Exercise augments the modulatory effects of vitamin E on pre-diabetes-induced aortopathy: a potential role of adiponectin

Background: We tested the hypothesis that vitamin E may protect against pre-diabetes-induced aortic injury (aortopathy), and exercise can augment the action of vitamin E.Material and methods: Rats were either fed with a high fat and fructose diet (HFD) (model group) or a standard laboratory chow (control group) for 15 weeks before being sacrificed. The three protective groups were treated with vitamin E (HFD + Vit E), swimming exercises (HFD + Ex), and vitamin E plus swimming exercises (HFD + VitE + Ex), respectively.Results: Aortopathy was developed in the model group as demonstrated by substantial tissue ultrastructural alterations, which were partially protected by vitamin E and effectively protected with vitamin E plus swim exercise. Also, swimming exercises significantly (p < .05) increased the modulatory effects of vitamin E on dyslipidemia, insulin resistance, blood pressure, oxidative stress, inflammation, leptin, and adiponectin, except coagulation and thrombosis.Conclusions: Swim exercise augments the protective effects of vitamin E in a pre-diabetic animal model.

Suppression of type 2 diabetes mellitus-induced aortic ultrastructural alterations in rats by insulin: an association of vascular injury biomarkers

Diabetes represents a major public health problem and an estimated 70% of people with diabetes die of cardiovascular complications. The protective effect of insulin treatment against ultrastructural damage to the tunica intima and tunica media of the aorta induced by type 2 diabetes mellitus (T2DM) has not been investigated before using transmission electron microscopy (TEM). Therefore, we induced T2DM in rats using high fat diet and streptozotocin (50 mg/kg) and administered insulin daily by i.v injection for 8 weeks to the treatment group. Whereas, the T2DM control group were left untreated for the duration of the experiment. A comparison was also made between the effect of insulin on aortic tissue and the blood level of biomarkers of vascular injury, inflammation, and oxidative stress. T2DM induced profound ultrastructural damage to the aortic endothelium and vascular smooth muscle cells, which were substantially protected with insulin. Furthermore, insulin returned blood sugar to a control level and significantly (p < .05) inhibited diabetic up-regulation of endothelial and leukocyte intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion protein 1 (VCAM-1), endothelial cell adhesion molecules, P-selectin and E-selectin, tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and malondialdehyde (MDA). Furthermore, insulin augmented the blood level of the anti-oxidant enzyme superoxide dismutase (SOD). We conclude that in a rat model of T2DM, insulin treatment substantially reduces aortic injury secondary to T2DM for a period of 8 weeks, possibly due to the inhibition of hyperglycemia, vascular activation, inflammation, and oxidative stress.

Metformin pretreatment suppresses alterations to the articular cartilage ultrastructure and knee joint tissue damage secondary to type 2 diabetes mellitus in rats

Osteoarthritis (OA) secondary to diabetes affects millions of people worldwide and can lead to disability. The protective effect of metformin pretreatment against alterations to the articular cartilage ultrastructure induced by type 2 diabetes mellitus (T2DM) associated with the inhibition of oxidative stress and inflammation has not been investigated before. Therefore, we induced T2DM in rats (the model group) using high carbohydrate and fat diet and a single injection of streptozotocin (50 mg/kg body weight). The protective group of rats started metformin (200 mg/kg body weight) treatment 14 days before diabetic induction and continued on metformin until the end of the experiment at week 12. Harvested tissues obtained from knee joints were prepared for staining with hematoxylin and eosin (H&E), safranin o staining, and electron microscopy. Histology images showed that OA was developed in the T2DM rats as demonstrated by a substantial damage to the articular cartilage and profound chondrocyte and territorial matrix ultrastructural alterations, which were partially protected by metformin. In addition, metformin significantly (p < .05) reduced hyperglycemia, glycated hemoglobin (HbA1 c), malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), and interleukin-6 blood levels induced by diabetes. Furthermore, a significant (p ≤ 0.015) correlation between either OA cartilage grade score or the thickness of the articular cartilage and the blood levels of HbA1 c, hs-CRP, MDA, superoxide dismutase (SOD) were observed. These findings demonstrate effective protection of the articular cartilage by metformin against damage induced secondary to T2DM in rats, possibly due to the inhibition of hyperglycemia and biomarkers of oxidative stress and inflammation.

Suppression of glomerular damage and apoptosis and biomarkers of acute kidney injury induced by acetaminophen toxicity using a combination of resveratrol and quercetin

Acute renal failure induced by a toxic dose of acetaminophen (also known as paracetamol, or APAP) is common in both humans and experimental animal models. Glomerular ultrastructural alterations induced by APAP overdose associated with the suppression of biomarkers of kidney injury have not been investigated before. Also, we investigated whether the combined polyphenolic antioxidants and anti-inflammatory compounds, resveratrol (RES) and quercetin (QUR) can protect against APAP-induced nephrotoxicity. Rats either received a single dose of APAP (2 g/kg) before being sacrificed after 24 hours or were pretreated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP and then sacrificed 24 hours post APAP ingestion. APAP significantly (p < 0.05) increased blood levels of urea, creatinine, malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), which were effectively reduced by RES + QUR. In addition, APAP overdose induced the tissue expression of the apoptotic biomarker, p53, and caused profound kidney damage as demonstrated by substantial alterations to the glomerular basement membrane, podocytes, endothelial cells, widening of Bowman's space, and vacuolation of the cells lining the parietal layer, which were substantially protected by RES + QUR. Furthermore, a significant (p < 0.0001) positive correlation was observed between either glomerular basement membrane or podocyte foot processes and these parameters, urea, creatinine, MDA, and TNF-α. Thus, we conclude that APAP induces alterations to the glomerulus ultrastructure, which is protected by resveratrol plus quercetin, which also reduces blood levels of urea and creatinine, and biomarkers of oxidative stress and inflammation.

Homocysteine and Hyperhomocysteinaemia

Homocysteine (Hcy) is a thiol group containing the amino acid, which naturally occurs in all humans. Hcy is degraded in the body through two metabolic pathways, while a minor part is excreted through kidneys. The chemical reactions that are necessary for degradation of Hcy require the presence of folic acid, vitamins B6 and B12. Consequently, the level of the total Hcy in the serum is influenced by the presence or absence of these vitamins. An elevated level of the Hcy, hyperhomocysteinemia (HHcy) and homocystinuria is connected with occlusive artery disease, especially in the brain, the heart, and the kidney, in addition to venous thrombosis, chronic renal failure, megaloblastic anemia, osteoporosis, depression, Alzheimer's disease, pregnancy problems, and others. Elevated Hcy levels are connected with various pathologies both in adult and child population. Causes of HHcy include genetic mutations and enzyme deficiencies in 5, 10-methylenetetrahydrofolate reductase (MTHFR) methionine synthase (MS), and cystathionine β-synthase (CβS). HHcy can be caused by deficiencies in the folate, vitamin B12 and to a lesser extent, deficiency in B6 vitamin what influences methionine metabolism. Additionally, HHcy can be caused by the rich diet and renal impairment. This review presents literature data from recent research related to Hcy metabolism and the etiology of the Hcy blood level disorder. In addition, we also described various pathological mechanisms induced by hereditary disturbances or nutritional influences and their association with HHcy induced pathology in adults and children and treatment of these metabolic disorders.

Suppression of acetaminophen-induced hepatocyte ultrastructural alterations in rats using a combination of resveratrol and quercetin

Ingestion of a toxic dose of the analgesic drug, acetaminophen (also called paracetamol or APAP), is among the most common causes of acute liver injury in humans. We tested the hypothesis that the combined polyphenolic compounds, resveratrol (RES) and quercetin (QUR), can substantially protect against hepatocyte ultrastructural damage induced by a toxic dose of APAP in a rat model of APAP-induced acute liver injury. The model group of rats received a single dose of APAP (2 g/kg), whereas the protective group of rats was pretreated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP. All rats were then sacrificed 24 hours post APAP ingestion. Harvested liver tissues were prepared for transmission electron microscopy (TEM) staining, and liver homogenates were assayed for biomarkers of inflammation, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and oxidative stress, such as malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx). In addition, blood samples were assayed for the liver injury enzyme alanine aminotransferase (ALT) as an indicator of liver damage. TEM images showed that APAP overdose induced acute liver injury as demonstrated by profound hepatocyte ultrastructural alterations, which were substantially protected by RES+QUR. In addition, APAP significantly (p < 0.05) modulated TNF-α, IL-6, MDA, SOD, GPx, and ALT biomarkers, which were completely protected by RES+QUR. Thus, RES+QUR effectively protects against APAP-induced acute liver injury in rats, possibly via the inhibition of inflammation and oxidative stress.

Resveratrol Pretreatment Ameliorates p53-Bax Axis and Augments the Survival Biomarker B-Cell Lymphoma 2 Modulated by Paracetamol Overdose in a Rat Model of Acute Liver Injury

Background: The potential protective effects of resveratrol (RES) on the modulation of hepatic biomarkers of apoptosis and survival, p53-Bax axis, and B-cell lymphoma 2 (Bcl-2) in an animal model of paracetamol-induced acute liver injury have not been investigated before. Methods: The model group of rats received a single dose of paracetamol (2 g/kg, orally), whereas the protective group of rats were pretreated for 7 days with RES (30 mg/kg, i.p.) before they were given a single dose of paracetamol. All rats were then sacrificed 24-h post paracetamol ingestion. Results: Histology images showed that paracetamol overdose induced acute liver injury, which was substantially protected by RES. Paracetamol significantly (p < 0.05) modulated p53, apoptosis regulator Bax, Bcl-2, tumor necrosis factor-alpha, interleukin-6, inducible nitric oxide synthase, malondialdehyde, superoxide dismutase, glutathione peroxidase, alanine aminotransferase, and aspartate aminotransferase, which were significantly protected by RES. We further demonstrated a significant (p< 0.01) correlation between either p53 or Bcl-2 scoring and the levels of inflammatory, nitrosative stress, and liver injury biomarkers. Conclusion: We demonstrate a substantial protection by RES pretreatment against paracetamol-induced modulation of p53-Bax axis, Bcl-2, and other acute liver injury biomarkers in rats.

Metformin suppresses aortic ultrastrucural damage and hypertension induced by diabetes: a potential role of advanced glycation end products

Cardiovascular disease secondary to diabetes represents a significant challenge to the health community. The advanced glycation end products (AGEs) play an important role in diabetes-mediated vascular injury. We tested whether metformin can suppress aortic AGEs production and protect against aortic injuries (aortopathy) and hypertension in streptozotocin-induced type 2 diabetes mellitus (T2DM) animal model. T2DM was induced in rats two weeks after being fed on a high carbohydrate and fat diet (HCFD), and continued on a HCFD until being sacrificed at week 12 (model group). The protective group was put on metformin two weeks before diabetic induction and continued on metformin and HCFD until the end of the experiment, at week 12. Using electron microscopy examinations, we observed in the model group substantial damage to the ultrastructure of aortic endothelial and vascular smooth muscle layers as demonstrated by markedly distorted vacuolated endothelial and vascular smooth muscle cells with pyknotic nuclei detached from the underlying basement membrane, which were protected by metformin. Also, metformin significantly (p < .05) decreased both systolic and diastolic blood pressure, aortic levels of AGEs, and blood levels of oxidative stress and inflammatory biomarkers. We conclude that metformin protects against T2DM-induced aortopathy and hypertension, possibly via the inhibition of AGEs, inflammation, and oxidative stress.

Vitamin E ameliorates alterations to the articular cartilage of knee joints induced by monoiodoacetate and diabetes mellitus in rats

We recently reported an animal model of osteoarthritis (OA) induced by a combination of the chondrocyte glycolysis inhibitor, monoiodoacetate (MIA) and the agent that induces diabetes mellitus, streptozotocin (STZ). Here we investigated the potential protective effect of the antioxidant and anti-inflammatory agent, vitamin E against MIA+STZ-induced OA. Therefore, rats were either injected once with MIA (2 mg/50 μL) + 65 mg/kg STZ before being sacrificed after 8 weeks (model group) or were treated immediately after MIA+STZ injections with vitamin E (600 mg/kg; thrice a week) before being sacrificed after 8 weeks (treatment group). Using scanning and transmission electron microscopy examinations, we observed in the model group a substantial damage to the articular cartilage of the knee joint as demonstrated by the destruction of the chondrocytes, territorial matrix, disrupted lacunae, collagen fibers, and profound chondrocyte ultrastructural alterations such as degenerated chondrocyte, irregular cytoplasmic membrane, damaged mitochondria and rough endoplasmic reticulum, vacuolated cytoplasm, presence of lipid droplets and different sizes of lysosomes, which were substantially but not completely protected by vitamin E. H&E stained sections of knee joint articular cartilage showed that MIA+STZ induced damage to the chondrocyte and territorial matrix. Vitamin E also significantly (p < .05) inhibited MIA+STZ-induced blood levels of the inflammatory biomarkers, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) that are known to be modulated in OA and diabetes. We conclude that vitamin E protects against MIA+STZ-induced knee joints injuries in rats, which is associated with the inhibition of biomarkers of inflammation.

Insulin Suppresses Type 1 Diabetes Mellitus-Induced Ventricular Cardiomyocyte Damage Associated with the Inhibition of Biomarkers of Inflammation and Oxidative Stress in Rats

Aims: We sought to determine whether insulin can protect against type 1 diabetes mellitus (T1DM)-induced cardiac ultrastructural alterations in an animal model of the disease. This has not been investigated before. Methods: Rats were either injected once with 65 mg/kg streptozotocin (STZ) before being sacrificed after 8 weeks or were treated with a daily injection of insulin 2 days by STZ and continued until being sacrificed. Results: Harvested tissues obtained from left ventricles in the untreated T1DM rats showed substantial damage to the cardiomyocyte ultrastructure as demonstrated by disintegrated myofibrils and their sarcomeres, damaged mitochondria and lipid droplets, which was substantially protected by insulin. Insulin also significantly inhibited T1DM-induced hyperglycemia (p < 0.001), dyslipidemia (p < 0.0001), malondialdehyde (MDA; p < 0.0001), tumor necrosis factor-alpha (TNF-α; p < 0.001) and interleukin-6 (p < 0.001). We further demonstrated a significant (p ≤ 0.001) correlation between either sarcomere or mitochondrial injury scoring and the serum levels of glucose, dyslipidemia, and biomarkers of oxidative stress (OxS) and inflammation. Conclusions: These results indicate that insulin effectively suppresses left ventricular cardiomyocyte ultrastructural damage, which substantially slows down the progression of diabetic cardiomyopathy for 8 weeks in a rat model of T1DM, possibly due to the glycemic control and inhibition of dyslipidemia, OxS and inflammation.

Swim exercise inhibits hemostatic abnormalities in a rat model of obesity and insulin resistance

BACKGROUND

We sought to determine whether swim exercise can inhibit high carbohydrate and fat diet (HCFD)-induced biomarkers of coagulation and thrombosis.

MATERIAL AND METHODS

Rats were either fed with HCFD (model group) or a standard laboratory chow (control group) for 15 weeks. Swim exercise-'treated' rats started swim exercise training from the 11^th week until being sacrificed, on Week 15.

RESULTS

HCFD caused a significant increase in blood glucose, insulin resistance (HOMA-IR), lipidemia, and inflammatory biomarkers. In addition, HCFD significantly modulated coagulation and thrombosis biomarkers; fibrinogen, plasminogen activator inhibitor-1, von Willebrand factor, prothrombin time, activated partial thromboplastin time, blood clotting and bleeding time, and ADP-induced platelet aggregation that was effectively inhibited by swimming exercises.

CONCLUSIONS

We demonstrate that in an animal model of obesity and insulin resistance, there is a significant change in hemostasis, which is ameliorated by swim exercise.

Insulin protects against hepatocyte ultrastructural damage induced by type 1 diabetes mellitus in rats

Diabetic complications that affect vital organs such as the heart and liver represent a major public health concern. The potential protective effects of the hormone insulin against hepatocyte ultrastructural alterations induced secondary to type 1 diabetes mellitus (T1DM) in a rat model of the disease have not been investigated before. Therefore, rats were injected once with 65 mg/kg streptozotocin (T1DM group) and the protection group (T1DM+Ins) received a daily injection of insulin 48 h post diabetic induction by streptozotocin and continued until being sacrificed at week 8. The harvested liver tissues were examined using transmission electron microscopy (TEM) and blood samples were assayed for biomarkers of liver injury enzyme, glycemia, lipidemia, inflammation, and oxidative stress. TEM images showed that T1DM induced profound hepatocyte ultrastructural alterations as demonstrated by pyknotic nucleus, condensation of chromatin, irregular nuclear membrane, swollen mitochondria, dilated rough endoplasmic reticulum, damaged intercellular space, and accumulation of few lipid droplets inside the hepatocyte cytoplasm, which were substantially protected with insulin. In addition, the blood chemistry profile complements the TEM data as demonstrated by an increase in serum levels of alanine aminotransferase (ALT), dyslipidemia, C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) by T1DM that were significantly (p < 0.05) reduced with insulin injections. Thus, we conclude that insulin effectively protects against T1DM-induced liver injury in rats for a period of 8 weeks, possibly due to the inhibition of inflammation, oxidative stress, and dyslipidemia.