Diabetic cardiomyopathy in rats was attenuated by endurance exercise through the inhibition of inflammation and apoptosis.

Diabetic cardiomyopathy (DCM), as a ventricular dysfunction, is one of the main causes of death in diabetic patients. Former evidence revealed the beneficial effects of exercise on cardiovascular complications of diabetes. We aimed to investigate the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on DCM. Male Wistar rats were divided into control, diabetic, metformin (300 mg/kg), HIIT, MICT, metformin + HIIT, and metformin + MICT diabetic groups. Serum biochemical, inflammatory, and oxidative stress indicators, gene expression of BCL2 and BAX, and histopathologic changes of cardiac tissue were assessed. Our analysis revealed an increase in fasting blood sugar (FBS), creatine kinase MB (CK-MB), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) in diabetes. Also, the superoxide dismutase (SOD) and catalase (CAT) activity, and the total thiol were decreased, in contrast, malondialdehyde (MDA) levels increased in the cardiac tissue of the diabetic group. All of these changes were significantly ameliorated in diabetic animals treated with exercise and metformin + exercise. The level of tumor necrosis factor-α (TNF-α) and Interleukin-1ß (IL-1ß), as well as the infiltration of inflammatory cells, were decreased in the heart of all exercise training groups. Up-regulation of BCL2 and down-regulation of BAX gene expressions were observed in the cardiac tissue of all exercise-treated groups. In conclusion, HIIT and MICT exercises are effective in preventing DCM development. Exercise training, besides improving oxidative stress and inflammation in cardiac tissue, alleviates cardiac damage by modulating the apoptotic gene expression in diabetic rats.

The effects of endurance exercise and metformin on memory impairment caused by diabetes.

OBJECTIVES: Diabetes has a negative effect on learning and memory performance, and it is a risk factor for Alzheimer's disease and dementia development. The present study aims to investigate the effects of two kinds of endurance exercise including high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) as well as metformin on impaired memory and learning related to streptozotocin (STZ) induced diabetes in rats. METHODS: Forty adult male rats (250 ± 20 g weight) were divided into five groups (n=8), including control, diabetic, as well as diabetic rats treated with metformin (300 mg/kg), and HIIT (20 m/min), and MICT (15 m/min) exercises. Diabetes was induced by STZ (60 mg/kg, i.p.). Serum glucose concentration and oxidative stress markers (SOD, CAT, thiol, and MDA) in the cortex and hippocampus were determined by colorimetric assay. Behavioral tests were performed with a passive avoidance test. RESULTS: The diabetic groups treated with metformin and both HIIT, and MICT exercises improved the latency and the staying time in the darkroom and lightroom. The entrance frequency into the darkroom also was restored (p<0.01-p<0.001). In both HIIT and MICT exercises as well as metformin groups the oxidative stress induced by diabetes has been reversed and attenuation of the serum glucose level has been observed compared to non-treated diabetic ones (p<0.05-p<0.001). CONCLUSIONS: The results of the present study revealed both HIIT and MICT exercises had protective effects against oxidative stress and behavioral impairments induced by diabetes and these effects were comparable to the effects of metformin.

Protective effects of cinnamon on acetylcholinesterase activity and memory dysfunction in diabetic rats.

OBJECTIVES: Regarding neurocognitive and immunomodulatory properties of cinnamon (Cinn) we aimed to investigate whether cinnamon regulates acetylcholinesterase (AChE) activity, and oxidative abnormalities with concomitant memory dysfunction in streptozotocin (STZ)-induced diabetes. METHODS: Forty-seven male adult rats were divided into seven groups (n=8 animals): Control group: in these non-diabetic rats only saline 0.9% NaCl was gavaged, Diabetic (Dia) group: diabetic rats in them saline 0.9% NaCl was gavaged for six weeks. Dia-Cinn 100, Dia-Cinn 200, and Dia-Cinn 400, Dia-Met groups: in these diabetic rats the extract (100, 200, 400 mg/kg respectively) or metformin (300 mg/kg) was gavaged for six weeks. Passive avoidance performance, AChE enzyme activity, and oxidative indicators were examined among the groups. RESULTS: Vs. the control group, blood glucose level and stay time in the dark were remarkably increased in Dia group whereas the latency time was decreased. Meanwhile, antioxidant levels (superoxide dismutase, catalase, and thiols) noticeably decreased in the Dia group compared to the Control group. On the other hand, Cinn extract espicailly at the highest dose recovered the changes similar to those found in the metformin-treated group. CONCLUSIONS: These findings proposed that the cinnamon hydro-ethanolic extract promotes memory recovery in diabetic conditions through the atteuation of the AChE activity and oxidative injury.

Cardiac hypertrophy and fibrosis were attenuated by olive leaf extract treatment in a rat model of diabetes.

The key role of fibrosis and hypertrophy processes in developing diabetes-induced heart injury has been demonstrated. Considering the known hypoglycemic effects of olive leaf extract (OLE), we decided to investigate its potential effect and associated mechanisms on cardiac fibrosis and myocardial hypertrophy in streptozotocin (STZ)-induced diabetic rats. Eight groups were included in this study: control, diabetic, diabetic-OLEs (100, 200 and 400 mg/kg), diabetic-metformin (300 mg/kg), diabetic-valsartan (30 mg/kg), and diabetic-metformin/valsartan (300/30 mg/kg). After a treatment period of 6 weeks, echocardiography was used to assess cardiac function. Heart-to-body weight ratio (HW/BW) and fasting blood sugar (FBS) were measured. Myocardial histology was examined by Masson's trichrome staining. Gene expressions of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), ß-myosin heavy chain (ß-MHC), TGF-ß1, TGF-ß3, angiotensin II type 1 receptor (AT1), alpha-smooth muscle actin (α-SMA), and collagen were evaluated by the quantitative real-time PCR in heart tissue. A reduction in the FBS level and HW/BW ratio in the extract groups was obvious. The improvement of left ventricular dysfunction, cardiac myocytes hypertrophy, and myocardial interstitial fibrosis was also observed in treated groups. A lowering trend in the expression of all hypertrophic and fibrotic indicator genes was evident in the myocardium of OLE treated rats. Our data indicated that OLE could attenuate fibrosis and reduce myocardial hypertrophy markers, thus improving the cardiac function and structure in the STZ-induced diabetic rats. PRACTICAL APPLICATIONS: This study demonstrates that olive leaf extract in addition to lowering blood glucose levels and the heart-to-body weight ratio (HW/BW) may also improve cardiac function and reduce cardiac hypertrophy and fibrosis in cardiac tissue, which leads to inhibition of diabetic heart damage. Thus it is possible that including olive leaf extracts in the diets of individuals with diabetes may assist in lowering cardiovascular disease risk factors.

Olea europaea L. (olive) leaf extract ameliorates learning and memory deficits in streptozotocin-induced diabetic rats.

Objective: The aim of the present study was to assess olive leaf extract (OLE) effects on learning and memory deficits in a model of diabetes induced by streptozotocin (STZ) in rats. Materials and methods: The rats were divided as: (1) control rats, (2) diabetic rats, and (3-6) diabetic rats treated by 100, 200, and 400 mg/kg of OLE or metformin. Using the passive avoidance test (PA), we investigated fear learning and memory behaviors. In cortical and hippocampus tissues, total levels of malondialdehyde (MDA) and thiol were measured along with the activity of catalase (CAT) and superoxide dismutase (SOD). Results: Learning and memory behavior impairment were significantly developed in diabetic rats as shown by the impairment of the PA task compared to the control group (p<0.001). In addition, elevated levels of MDA and reduced overall concentrations of thiol, CAT and SOD activity were obvious in diabetic rats' cortex and hippocampus tissues (p<0.01-p<0.001). Meanwhile, OLE in a dose-dependent manner, improved memory deficit and cognitive performance that was attributed to a reduction of lipid peroxidation and elevation of total thiol concentration, and CAT and SOD activity levels in the brain tissues (p<0.05-p<0.001). Conclusion: OLE could be effective in improving cognitive impairment in STZ-induced diabetes by oxidative stress depression.

Anti-inflammatory, anti-oxidant and anti-apoptotic effects of olive leaf extract in cardiac tissue of diabetic rats.

OBJECTIVES: Inflammatory process and apoptosis are involved in the pathogenesis of cardiac injury and oxidative damage caused by diabetes mellitus. The cardioprotective effects of standardized aqueous ethanolic olive leaf extract (OLE), metformin (as a cardiovascular protective agent) and valsartan (as an angiotensin receptor blocker) in the streptozotocin-induced diabetic rats were evaluated. METHODS: Wistar rats divided into control, diabetic, OLE-treated (100, 200 and 400 mg/kg), metformin (300 mg/kg)-treated, valsartan (30 mg/kg)-treated and metformin/valsartan-treated diabetic groups. Biochemical parameters, including malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activates, and the total contents of thiol were measured, and histopathological and gene expression studies were done on cardiac tissues. Fasting blood sugar (FBS) and cardiac injury markers were examined in serum. KEY FINDINGS: FBS; the serum levels of lactate dehydrogenase (LDH), creatine kinase-muscle/brain (CK-MB), aspartate aminotransferase (AST); and heart tissue MDA levels due to diabetes were significantly alleviated by OLE treatment (effect size; ηp2 = 0.934, 0.888, 0.848, 0.888 and 0.879, respectively), and SOD and CAT activity and the thiol content in heart tissue were significantly increased (effect size; ηp2 = 0.770, 0.749 and 0.753, respectively). Interleukin-1ß (IL-1ß), tumour necrosis factor-α (TNF-α) and the number of infiltrating inflammatory cells were reduced in cardiac tissues of OLE-treated groups compared with the diabetic rats (effect size; ηp2 = 0.969 and 0.949, respectively). OLE up-regulated BCL2 gene expression and down-regulated BAX gene expression in cardiac tissue (effect size; ηp2= 0.490 and 0.522, respectively). CONCLUSION: OLE in a dose-dependent manner ameliorates cardiac damage in diabetic cardiomyopathy, perhaps through attenuating inflammation, oxidative stress and apoptosis.

Diabetic cardiomyopathy was attenuated by cinnamon treatment through the inhibition of fibro-inflammatory response and ventricular hypertrophy in diabetic rats.

Diabetic cardiomyopathy (DCM) is a chronic complication of diabetes that emphasizes the urgency of developing new drug therapies. With an illustrious history in traditional medicine to improve diabetes, cinnamon has been shown to possess blood lipids lowering effects and antioxidative and anti-inflammatory properties. However, the extent to which it protects the diabetic heart has yet to be determined. Forty-eight rats were administered in the study and grouped as: control; diabetic; diabetic rats given 100, 200, or 400 mg/kg cinnamon extract, metformin (300 mg/kg), valsartan (30 mg/kg), or met/val (combination of both drugs), via gavage for six weeks. Fasting blood sugar (FBS) and markers of cardiac injury including creatine kinase-muscle/brain (CK-MB), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were evaluated in blood samples. Malondialdehyde (MDA) levels, the total contents of thiol, superoxide dismutase (SOD), and catalase (CAT) activities were measured. Histopathology study and gene expression measurement of angiotensin II type 1 receptor (AT1), atrial natriuretic peptide (ANP), beta-myosin heavy chain (ß-MHC), and brain natriuretic peptide (BNP) were done on cardiac tissue. FBS and cardiac enzyme indicators were reduced in all treated groups. A reduction in MDA level and enhancement in thiol content alongside with increase of SOD and CAT activities were observed in extract groups. The decrease of inflammation and fibrosis was obvious in treated groups, notably in the high-dose extract group. Furthermore, all treated diabetic groups showed a lowering trend in AT1, ANP, ß-MHC, and BNP gene expression. Cinnamon extract, in addition to its hypoglycemic and antioxidant properties, can prevent diabetic heart damage by alleviating cardiac inflammation and fibrosis. PRACTICAL APPLICATIONS: This study found that cinnamon extract might protect diabetic heart damage by reducing inflammation and fibrosis in cardiac tissue, in addition to lowering blood glucose levels and increasing antioxidant activity. Our data imply that including cinnamon in diabetic participants' diets may help to reduce risk factors of cardiovascular diseases.

Valproic Acid attenuates disease symptoms and increases endogenous myelin repair by recruiting neural stem cells and oligodendrocyte progenitors in experimental autoimmune encephalomyelitis.

BACKGROUND: inefficient remyelination of demyelinated plaques in multiple sclerosis (ms) leads to secondary axon degeneration and progressive disability. therapies that potentiate remyelination would be of immense help for managing MS. OBJECTIVE: Here, we report the effects of valproic acid (VPA) on focal experimental autoimmune encephalomyelitis (fEAE). METHODS: fEAE was induced in Wistar rats by immunizing the animals with guinea pig spinal cord homogenate emulsified in complete Freund's adjuvant and with pertussis toxin (PT) injection into the spinal cord at the level of T8 vertebra on day 18 after immunization. VPA 300 mg/kg was applied for 4 days after or 8 days before PT administration. Behavioral evaluation, histological assessment and immunohistofluorescence assays were used to evaluate the outcomes. RESULTS: VPA administration had no effect on the development of symptoms, but after discontinuing VPA, animals showed faster recovery. Eight days of pretreatment with VPA accelerated the recovery phase of EAE and increased the number of remyelinated axons in the lesion area. VPA pretreatment also increased the recruitment of neural stem cells and oligodendrocyte precursors within the lesion. CONCLUSIONS: Results suggest VPA as a potential therapy for remyelinating the lesions in MS and for faster recovery from disease relapses. The effect of VPA seems to be mediated by endogenous progenitors recruitment.

Adenosine A1 receptor agonist, N6-cyclohexyladenosine, protects myelin and induces remyelination in an experimental model of rat optic chiasm demyelination; electrophysiological and histopathological studies.

Chronic demyelinated lesions and subsequent functional impairment are resulted from eventual failure of remyelination process as seen in multiple sclerosis. Activation of adenosine A1 receptor is reported to be effective on neural stem cells (NSCs) proliferation and oligodendrocytes differentiation. Therefore, this study attempted to investigate the effect of A1 receptor agonist N6-cyclohexyladenosine (CHA), on lysolecithin (LPC) induced demyelination and remyelination in rat optic chiasm. The experiments were carried out on male Wistar rats using visual evoked potential recording, myelin staining by Luxol fast blue and histological evaluation of demyelinated and remyelinated axons within the area of lesion. CHA was administrated i.c.v. during demyelination or remyelination phases. As revealed by myelin staining, the most extent of demyelination occurred at 7th day post-lesion (dpl 7), but gradually myelination was restored toward control during days 14-28. VEP P1-latency and P1-N1 amplitude showed widespread demyelination on dpl 7 and 14 which consequently was reversed during days 14-28 post lesion. I.c.v. treatment of animals with CHA during demyelination phase (days 0-13) reduced the extent of demyelination. During remyelination phase (days 14-28), CHA was able to increase remyelination in both electrophysiological and histopathological studies. The effects of CHA seem to be due to its protective effect on myelinating cells and its regenerative effect through potentiating endogenous neural progenitors.