione (GSH) levels were observed in the Salvia huberi ointment groups. After two application periods, damaged cell percent and genetic damage index values and micronucleus frequency of Salvia huberi ointment treatment groups were lower than Control and Vehicle groups (p<0.001). A growth factor expression reached a high level by day 7 in the Control group; in Salvia huberi-treated groups it was decreased. Conclusion: The study showed that application of Salvia huberi ointments ameliorated the healing process in diabetic rats with excisional and incisional wounds and may serve as a potent healing agent.

Antihyperglycemic Effect of Rhamnus alaternus L. Aqueous Extract in Streptozotocin-induced Diabetic Rats.

BACKGROUND: Traditionally, the aerial parts of Rhamnus alaternus L. have been widely used in Mediterranean countries, including Morocco, to cure diabetes. AIM: This study aimed to evaluate the antidiabetic effect of Rhamnus alaternus aqueous extract in streptozotocin(STZ)-induced diabetic rats. OBJECTIVE: This work aimed to evaluate the antihyperglycemic effect of Rhamnus alaternus aqueous extract (RAAE) in normal and diabetic rats. Then the phytochemical composition, antioxidant capacity, and potential toxicity of RAAE were also assessed. METHODS: The effects of acute (6 h) and subchronic (7 days) oral administration of RAAE (20 mg/kg) on blood glucose levels and lipid profiles were evaluated in normal and diabetic rats. Besides, a preliminary phytochemical screening, quantification of phenolic, flavonoid, and tannin contents as well as the antioxidant activity, using the DPPH method, were evaluated. Additionally, the toxicity of the aqueous extract (5 mg/kg) was also studied and the LD50 value was determined. RESULTS: RAAE (20 mg/kg) over 7 days of oral administration significantly decreased the blood glucose levels both in normal and diabetic rats. In diabetic rats, this extract also improved oral glucose tolerance. In addition, RAAE possessed significant antioxidant activity. According to preliminary phytochemical research, RAAE contains several chemical compounds, including alkaloids, polyphenols, flavonoids, cyanidins, anthraquinones, and sterols. On the other hand, the quantitative phytochemical study of the aqueous extract revealed a considerable amount of total phenolic compounds (497.93 ± 3.38 mg GAE/1g of RAAE), flavonoids (100.42 ± 0.32 mg RE/ g of RAAE), and tannins (14.32 ± 0.37 mg CE/1g of RAAE). CONCLUSION: We conclude that RAAE exerts a significant antihyperglycemic effect in STZ-induced diabetic rats at a low dose. Indeed, more research is still required to support the use of this plant in the Moroccan population's diabetes care.

TXNIP overexpression in mice enhances streptozotocin-induced diabetes severity.

Thioredoxin-interacting protein (TXNIP) is a key player in the endocrine pancreas; it induces beta cell apoptosis, such that TXNIP deficiency promotes beta cell survival. To study its function in more detail, we generated transgenic mice with ubiquitous overexpression of TXNIP. CBATXNIP/+ mice were investigated under basal conditions and after being challenged in diet-induced obesity (DIO) and streptozotocin-induced type 1 diabetes mellitus (T1DM) models. TXNIP overexpression caused no effect in the DIO model, contrasting to the already reported TXNIP-deficient mice. However, in the T1DM background, CBATXNIP/+ animals showed significantly enhanced blood glucose and increased glucose levels in a glucose tolerance test. Finally, the beta cell mass of CBATXNIP/+ transgenic animals in the T1DM model was significantly reduced compared to control littermates. Our study demonstrates that overexpression of TXNIP doesn't affect blood glucose parameters under basal conditions. However, overexpression of TXNIP in a T1DM model enhances the severity of the disease.

Diazoxide improves muscle function in association with improved dyslipidemia and decreased muscle oxidative stress in streptozotocin-induced diabetic rats.

AIM/INTRODUCTION: Diabetes Mellitus is a chronic degenerative disease, and its main biochemical characteristic is hyperglycemia due to impaired insulin secretion, resistance to peripheral actions of insulin, or both. Hyperglycemia causes dyslipidemia and stimulates oxidative damage, leading to the main symptoms, such as fatigue and culminates in diabetic complications. Previous studies have shown that ATP-sensitive potassium channels counteract muscle fatigue and metabolic stress in healthy mouse models. To determine the effect of diazoxide on muscle strength development during diabetes, we tested the effect of diazoxide in streptozotocin-diabetic rats in muscle function, lipid profile and oxidative stress biomarkers. MATERIALS AND METHODS: Wistar rats were divided into 4 groups of six animals each: (1) Control group, (2) diabetes group, (3) Control group + diazoxide, and (4) Diabetic + diazoxide (DB + DZX). 4 weeks after rats were sacrificed, soleus and extensor digitorum longus muscles (EDL) were extracted to prepare homogenates and serum was obtained for biochemical measurements. Oxidative damage was evaluated by the thiobarbituric acid method and the fluorescent for reactive oxygen species (ROS) probe 2,4-H2DCFDA, respectively. RESULTS: Diabetic rats with diazoxide administration showed an increase in the development of muscle strength in both muscles; in turn, the onset of fatigue was longer compared to the group of diabetic rats without treatment. Regarding the lipid profile, diazoxide decreased total cholesterol levels in the group of diabetic rats treated with diazoxide (x̅46.2 mg/dL) compared to the untreated diabetic group (x̅=104.4 mg/dL); secondly, diazoxide decreased triglyceride concentrations (x̅=105.3 mg/dL) compared to the untreated diabetic rats (x̅=412.2 mg/dL) as well as the levels of very low-density lipoproteins (x̅=20.4 mg/dL vs. x̅=82.44 mg/dL). Regarding the various markers of oxidative stress, the diabetic group treated with diazoxide was able to reduce the concentrations of TBARS and total reactive oxygen species as well as preserve the concentrations of reduced glutathione. CONCLUSION: Diazoxide administration in diabetic rats increases muscle strength development in EDL and soleus muscle, decreases fatigue, reduces cholesterol and triglyceride concentrations and improves oxidative stress parameters such as TBARS, ROS, and glutathione status.

Co-administration of metformin and/or glibenclamide with losartan reverse NG-nitro-l-arginine-methyl ester-streptozotocin-induced hypertensive diabetes and haemodynamic sequelae in rats.

Over the years, there have been opinions on whether to reduced blood pressure (BP) to a different levels in patients with diabetes mellitus. Hence, this study investigated the efficacy of the co-administration of losartan (angiotensin receptor blocking antihypertensive agent) with metformin and/or glibenclamide (antidiabetic agents) on hypertensive-diabetic experimental rats induced by NG-nitro-l-arginine-methyl-ester hydrochloride (l-NAME), and streptozotocin (STZ). STZ (45 mg/kg, i.p.)-induced diabetic rats combined with l-NAME (40 mg/kg, p.o.)-induced hypertension were allotted into different groups. Group 1 received distilled water (10 mL/kg) and served as normal control, group 2 comprised hypertensive diabetic rats with distilled water, groups 3-5 were hypertensive-diabetic rats but received combination treatments of losartan + metformin, losartan + glibenclamide, and losartan + metformin + glibenclamide daily for 8 weeks, respectively. Our finding revealed no changes in the body weights, but there was a significant increase in fasting blood sugar levels in l-NAME - STZ-induced hypertensive-diabetes, which were lowered by losartan + metformin, losartan + glibenclamide, and losartan + metformin + glibenclamide treatments. Moreover, the increased systolic-BP, mean arterial pressure but not diastolic-BP and heart rate by l-NAME + STZ were attenuated more significantly by losartan + metformin + glibenclamide between weeks 2-8 relative to hypertensive-diabetic control. l-NAME + STZ-induced elevated levels of lactate dehydrogenase and creatinine kinase, were differentially reversed by losartan + metformin, losartan + glibenclamide, and losartan + metformin + glibenclamide. However, l-NAME + STZ-induced decreased nitrite level was significantly restored by all treatments, suggesting increased nitrergic transmission. Additionally, l-NAME + STZ-induced degeneration of pancreatic islet and myocardial cells were dramatically alleviated by losartan + metformin + glibenclamide treatments. Our findings suggest hyperglycemia with raised systolic-BP should be managed with losartan combined with both metformin and glibenclamide than single combination of losartan with antidiabetics.

Streptozotocin-Induced Type 1 and 2 Diabetes Mellitus Mouse Models Show Different Functional, Cellular and Molecular Patterns of Diabetic Cardiomyopathy.

The main cause of morbidity and mortality in diabetes mellitus (DM) is cardiovascular complications. Diabetic cardiomyopathy (DCM) remains incompletely understood. Animal models have been crucial in exploring DCM pathophysiology while identifying potential therapeutic targets. Streptozotocin (STZ) has been widely used to produce experimental models of both type 1 and type 2 DM (T1DM and T2DM). Here, we compared these two models for their effects on cardiac structure, function and transcriptome. Different doses of STZ and diet chows were used to generate T1DM and T2DM in C57BL/6J mice. Normal euglycemic and nonobese sex- and age-matched mice served as controls (CTRL). Immunohistochemistry, RT-PCR and RNA-seq were employed to compare hearts from the three animal groups. STZ-induced T1DM and T2DM affected left ventricular function and myocardial performance differently. T1DM displayed exaggerated apoptotic cardiomyocyte (CM) death and reactive hypertrophy and fibrosis, along with increased cardiac oxidative stress, CM DNA damage and senescence, when compared to T2DM in mice. T1DM and T2DM affected the whole cardiac transcriptome differently. In conclusion, the STZ-induced T1DM and T2DM mouse models showed significant differences in cardiac remodeling, function and the whole transcriptome. These differences could be of key relevance when choosing an animal model to study specific features of DCM.

Chinese herbal compound Jinsiwei improves synaptic plasticity in mice with sporadic Alzheimer's disease induced by streptozotocin.

OBJECTIVE: To investigate the efficacy of Jinsiwei (a patented Chinese herbal compound) on learning and memory impairment, the number of synapses and synaptic plasticity-related structural and functional protein expression in mice with sporadic Alzheimer's disease (SAD) induced by streptozotocin. METHODS: Seventy-five C57/BL6J male mice were intracerebroventricularly injected with streptozotocin to establish the animal model of SAD. Mice were randomly divided into the model group (MG), donepezil group (DG), and the Jinsiwei high, medium, and low-dose groups (JH, JM, JL). Another fifteen C57/BL6J male mice were injected with artificial cerebrospinal fluid as the control group (CG). The intervention groups were intragastrically administrated with corresponding medicine, while the CG and MG were given 0.5% carboxymethyl cellulose by gavage. After 3 months, the Morris Water Maze test and step-down passive avoidance test were used to assess the learning and memory ability of mice. Synapses in hippocampal CA1 were observed by transmission electron microscope. Immunohistochemistry and western blotting were used to assess the distribution and expression levels of synaptic plasticity-related structural and functional proteins involving drebrin, cofilin, synapsin (syn), and N-methyl D-aspartate receptor subtype 2B (NR2B). RESULTS: The Morris Water Maze results showed that the escape latency in the Jinsiwei intervention groups was significantly shorter than that of the MG. Results of the step-down passive-avoidance test showed that the error times in the Jinsiwei intervention groups were significantly reduced compared with the MG. Transmission electron microscope results showed that the number of synapses in hippocampal CA1 was obviously increased in the Jinsiwei intervention groups compared with the MG. Immunohistochemical and western blotting results revealed that the positive cells and expression levels of drebrin, syn, and NR2B were significantly decreased in the MG and meanwhile cofilin significantly increased, while these changes were reversed after the Jinsiwei treatment. CONCLUSIONS: Jinsiwei can alleviate learning and memory impairments in a mouse model of SAD, increase the number of synapses and enhance synaptic plasticity rescuing the expression of drebrin, syn, and NR2B and inhibiting cofilin expression.

A high-sucrose diet exacerbates the left ventricular phenotype in a high fat-fed streptozotocin rat model of diabetic cardiomyopathy.

Left ventricular (LV) dysfunction is an early, clinically detectable sign of cardiomyopathy in type 2 diabetes mellitus (T2DM) that precedes the development of symptomatic heart failure. Preclinical models of diabetic cardiomyopathy are essential to develop therapies that may prevent or delay the progression of heart failure. This study examined the molecular, structural, and functional cardiac phenotype of two rat models of T2DM induced by a high-fat diet (HFD) with a moderate- or high-sucrose content (containing 88.9 or 346 g/kg sucrose, respectively), plus administration of low-dose streptozotocin (STZ). At 8 wk of age, male Sprague-Dawley rats commenced a moderate- or high-sucrose HFD. Two weeks later, rats received low-dose STZ (35 mg/kg ip for 2 days) and remained on their respective diets. LV function was assessed by echocardiography 1 wk before end point. At 22 wk of age, blood and tissues were collected postmortem. Relative to chow-fed sham rats, diabetic rats on a moderate- or high-sucrose HFD displayed cardiac reactive oxygen species dysregulation, perivascular fibrosis, and impaired LV diastolic function. The diabetes-induced impact on LV adverse remodeling and diastolic dysfunction was more apparent when a high-sucrose HFD was superimposed on STZ. In conclusion, a high-sucrose HFD in combination with low-dose STZ produced a cardiac phenotype that more closely resembled T2DM-induced cardiomyopathy than STZ diabetic rats subjected to a moderate-sucrose HFD.NEW & NOTEWORTHY Left ventricular dysfunction and adverse remodeling were more pronounced in diabetic rats that received low-dose streptozotocin (STZ) and a high-sucrose high-fat diet (HFD) compared with those on a moderate-sucrose HFD in combination with STZ. Our findings highlight the importance of sucrose content in diet composition, particularly in preclinical studies of diabetic cardiomyopathy, and demonstrate that low-dose STZ combined with a high-sucrose HFD is an appropriate rodent model of cardiomyopathy in type 2 diabetes.

"Multiomics" Analyses Combined with Systems Pharmacology Reveal the Renoprotection of Mangiferin Monosodium Salt in Rats with Diabetic Nephropathy: Focus on Improvements in Renal Ferroptosis, Renal Inflammation, and Podocyte Insulin Resistance.

We explored the protection of mangiferin monosodium salt (MGM) on kidney injury in rats with streptozotocin (STZ)-induced diabetic nephropathy (DN) by "multiomics" analysis combined with systems pharmacology, with a specific focus on ferroptosis, inflammation, and podocyte insulin resistance (IR) signaling events in kidneys. MGM treatment afforded renoprotective effects on rats with STZ-induced DN by alleviating systemic IR-induced renal inflammation and podocyte IR. These mechanisms were correlated mainly with the MGM treatment-induced inhibition of the mitogen-activated protein kinase/nuclear factor-kappa B axis and activation of the phosphorylated insulin receptor substrate 1(Tyr608)/phosphorylated phosphatidylinositol 3-kinase/phosphorylated protein kinase B axis in the kidneys of DN rats. MGM had an ameliorative function in renal ferroptosis in rats with STZ-induced DN by upregulating mevalonate-mediated antioxidant capacities (glutathione peroxidase 4 and ferroptosis suppressor protein 1/coenzyme Q10 axis) and weakening acyl-CoA synthetase long-chain family member 4-mediated proferroptotic generation of lipid drivers in kidneys. MGM may be a promising alternative strategy for the treatment of DN.

Ketogenic diet modulates cardiac metabolic dysregulation in streptozocin-induced diabetic rats.

The ketogenic diet (KD) might improve cardiac function in diabetic cardiomyopathy, but the mechanisms remain unclear. This study investigated the effects of KD on myocardial fatty acid (FA), glucose, and ketone metabolism in diabetic cardiomyopathy. Echocardiograms, biochemistry, and micro-positron emission tomography were performed to evaluate cardiac function and glucose uptake in control rats and streptozotocin-induced diabetes mellitus (DM) rats with normal diet (ND) or KD for 6 weeks. Histopathology, adenosine triphosphate measurement, and Western blot were performed in the ventricular myocytes to analyze fibrosis, FA, ketone body, and glucose utilization. The ND-fed DM rats exhibited impaired left ventricular systolic function and increased chamber dilatation, whereas control and KD-fed DM rats did not. The KD reduced myocardial fibrosis and apoptosis in the DM rats. Myocardial glucose uptake in the micro-positron emission tomography was similar between ND-fed DM rats and KD-fed DM rats and was substantially lower than the control rats. Compared with the control rats,  ND-fed DM rats had increased phosphorylation of acetyl CoA carboxylase and higher expressions of CD-36, carnitine palmitoyltransferase-1ß, tumor necrosis factor-α, interleukin-1ß, interleukin6, PERK, and e-IF2α as well as more myocardial fibrosis and apoptosis (assessed by Bcl-2, BAX, and caspase-3 expression); these increases were attenuated in the KD-fed DM rats. Moreover, ND-fed DM rats had significantly lower myocardial adenosine triphosphate, BHB, and OXCT1 levels than the control and KD-fed DM rats. The KD may improve the condition of diabetic cardiomyopathy by suppressing FA metabolism, increasing ketone utilization, and decreasing endoplasmic reticulum stress and inflammation.

Is losartan a promising agent for the treatment of type 1 diabetes-induced testicular germ cell apoptosis in rats?

BACKGROUND: Diabetes mellitus (DM) is common metabolic disease that poses a major risk to public health and fertility. Previous studies indicate that DM may cause male infertility by triggering oxidative stress and germ cell apoptosis in the testis. Due to the undesirable effects of known antidiabetic drugs, scientists have begun to investigate the use of alternative drugs to control infertility complications observed in men. In this context, present study aimed to investigate the possible antiapoptotic effect of losartan against DM-induced testicular germ cell apoptosis. METHODS AND RESULTS: Expreimental DM model was induced by intraperitoneal injection of streptozocin (STZ, 55 mg/kg) to 28 rats, which were then randomly assigned to 4 groups; 1 mL saline solution was given to DM + saline group by oral gavage, 5 mg/kg/day oral losartan was given to DM + low-dose losartan, 20 mg/kg/day oral losartan was given to DM + mid-dose losartan and, 80 mg/kg/day oral losartan was given to DM + high-dose losartan group for 4 weeks. Bax, Bcl-2 and cleaved-Caspase 3 immunoexpression, terminal-deoxynucleotidyl transferase dutp nick end labeling (TUNEL), Annexin-V and Real Time PCR analyses performed to evaluate antiapoptotic effects of losartan on diabetic rats' testis. In addition, biochemical analyzes carried out to evaluate change in oxidative stress. CONCLUSION: The results showed that losartan may have dose-related antiapoptotic effects on rats' testis via decreasing oxidative stress.

Streptozotocin-induced Alzheimer's disease investigation by one-dimensional plasmonic grating chip.

Recently, there has been significant interest in researching brain insulin resistance as it has been hypothesized that it may play a role in the progression of Alzheimer's disease. Alzheimer's disease (AD) is brain dementia that contributes to damage to the neuron cells and then patient death. This dementia is ranked as the fifth more dangerous disease in the world. Streptozotocin (STZ) is used to induce Alzheimer's disease experimentally. STZ is toxic to the pancreatic beta cells and induces insulin resistance. Neuroplasmonin techniques have been used to investigate the ability of STZ on the activity of cultured neuron cells. Neuroplasmonic is a novel technology that combines nanotechnology and biosensor. This technique has been used to record neuron signals in vivo and in vitro. Also, it has many facilities such as label-free detection, real-time analysis, biological compatibility, small sample, high throughput, and low detection limit. In this paper, we introduce a one-dimensional electro-plasmonic nanograting platform that consists of a straight nanorod of gold embedded in a dielectric layer of polycarbonate. The chip is connected with an externally applied voltage to induce tunable PIT and increase the sensor sensitivity. To evaluate the sensing performance of the electro-plasmonic sensor, this chip was cultured with Human Nucleus Pulposus Cells (HNPC). The first step was to measure the neuron cell activity in a healthy case. The next step was to measure the activity of neuron cells injected with different concentrations of STZ (0.5, 1, 2 mM) to induce the formation of Alzheimer's disease in the cultured neuron cells. The results indicated that the electro-plasmonics sensor had a high sensitivity to the cells' activity and showed good results for the effecting STZ on the neuron cell's activities.

Dimethyl Fumarate Alleviates Adult Neurogenesis Disruption in Hippocampus and Olfactory Bulb and Spatial Cognitive Deficits Induced by Intracerebroventricular Streptozotocin Injection in Young and Aged Rats.

The disorder of adult neurogenesis is considered an important mechanism underlying the learning and memory impairment observed in Alzheimer's disease (AD). The sporadic nonhereditary form of AD (sAD) affects over 95% of AD patients and is related to interactions between genetic and environmental factors. An intracerebroventricular injection of streptozotocin (STZ-ICV) is a representative and well-established method to induce sAD-like pathology. Dimethyl fumarate (DMF) has antioxidant and anti-inflammatory properties and is used for multiple sclerosis treatment. The present study determines whether a 26-day DMF therapy ameliorates the disruption of adult neurogenesis and BDNF-related neuroprotection in the hippocampus and olfactory bulb (OB) in an STZ-ICV rat model of sAD. Considering age as an important risk factor for developing AD, this study was performed using 3-month-old (the young group) and 22-month-old (the aged group) male Wistar rats. Spatial cognitive functions were evaluated with the Morris water maze task. Immunofluorescent labelling was used to assess the parameters of adult neurogenesis and BDNF-related neuroprotection in the hippocampus and OB. Our results showed that the STZ-ICV evoked spatial learning and memory impairment and disturbances in adult neurogenesis and BDNF expression in both examined brain structures. In the aged animals, the deficits were more severe. We found that the DMF treatment significantly alleviated STZ-ICV-induced behavioural and neuronal disorders in both age groups of the rats. Our findings suggest that DMF, due to its beneficial effect on the formation of new neurons and BDNF-related neuroprotection, may be considered as a promising new therapeutic agent in human sAD.

Maternal care of the whole litter improves the success rate of diabetes in pregnancy in rats.

Induction of diabetes mellitus by streptozotocin (STZ) in rats at birth is of high mortality and low success rate when male puppies are separated from females, prioritizing females breastfeeding. Cross-parental care of the entire litter and SZT-induced diabetes up to 12 h post-birth become with high success rate, low animal death, and females with glycaemia >140 mg/dL on the 90 postnatal day. Cross-parental care is more effective in STZ-induction of diabetes, which is maintained during pregnancy (diabetes in pregnancy), than the conventional protocol of male separation at birth.

KLF9 Aggravates Streptozotocin-Induced Diabetic Cardiomyopathy by Inhibiting PPARγ/NRF2 Signalling.

AIMS: Krüppel-like Factor 9 (KLF9) is a transcription factor that regulates multiple disease processes. Studies have focused on the role of KLF9 in the redox system. In this study, we aimed to explore the effect of KLF9 on diabetic cardiomyopathy. METHODS AND RESULTS: Cardiac-specific overexpression or silencing of KLF9 in C57BL/6 J mice was induced with an adeno-associated virus 9 (AAV9) delivery system. Mice were also subjected to streptozotocin injection to establish a diabetic cardiomyopathy model. In addition, neonatal rat cardiomyocytes were used to assess the possible role of KLF9 in vitro by incubation with KLF9 adenovirus or small interfering RNA against KLF9. To clarify the involvement of peroxisome proliferator-activated receptors (PPARγ), mice were subjected to GW9662 injection to inhibit PPARγ. KLF9 was upregulated in the hearts of mice with diabetic cardiomyopathy and in cardiomyocytes. In addition, KLF9 overexpression in the heart deteriorated cardiac function and aggravated hypertrophic fibrosis, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. Conversely, cardiac-specific silencing of KLF9 ameliorated cardiac dysfunction and alleviated hypertrophy, fibrosis, the cardiac inflammatory response and oxidative stress. In vitro, KLF9 silencing in cardiomyocytes enhanced inflammatory cytokine release and oxidative stress; KLF9 overexpression increased these detrimental responses. Moreover, KLF9 was found to regulate the transcription of PPARγ, which suppressed the expression and nuclear translocation of nuclear Factor E2-related Factor 2 (NRF2). In mice injected with a PPARγ inhibitor, the protective effects of KLF9 knockdown on diabetic cardiomyopathy were counteracted by GW9662 injection. CONCLUSIONS: KLF9 aggravates cardiac dysfunction, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. KLF9 may become a therapeutic target for diabetic cardiomyopathy.

Long-term follow-up of intracerebroventricular injection of streptozotocin-inducing pain sensitization.

Age is known to be the major risk factor for both pain sensation and sporadic Alzheimer's disease (sAD). Pain management in AD is a critical health condition. However, assessing pain in sAD patients is challenging. The intracerebroventricularly injected streptozotocin (icv-STZ) rat model of sAD has been brought to the fore as a hopefully suitable model that could mimic some features of sAD. However, the exact mechanism by which this agent may induce AD-like pathology is largely unknown. In some studies, analgesic drugs have been suggested as possible prevention of AD and icv-STZ-induced AD-like pathology. Therefore, this study used formalin and tail-flick tests to investigate whether different doses of icv-STZ injections could affect acute and inflammatory pain sensation and edema volume over time. Behavioral responses were observed at four testing time points (1, 2.5, 3.5, and 6 months postinjection). The results indicate that icv-STZ was able to significantly decrease the animals' formalin pain threshold in both a time- and dose-dependent manner. Formalin-induced acute and chronic pain scores of animals treated with streptozotocin 3 mg/kg (STZ3) increased dramatically 2.5 months after injection and persisted thereafter. The augmentation in pain score induced by streptozotocin 1 mg/kg (STZ1) was observed from 3.5 months after STZ injection. However, the effect of streptozotocin 0.5 mg/kg (STZ0.5) was NS until 6 months after injection. However, formalin-induced paw edema occurred with a longer delay and was not detectable in STZ0.5-treated animals. In addition, only STZ3-treated animals significantly reduced the thermal pain threshold of animals 6 months after injection. These observations indicate that icv-STZ can sensitize central and/or peripheral receptors to pain. The effect of STZ is dose- and time-dependent. AD-like pathology induced by icv-STZ could be partially activated via pain processing pathways. Therefore, anti-inflammatory agents could alleviate AD-like symptoms via pain treatments.

Effect of Momordica charantia on Insulin Immune-Reactive Pancreatic Beta Cells and Blood Glucose Levels in Streptozotocin-Induced Diabetic Rats.

The present study was conducted to determine the antidiabetic effect of Momordica charantia (MC) on pancreatic islets of Langerhans in streptozotocin (STZ)-induced diabetic male Wistar rats in relation to the distribution of insulin immuno-positive beta cells. MC was fed to rats at 2, 5, and 10% of the standard diet for 12 wk. After sacrification, the pancreatic tissues were obtained for histopathological and immunohistochemical observations. In addition, monitoring of fasting blood glucose was applied each month during experimental period. The results revealed that the oral doses of MC at 5% and 10% of the daily diet increased the percentage of insulin-positive pancreatic beta cells as well as the size and number of pancreatic islets. Moreover, significant (p≤0.0001) dose and time-depended reduction in fasting blood glucose levels were observed. In conclusion, these results suggest that MC induces antidiabetic effects via regeneration of insulin-positive pancreatic beta cells and increase the number of insulin secretory granules hence, blood glucose reduction.

Local Application of Krill Oil Accelerates the Healing of Artificially Created Wounds in Diabetic Mice.

Diabetes mellitus (DM) impairs the wound healing process, seriously threatening the health of the diabetic population. To date, few effective approaches have been developed for the treatment of diabetic wounds. Krill oil (KO) contains bioactive components that have potent anti-inflammatory and anti-oxidative activities. As prolonged inflammation is a crucial contributor to DM-impaired wound healing, we speculated that the local application of KO would accelerate diabetic wound healing. Therefore, KO was applied to artificially created wounds of type 2 diabetic mice induced by streptozotocin and high-fat diet. The diabetic mice had a delayed wound healing process compared with the non-diabetic control mice, with excessive inflammation, impaired collagen deposition, and depressed neovascularization in the wound area. These effects were dramatically reversed by KO. In vitro, KO blocked the TNF-α-induced macrophage inflammation, fibroblast dysfunction, and endothelial angiogenic impairment. The present study in mice suggests that KO local application could be a viable approach in the management of diabetic wounds.