Metformin Suppresses Thioacetamide-Induced Chronic Kidney Disease in Association with the Upregulation of AMPK and Downregulation of Oxidative Stress and Inflammation as Well as Dyslipidemia and Hypertension.

Toxic chemicals such as carbon tetrachloride and thioacetamide (TAA) are reported to induce hepato-nephrotoxicity. The potential protective outcome of the antidiabetic and pleiotropic drug metformin against TAA-induced chronic kidney disease in association with the modulation of AMP-activated protein kinase (AMPK), oxidative stress, inflammation, dyslipidemia, and systemic hypertension has not been investigated before. Therefore, 200 mg/kg TAA was injected (via the intraperitoneal route) in a model group of rats twice a week starting at week 3 for 8 weeks. The control rats were injected with the vehicle for the same period. The metformin-treated group received 200 mg/kg metformin daily for 10 weeks, beginning week 1, and received TAA injections with dosage and timing similar to those of the model group. All rats were culled at week 10. It was observed that TAA induced substantial renal injury, as demonstrated by significant kidney tissue damage and fibrosis, as well as augmented blood and kidney tissue levels of urea, creatinine, inflammation, oxidative stress, dyslipidemia, tissue inhibitor of metalloproteinases-1 (TIMP-1), and hypertension. TAA nephrotoxicity substantially inhibited the renal expression of phosphorylated AMPK. All these markers were significantly protected by metformin administration. In addition, a link between kidney fibrosis and these parameters was observed. Thus, metformin provides profound protection against TAA-induced kidney damage and fibrosis associated with the augmentation of the tissue protective enzyme AMPK and inhibition of oxidative stress, inflammation, the profibrogenic gene TIMP-1, dyslipidemia, and hypertension for a period of 10 weeks in rats.

Lipopolysaccharide induces acute lung injury and alveolar haemorrhage in association with the cytokine storm, coagulopathy and AT1R/JAK/STAT augmentation in a rat model that mimics moderate and severe Covid-19 pathology.

Progress in the study of Covid-19 disease in rodents has been hampered by the lack of angiotensin-converting enzyme 2 (ACE2; virus entry route to the target cell) affinities for the virus spike proteins across species. Therefore, we sought to determine whether a modified protocol of lipopolysaccharide (LPS)-induced acute respiratory distress syndrome in rats can mimic both cell signalling pathways as well as severe disease phenotypes of Covid-19 disease. Rats were injected via intratracheal (IT) instillation with either 15 mg/kg of LPS (model group) or saline (control group) before being killed after 3 days. A severe acute respiratory syndrome (SARS)-like effect was observed in the model group as demonstrated by the development of a "cytokine storm" (>2.7 fold increase in blood levels of IL-6, IL-17A, GM-CSF, and TNF-α), high blood ferritin, demonstrable coagulopathy, including elevated D-dimer (approximately 10-fold increase), PAI-1, PT, and APTT (p < 0.0001). In addition, LPS increased the expression of lung angiotensin II type I receptor (AT1R)-JAK-STAT axis (>4 fold increase). Chest imaging revealed bilateral small patchy opacities of the lungs. Severe lung injury was noted by the presence of both, alveolar collapse and haemorrhage, desquamation of epithelial cells in the airway lumen, infiltration of inflammatory cells (CD45+ leukocytes), widespread thickening of the interalveolar septa, and ultrastructural alterations similar to Covid-19. Thus, these findings demonstrate that IT injection of 15 mg/kg LPS into rats, induced an AT1R/JAK/STAT-mediated cytokine storm with resultant pneumonia and coagulopathy that was commensurate with moderate and severe Covid-19 disease noted in humans.

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.

Resveratrol suppresses cholestasis-induced liver injury and fibrosis in rats associated with the inhibition of TGFß1-Smad3-miR21 axis and profibrogenic and hepatic injury biomarkers.

Cholestasis caused by slowing or blockage of bile flow is a serious liver disease that can lead to liver fibrosis and cirrhosis. The link between transforming growth factor beta 1 (TGFß1), Smad family member 3 (Smad3), and microRNA 21 (miR21) in bile duct ligation (BDL)-induced liver fibrosis in the presence and absence of the anti-inflammatory and antioxidant compound, resveratrol (RSV), has not been previously studied. Therefore, we tested whether RSV can protect against BDL-induced liver fibrosis associated with the inhibition of the TGFß1-Smad3-miR21 axis and profibrogenic and hepatic injury biomarkers. The model group of rats had their bile duct ligated (BDL) for 3 weeks before being killed, whereas, the BDL-treated rats were separated into three groups that received 10, 20, and 30 mg/kg RSV daily until the end of the experiment. Using light microscopy and ultrasound examinations, we documented in the BDL group, the development of hepatic injury and fibrosis as demonstrated by hepatocytes necrosis, bile duct hyperplasia, collagen deposition, enlarged liver with increased echogenicity, irregular nodular border and dilated common bile duct, which were more effectively inhibited by the highest used RSV dosage. In addition, RSV significantly (p ≤ 0.0027) inhibited BDL-induced hepatic TGFß1, Smad3, miR21, the profibrogenic biomarker tissue inhibitor of metalloproteinases-1 (TIMP-1), malondialdehyde (MDA), interleukin-17a (IL-17a), and blood levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin. These findings show that RSV at 30 mg/kg substantially protects against BDL-induced liver injuries, which is associated with the inhibition of TGFß1-Smad3-miR21 axis, and biomarkers of profibrogenesis, oxidative stress, and inflammation.

Resveratrol ameliorates type 2 diabetes mellitus-induced alterations to the knee joint articular cartilage ultrastructure in rats.

Diabetes-induced osteoarthritis (OA) is a chronic inflammatory disease that damages the cartilage in the joints and could lead to disability. The protective effect of the antioxidant and anti-inflammatory agent, resveratrol, against alterations to the knee articular cartilage ultrastructure induced by type 2 diabetes mellitus (T2DM) associated with the inhibition of dyslipidemia, oxidative stress, and inflammation has not been investigated before. Therefore, we modeled OA in rats 10 weeks post diabetic induction using a high carbohydrate and fat diet and a single injection of streptozotocin (50 mg/kg body weight), and the protective group of rats started resveratrol (30 mg/kg; orally) treatment 2 weeks before diabetic induction and continued on resveratrol until the end of the experiment at week 12. Blood chemistry analysis confirmed hyperglycemia (elevated glucose and glycated hemoglobin, HbA1c), dyslipidemia (elevated triglyceride, cholesterol, and low-density lipoprotein-cholesterol), and upregulation of oxidative stress (malondialdehyde) and inflammatory (C-reactive protein and tumor necrosis factor-α) biomarkers in the model group. In addition, using light and electron microscopy examinations, we also observed in the model group substantial damage to the articular cartilage and profound chondrocyte and territorial matrix ultrastructural alterations such as chondrocytes with degenerated nucleus and mitochondria, scarce cytoplasmic processes, and absence of the fine fibrillar appearance of territorial matrix. Resveratrol pretreatment significantly (p ≤ 0.0029) but not completely protected from T2DM-induced OA. We conclude that resveratrol protects against alterations to the articular cartilage ultrastructure induced secondary to T2DM in rats, which is associated with the inhibition of glycemia, hyperlipidemia, and biomarkers of oxidative stress and inflammation.

Inhibition of GSK3ß protects against collagen type II-induced arthritis associated with a decrease in synovial leukocyte infiltration and inhibition of endoplasmic reticulum stress and autophagy biomarkers.

We sought to determine whether TDZD-8, the inhibitor of the glycogen synthase kinase-3ß (GSK3ß), can protect the synovial membrane of the knee joint against injuries induced by collagen type II immunization (CIA) possibly via the downregulation of synovial leukocyte infiltration, endoplasmic reticulum stress (ERS), and autophagy. The model group of rats (CIA) were immunized over a period of 3 weeks with collagen type II, whereas the treated group of rats (CIA + TDZD-8) were treated with TDZD-8 (1 mg/kg) for 21 days after the completion of the immunization regimen. All rats were then killed at week 6. Harvested synovial tissues were prepared for immunohistochemistry staining, and synovial homogenates were assayed for biomarkers of ERS, autophagy, apoptosis, and cell survival and proliferation. In addition, blood samples were assayed for biomarkers of arthritis. Synovial tissue images showed that CIA enhanced leukocyte recruitment as demonstrated by an increased CD45+ (leukocyte common antigen) immunostaining, which was markedly decreased by TDZD-8. TDZD-8 also significantly (P < .05) inhibited collagen-induced autophagy biomarkers Beclin-1 and LC3II, the ERS biomarkers GRP-78, IRE1-α, XBPIs, and eIF2a, and the survival protein Bcl-2. Whereas, the collagen-induced proliferative biomarkers Akt and mTOR were not inhibited by TDZD-8, and CIA inhibited the apoptotic proteins CHOP and cleaved caspase-3, which were augmented by TDZD-8. We further demonstrated a significant (P < .05) correlation between autoantibodies generated during the course of arthritis and biomarkers of ERS and autophagy. We conclude that TDZD-8 inhibits CIA and decreases synovial leukocyte infiltration, ERS, and autophagy, which is independent of Akt/mTOR signalling.

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 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 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 inhibits mTOR-HIF-1α axis and profibrogenic and inflammatory biomarkers in thioacetamide-induced hepatic tissue alterations.

The potential inhibitory effect of the antidiabetic and anti-inflammatory drug, metformin on thioacetamide (TAA)-induced hepatotoxicity associated with the inhibition of mammalian target of rapamycin (mTOR)-hypoxia-inducible factor-1α (HIF-1α) axis has not been investigated before. Therefore, we tested whether metformin can protect against liver injuries including fibrosis induced by TAA possibly via the downregulation of mTOR-HIF-1α axis and profibrogenic and inflammatory biomarkers. Rats either injected with TAA (200 mg/kg; twice a week for 8 weeks) before being killed after 10 weeks (model group) or were pretreated with metformin (200 mg/kg) daily for 2 weeks before TAA injections and continued receiving both agents until the end of the experiment, at Week 10 (protective group). Using light and electron microscopy examinations, we observed in the model group substantial damage to the hepatocytes and liver tissue such as collagen deposition, infiltration of inflammatory cells, and degenerative cellular changes with ballooned mitochondria that were substantially ameliorated by metformin. Metformin also significantly ( p < 0.05) inhibited TAA-induced HIF-1α, mTOR, the profibrogenic biomarker α-smooth muscle actin, tissue inhibitor of metalloproteinases-1, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), alanine aminotransferase (ALT) and aspartate aminotransferase in harvested liver homogenates and blood samples. In addition, a significant ( p < 0.01) positive correlation between hypoxia scoring (HIF-1α) and the serum levels of TNF-α ( r = 0.797), IL-6 ( r = 0.859), and ALT ( r = 0.760) was observed. We conclude that metformin protects against TAA-induced hepatic injuries in rats, which is associated with the inhibition of mTOR-HIF-1α axis and profibrogenic and inflammatory biomarkers; thus, may offer therapeutic potential in humans.

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.

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.

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.

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.

Vitamin E protects against monosodium glutamate-induced acute liver injury and hepatocyte ultrastructural alterations in rats.

Food additives such as nitrates and nitrites, and monosodium glutamate (MSG) used in the food industry increase the risk of certain cancers and inflict damage to vital organs. We sought to determine whether the antioxidant vitamin E can protect against liver injuries induced by a toxic dose of MSG in a rat model of MSG-induced acute liver injury. The model group of rats received a daily dose of MSG (4 gm/kg) for 7 days, whereas the protective groups were either received a 100 mg/kg vitamin E plus MSG or 300 mg/kg vitamin E plus MSG for 7 days. Rats were then sacrificed at day 8. Transmission and light microscopy images revealed substantial liver tissue damage induced by MSG in the model group as demonstrated by apoptotic hepatocytes with Pyknotic nuclei and irregular nuclear membrane, and cytoplasm displayed many vacuoles, swollen mitochondria, dilated endoplasmic reticulum, dilated blood sinusoids and bundles of collagen fibers in extracellular space. Treatment of the model group with vitamin E showed a substantial protection of liver tissue and hepatocellular architecture by 300 mg/kg vitamin E compared to a partial protection by 100 mg/kg vitamin E. In addition, MSG significantly (p < .05) modulated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione peroxidase (GPx), which were significantly (p < .05) protected with vitamin E. Thus, vitamin E at 300 mg/kg effectively protects against MSG-induced acute liver injury in rats, possibly via the inhibition of inflammation, and up-regulation of endogenous antioxidants.

Swim exercise training ameliorates hepatocyte ultrastructural alterations in rats fed on a high fat and sugar diet.

Excessive consumption of carbohydrate and fat increases the risk of liver disease. We hypothesized that swim exercise can protect hepatocytes from ultra-structural damage induced by high cholesterol and fructose diets (HCFD). Rats were either fed with HCFD (model group) or a standard laboratory chow (control group) for 15 weeks before being sacrificed. Swim exercise trained rats started the treatment from the 11th week until the sacrifice day, end of week 15. Blood samples were assayed for biomarkers of liver injury and adiponectin. The harvested liver tissues were examined using transmission electron microscopy (TEM). TEM images revealed substantial damage and accumulation of lipid droplets (steatosis) in the hepatocytes of the model group that was inhibited by swim exercise. In addition, HCFD significantly (p < 0.0005) increased insulin resistance index (HOMA-IR), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), which were effectively (p < 0.02) decreased by a swim exercise to levels comparable to control group. Whereas, swim exercise increased adiponectin levels in HCFD group (p < 0.03). These results show that HCFD-induced hepatic injury is ameliorated by swim training exercise possibly via restoration of a normal blood sugar and lipid, induction of adiponectin and inhibition of inflammatory, and liver injury biomarkers.

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.

Exercise protects against insulin-dependent diabetes-induced osteoarthritis in rats: A scanning electron microscopy study.

We tested the hypothesis that swim exercise can protect the articular cartilage from damages induced secondary to insulin-dependent diabetes mellitus in rats using the scanning electron microscopy and to monitor the blood levels of oxidative and antioxidative stress biomarkers that are known to be modulated in osteoarthritis (OA). A profound damage to the cartilage was observed in the diabetic rats. Our findings also show that swim exercise protects the knee joints from damage induced by diabetes as well as significantly inhibiting OA-induced upregulation of thiobarbituric acid reactive substances (TBARS) and tumor necrosis factor alpha (TNF-α) and augmented superoxide dismutase (SOD) inhibition by OA. Thus, we demonstrated an effective protection by swim exercise against diabetes-induced OA in a rat model of the disease.

Loss of Akt activity increases circulating soluble endoglin release in preeclampsia: identification of inter-dependency between Akt-1 and heme oxygenase-1.

AIMS: Endothelial dysfunction is a hallmark of preeclampsia. Desensitization of the phosphoinositide 3-kinase (PI3K)/Akt pathway underlies endothelial dysfunction and haeme oxygenase-1 (HO-1) is decreased in preeclampsia. To identify therapeutic targets, we sought to assess whether these two regulators act to suppress soluble endoglin (sEng), an antagonist of transforming growth factor-ß (TGF-ß) signalling, which is known to be elevated in preeclampsia. METHODS AND RESULTS: Vascular endothelial growth factor-A (VEGF-A), fibroblast growth factor (FGF-2), angiopoietin-1 (Ang-1), and insulin, which all activate the PI3K/Akt pathway, inhibited the release of sEng from endothelial cells. Inhibition of the PI3K/Akt pathway, by overexpression of phosphatase and tensin homolog (PTEN) or a dominant-negative isoform of Akt (Akt(dn)) induced sEng release from endothelial cells and prevented the inhibitory effect of VEGF-A. Conversely, overexpression of a constitutively active Akt (Akt(myr)) inhibited PTEN and cytokine-induced sEng release. Systemic delivery of Akt(myr) to mice significantly reduced circulating sEng, whereas Akt(dn) promoted sEng release. Phosphorylation of Akt was reduced in preeclamptic placenta and this correlated with the elevated level of circulating sEng. Knock-down of Akt using siRNA prevented HO-1-mediated inhibition of sEng release and reduced HO-1 expression. Furthermore, HO-1 null mice have reduced phosphorylated Akt in their organs and overexpression of Akt(myr) failed to suppress the elevated levels of sEng detected in HO-1 null mice, indicating that HO-1 is required for the Akt-mediated inhibition of sEng. CONCLUSION: The loss of PI3K/Akt and/or HO-1 activity promotes sEng release and positive manipulation of these pathways offers a strategy to circumvent endothelial dysfunction.

Vitamin E protects against the modulation of TNF-α-AMPK axis and inhibits pancreas injury in a rat model of L-arginine-induced acute necrotising pancreatitis.

BACKGROUND: Acute pancreatitis (AP) associated with the modulation of TNF-α-AMPK axis in the presence and absence of vitamin E has not been investigated before. MATERIAL AND METHODS: Rats were either injected with L-arginine (2.5 gm/kg) before being sacrificed after 48 h or were pre-treated with vitamin E (60 mg/kg) and continued receiving vitamin E until the end of the experiment. RESULTS: AP was developed as demonstrated by infiltration of inflammatory cells and profound pancreas tissue damage, which were substantially protected by vitamin E. In addition, L-arginine injections significantly (p < .0001) increased the expression of TNF-α mRNA and protein, and decreased phospho-AMPK and IL-10 mRNA and protein that was significantly (p < .0001) protected by vitamin E. Furthermore, vitamin E inhibited L-arginine-induced blood levels of LDH, amylase, and myeloperoxidase. CONCLUSIONS: L-arginine-induced acute pancreatitis modulates TNF-α-AMPK axis, IL-10 and other AP biomarkers, which is protected by vitamin E; thus, may offer therapeutic potential in humans.